1 ! i I ! Class iSSHJ- Copyright N^_ Mil CC£VR1CHT DEPOSrr. INSECT PESTS OF FARM, GARDEN AND ORCHARD BY E. DWIGHT SANDERSON 11 Formerly Entomologist of the Delaware, Texas and Neiv Hampshire Agricultural Experiment Stations and Director of the New Hampshire and West Virginia Agricultural Experiment Stations. SECOND EDITION REVISED AND ENLARGED BY LEONARD MARION PEAIRS Professor of Entomology West Virginia University NEW YORK JOHN WILEY AND SONS, Inc. LovDov : CHAPMAN & HALL, Limited. 1921 COPYRIGHT, 1912 BY E. DWIGHT SANDERSON COPYRIGHT, 1921 BY E. DWIGHT SANDERSON AND LEONARD M. PEAIRS Printed in the U. S. A. APR 27 1921 ?)CI.A611805 PREFACE The edition of the writer's "Insects Injurious to Staple Crops," first published ten years ago, having been exhausted, the publishers requested a revision. It was found, however, that the advances in economic entomology during the past decade were such that it was necessary practically to rewrite the book. At the time it was first published two other books were projected; one to deal with the insects affecting garden crops, and the other to discuss those affecting fruits. Pressure of regular work pre- vented the author from completing the manuscript for these works and in 1907 Dr. Chittenden issued his excellent book on " Insects Injurious to Vegetables," so that there seemed to be no immediate demand for another volume on that subject. At the same time two other well-known entomologists were work- ing upon books which would cover fruit insects, so that the writer abandoned the field to them. Subsequently, the work of one of these friends was cut short by his sudden death, and the other abandoned the task, at least for the present. Under these circumstances, it seemed that there was a distinct place for a book to cover all the insects affecting the crops of farm, garden and orchard, and having leisure to devote to it, the author developed the work in its present form. It has been the author's effort to discuss all of the more impor- tant insects of farm, and garden and orchard at sufficient length to give a clear idea of their life histories and habits, and also the best means of control, so that the book may be used as a reference work both by the student of economic entomology and by the practical farmer, gardener, or fruit-grower. Insects of minor or local importance have been purposely omitted. The insects of practically all of the leading crops are considered, except the citrus fruits. With these the author is unfamiliar, but it is hoped to add a chapter upon them by a competent authority in a subsequent edition. In general, the discussion of insects ii PREFACE and their control as given is based upon conditions east of the Rockies, and practically no consideration has been given to the conditions of the Pacific Coast or of the irrigated country of the far West. The author is well aware that there are doubtless many errors of fact or of wrong emphasis in these pages. Such must nec- essarily be the case in a work the greater part of which must be compiled. All of the leading authorities on the subject discussed have been consulted and the writer has endeavored to present their evidence fairly, with such interpretation as his personal knowledge made possible. He will be greatly indebted to those who will aid him in securing the accuracy of the work by report- ing any errors or by suggesting improvements in it, as it is hoped to revise the pages from time to time so that they may serve as a reliable reference work upon our insect pests of ihe farm, the garden, and the orchard. On the following pages are given the sources from which the illustrations have been secured, but the author wishes to express his special appreciation of the very large number of figures which were furnished him by Dr. L. 0. Howard, Chief of the Bureau of Entomology, and Mr. J. A. Arnold, Chief of the Division of Publications, of the United States Department of Agriculture, either as electrotypes or original drawings or photo- graphs, and to Ginn & Company of Boston, for the loan of numerous electrotypes made for an Elementary Entomology by Prof. C. F. Jackson and the writer, now being pubUshed by them. E. DwiGKT Sanderson. West Virginia University, morqantown. PREFACE TO THE SECOND EDITION. No better indication of the activity of the students of American economic entomology could be cited than the fact that a text book dealing with injurious insects requires revision at rather frequent intervals. The present revision is issued in the hope that it may record in some measure the progress which investi- gators have made since the book was first prepared. Since the pubHcation of the first edition the senior author has left active work in economic entomology, but he has been fortunate in securing the collaboration of his former colleague, who has made a thorough revision of the original text. He has added several new articles and three new chapters deahng with the insect pests directly affecting man and the domestic animals and with the insects affecting citrus fruits. Other changes in the text will be found to be minor ones, with the exception of the additions mentioned, and are mainly for the purpose of bringing up to date the recommendations for control. No attempt to conform to the latest usage in naming of famihes has been made for the reason that most students using this text will be more familiar with the names as used in Com- stock's Manual than with the modern usage. May, 1920. E. Dwight Sanderson. Ill ACKNOWLEDGEMENTS The authors wish to express their sincere appreciation of the courtesy extended -by those friends mentioned below who have assisted in this work by furnishing electrotypes, photographs and drawings, thus making possible the illustration of the volume. The United States Department of Agriculture, through Dr. L. O. Howard, Chief of the Bureau of Entomology, and Mr. J. A. A. Arnold, Chief of the Division of Publications, furnished a large number of electrotypes and plates. The illustrations cred- ited to Dr. C. V. Riley have been secured from various sources. Dr. S. A. Forbes, State Entomologist of Ilhnois, Prof. Glen W. Herrick of Cornell University, Prof. F. L. Washburn of Min- nesota, Prof. H. A. Gossard of the Ohio Station, Prof. R. H. Petit of Michigan Agr. College, Prof. P. J. Parrott of the New York Station at Geneva, and the late Dr. John B. Smith of New Jersey, all furnished several illustrations. Prof. W. E. Rumsey of West Virginia made his excellent collection of photo- graphs available. Prof. H. Garman of Kentucky, Director R. W. Thatcher of the Washington Expt. Station, Prof. S. J. Hunter of the University of Kansas, Prof . T. B. Symons of Maryland, Prof. H. E.Summers of Iowa, Director P. H. Rolfs of the Florida Station, Dr. T. C. Johnson of the Virginia Truck Station, Director J. C. Kendall of the New Hampshire Station, Director S. W. Fletcher of the Vir- ginia Station, Dr. W. E. Britton of Connecticut, Prof. R. I. Smith of North Carolina, Dr. A. L. Quaintance of the Bureau of Ento- mology, Director F. B. Mumford of the Missouri Station, and Prof. C. S. Crandall of the Ilhnois Station, all furnished several valuable illustrations. Dr. E. W. Berger kindly read over the copy for the chapter on Citrus Fruit Insects and assisted by correcting mistaken statements and offering many helpful suggestions for the im- provement of the chapter. iV ACKNOWLEDGEMENTS v The Friend Mfg. Co., The Deming Co., F. E. Myers and Bro., The Spraymotor Co., E. C. Brown and Co., The Goulds Mfg. Co., and the Bean Spray Pump Co., all makers of spraying appUances, furnished many of the illustrations of such apparatus, while the Corona Chemical Co. and the Niagara Sprayer Co. furnished some of the illustrations of dusters. The Orange Judd Publishing Co. furnished some of the Riley figures. Many others helped by allowing their illustrations to be used. All illustrations have been properly credited in the text. Credit for much of the direct and indirect assistance freely given by many persons can not be extended to individuals but is none the less appreciated. The publishers of this volume, John Wiley and Sons, Inc., have done all in their power to cooperate with the authors and make the task of preparing the manuscript as light as possible, and to them and their organization we wish to extend our thanks. CONTENTS Preface to the First Edition i Preface to the Revised Edition iii Acknowledgments iv Chapter page I. Injury to Crops by Insect Pests 1 II. Beneficial Insects, Predaceous and Parasitic 8 III. Structure and Development of Insects^ 20 IV^ri'ARM Methods for the Control of iNSECTsy. 29 V.tInsecticides ^. A, 39 Vli^^RAYiNG and Dusting Apparatus .! ( 59 VII. Insects Affecting Grains, Grasses and "Miscellaneous Crops 78 VIII. Insects Injurious to Small Grains 117 IX. Insects Injurious to Corn 143 X. Insects Injurious to Stored Grains 176 XI. Insects Injurious to Clover and Alfalfa 189 XII. Insects Injurious to Tobacco 212 XIII. Insects Injurious to Cotton 226 XIV. Insects Injurious to Potatoes and Tomatoes 256 XV. Insects Injurious to Beans and Peas 278 XVI. Insects Injurious to Beets and Spinach 299 XVII. Insects Injurious to Cabbage and Related Crops 314 XVIII. Insects Injurious to Melons, Cucumbers, Squash, Etc . . 340 XIX. Insects Injurious to Miscellaneous Garden Crops 361 XX. Insects Injurious to the Strawberry 389 XXI. Insects Injurious to the Raspberry and Blackberry .... 403 XXII. Insects Injurious to the Currant and Gooseberry 418 XXIII. Insects Injurious to the Grape 432 XXIV. Insects Injurious to Orchard Fruits 470 XXV. Insects Injurious to the Apple and Pear 514 XXVI. Insects Injurious to the Peach, Plum and Cherry 575 XXVII. Insects Injurious to Citrus Fruits 599 XXVIII. Insects Injurious to Man and in the Household 635 XXIX. Insects Injurious to Domestic Animals and Poultry. . . . 657 Bibliography 689 Index 692 vi INSECT PESTS OF FARM, GARDEN AND ORCHARD CHAPTER I THE INJURY TO CROPS BY INSECT PESTS Ever since the locust plagues in the time of the Pharaohs his- tory is replete with accounts of insect scourges and the enormous losses they have caused the agriculturists of all ages. However, instead of diminishing with the advancement of agricultural methods, injurious insects have undoubtedly become both more numerous and more destructive in modern times. " In no coun- try in the world do insects impose a heavier tax on farm products than in the United States. The losses resulting from the depre- dations of insects on all the plant products of the soil, both in their growing and in their stored state, together with those on live stock, exceed the entire expenditures of the National Gov- ernment, including the pension roll and the maintenance of the Army and the Navy."* '' Very careful estimates, based on crop reports and actual insect damage over a series of years, show that the loss due to insect pests of farm products, including fruits and hve stock, now reaches the almost inconceivable total of $1,000,000,000, annually."! The above quotations from Mr. C. L. Marlatt; Assistant Chief of the Bureau of Entomology, United States Department of Agriculture, may appear to the reader either ludicrous or startling, according to the extent of his infor- mation concerning the role which insects play in our Agricultural * C. L. Marlatt, Yearbook IT. S. Department of Agriculture, 1904, p. 461. I C. L. Marlatt, Journal of Economic Entomology, IV, 109. 2 INSECT PESTS OF FARM, GARDEN AND ORCHARD economy, which forms the warp of American prosperity. It should be borne in mind that these figures are based on pre-war estimates and that they now need considerable revision upward but that the totals will not reach the amounts expended by the nation during a state of war, A brief resume of the damage done by insect pests, of the costs of fighting them and of the estimates which form the basis for the above statements will make them more convincing. Growing Cereals. — Probably no insect does as widespread damage as the Hessian-fiy, attacking our chief staple, wheat, as well as rye and barley. One-tenth of the whole crop, valued at $150,000,000 to $175,000,000 is generally conceded to be destroyed by this pest every year. In some sections the loss is frequently as great as 30 to 50 per cent, and it undoubtedly was responsible in a great measure for the necessity for governmental regulations of the use of wheat flour during the great war. The southern grain-louse or " green-bug " caused a loss estimated at from $5,000,000 to $10,000,000 in Texas, Oklahoma and Kansas in 1907, and every year there is a considerable shrinkage in the wheat crop as a result of the presence of this and other species of plant- lice. This injury will doubtless amount, on the average, to as much as 2 or 3 per cent of the entire crop, worth from $30,000,000 to $50,000,000. The corn crop of 1919 was worth at least three and one-half billions of dollars. The total was reduced at least two to three per cent by the chinch-bug and not less than 5 per cent by the corn-earworm while other insects accounted for several per cent more or less. Estimating the total insect depreciation of this crop at only ten per cent gives a total of $350,000,000 for the one year. The total value of cereal crops in 1919 was over$7,000,000,000, which was undoubtedly at least ten per cent less than it would have been could the insect injury have been totally eliminated. Hay and Forage Crops. — A host of small insects attack our grasses and forage crops, many of them being so small that they are unnoticed, though their aggregate injury is sometimes enormous. Of the larger pests of grasses and forage plants the army worms are among the best known and have often caused a loss of over half a million dollars to a single state in one season. INJURY TO CROPS BY INSECT PESTS 3 Grasshoppers of various species are also always more or less injurious and often become a serious menace. Probably the most serious injury, however, is done by subterranean larva) such as the cut-worms, wireworms, white grubs, and webworms, which breed in sod land, and by the hordes of little leaf -hoppers which are always prevalent, but whose injury often passes unnoticed. Ten per cent of the haj' crop was worth $150,000,000 in 1919 and this is a fair estimate of the damage done to hay and forage crops by their insect enemies. Cotton. — The cotton plant has a number of injurious insect enemies, of which the boll weevil, bollworm, and leafworm are the most injurious. In 1904 the writer made a statistical study of the decrease in the cotton crop of Texas due to the boll weevil, and showed that it was then costing that state $25,000,000 per annum.* This estimate has been confirmed by independent investigations made by Mr. W. D. Hunter of the U. S. Bureau of Entomology, and although the loss in Texas is not so serious at present, the weevil has spread eastward as far as Georgia, so that its total injury remains practically the same, and has undoubtedly been a large factor in the higher price of cotton in recent years. The bollworm is most injurious in the south- western cotton-producing States, where it causes a loss from 5 to 60 per cent of the crop. The total damage to cotton by the bollworm is approximately $100,000,000 per annum and not infrequently exceeds that amount. In 1880 the United States Entomological Commission made an investigation of the cotton worm and valued its ravages at $30,000,000, but with the extensive use of Paris green and arsenical poisons its injury has been greatly reduced and now amounts to from $5,000,000 to $20,000,000 annually. Various minor pests of the cotton plant inflict a considerable amount of local injury and with the above pests damage the crop at least 10 per cent, worth $160,000,000 in 1919. Tobacco. — Tobacco is attacked by insects, which form one of the chief " bugbears " of tobacco growing, at all stages of its existence. Ten per cent of the crop, worth $35,000,000, is cer- tainly destroyed by them every year. * E. D. Sanderson, The Boll Weevil and the Cotton Crop of Texas. (Bul- letin Dept. of Agriculture, Insurance, Statistics and History, Austin, Texas, 1905, p. 28, 7 maps.) 4 INSECT PESTS OF FARM, GARDEN AND ORCHARD Truck Crops. — Truck crops are peculiarly susceptible to insect attacks, and their control forms one of the chief items in the cost of production. It is safe to say that truck crops suffer from insect ravages fully twice as much as do the staples, or 20 per cent of their total value. Statistics are not available for the present value of truck crops, but they were probably worth $1,500,000,000 in 1919, making the insect tax for the trucker fully $300,000,000. Fruits. — Fruit trees are also much more seriously injured by insects than are the staple crops, and their control involves a large expense to the fruit-grower. Where it is not combated, the codhng moth, or apple worm, causes a loss of from 30 to 50 per cent of the crop, and where it is controlled by spraying a considerable expense is involved. The loss and cost of treatment for this pest alone amount, to $35,000,000 for the United States, and were it not for the fact that it is now largely controlled in the principal fruit-growing sections, the loss would be double or treble this sum. The loss due to the San Jose scale is difficult to estimate, but it is well known that it has destroyed milhons of trees and that in the principal fruit regions where this pest is prevalent it is necessary to treat the trees annually at a cost of from 10 to 25 cents per tree, so that $10,000,000 a year would be a very conservative estimate of its annual cost. Both deciduous and citrus fruits have a host of insect pests, always present and doing more or less damage and occasionally becoming so abundant as to threaten the life of the trees or their crops. Fifteen per cent of the value of our fruit products, worth at least $75,000,000, is certainly destroyed by insect pests every year. Forest Insects. — Only those who have had opportunity to observe the ravages of insects in timber and in timber products can appreciate the enormous losses which they occasion. Prob- ably no one is better informed upon this matter than Dr. A. D. Hopkins, in charge of the Forest Insect Investigations of the U. S. Bureau of Entomology, who has made a life study of these pests in all parts of the country. In a recent circular* he states that " the amount of insect-killed and damaged timber left in the woods, plus the reduction in value of that utilized, to be charged *A. D. Hopkins, Circular 129, Bureau of Entomology, U. S. Dept. Agr. INJURY TO CROPS BY INSECT PESTS 5 to insects is not far from an equivalent of 10 per cent of the value of the annual output of forest products of all kinds, in the rough. The total value of the forest products of the United States in 1907 is given as $1,280,000,000; the losses from insect depredations would therefore represent an annual loss in cash value of more than $100,000,000." To this should be added a similar loss to farm woodlots, which may be estimated at an additional $10,000,000. The insect injury to the shade trees of city streets, parks, and estates should also be mentioned, for such pests as the gypsy moth, the elm leaf-beetle, tussock moths, etc., are not only causing enormous losses and large expense for their control, but they are often reducing the values of real estate and through killing the trees are destroying the scenic value of property and changing the esthetic environment in a manner which it will require many decades to remedy, if the previous conditions can ever be even partially reproduced. The State Forester of Massachusetts has recently shown that the New England States and the Federal Government have spent fully $7,000,000 in fighting the gypsy and brown-tail moths in New England, and at the present time the New England States, the Federal Government, municipalities and private individuals are spending over $1,000,000 per annum in this warfare for the preservation of their shade and forest trees. Live Stock. — Insect pests, including the ticks and mites, are almost as important as enemies of live stock as of crops. The principal drawback to cattle raising in the South is the Texas fever, transmitted by the cattle tick, which has been charged by the officials of the bureau of Animal Industry with a loss of $100,000,000 annually. The ox-warble, which causes the "grubby" hides of cattle, causes a loss estimated at from $30,000,000 to $50,000,000 per year due to the depreciated value of the hides and the lessened quantity and poorer quality of the beef of affected animals. The screw-worm fly is a constant annoyance to cattle and source of loss on the range, and numerous biting and parasitic flies cause a considerable loss to the grower of live stock, both through actual damage and through the annoyance preventing growth and production. The sheep scab, sheep tick, the sheep bot — causing " staggers " or " grub-in-the-head "— horn-fly, buffalo-fly, black- fly, and numerous species of lice which affect all of the domestic animals, are among the pests which must be combated by the 6 INSECT PESTS OF FARM, GARDEN AND ORCHARD stockman. In 1919 the live stock products were worth $8,000,000,000, and it is estimated that fully 10 per cent of this amount was lost through injury from insects. Stored Products. — Even after the crops have been gathered and garnered, and indeed after they and animal products have been manufactured, they are constantly subject to the attacks of numerous " weevils," " moths," and other insect pests of stored products. Every housewife and every merchant knows that only through constant surveillance these ravages can be prevented. Mills, tobacco warehouses, storage houses, and vessels, must be frequently cleaned and often must be fumigated to prevent the increase of insect pests peculiar to them. It is estimated that at least 3 per cent of the cereal crops are destroyed by insects while in storage, which would mean a loss of $200,000,000, and in many cases the loss to corn, particularly in the South, is much greater. The total loss due to insects in stored goods of all kinds is impos- sible to estimate, but would fall not far short of $300,000,000. With this brief statement of the losses due to insect pests we may summarize them in a table which will show that the total is based upon conservative estimates. Annual Values of Farm Crops and Losses Chargeable to Insect Pests*. PRODUCT Cereals Hay and Forage . . . . Cotton Tobacco Truck Crops Sugars Fruits Farm Forests Miscellaneous Crops Animal Products . . . . VALUE $7,000,000,000 1,500,000,000 1,600,000,000 375,000,000 1,500,000,000 200,000,000 500,000,000 110,000,000 250,000,000 8,000,000,000 PERCENTAGE OF LOSS Total $21,035,000,000 Natural Forests and Forest Products. Products in Storage Grand Total . 10 10 10 10 20 10 15 10 5 5 AMOUNT OF LOSS $700,000,000 150,000,000 160,000,000 37,500,000 300,000,000 20,000,000 75,000,000 11,000,000 12,500,000 400,000,000 $1,866,000,000 100,000,000 300,000,000 $2,266,000,000 ♦Based on estimates from the U. S. Bureau of Entomology with modifications by the writers. Crop values based on estimates from the U. S. Department of Agriculture Year- book for 1918 and various estimates for the year 1919. INJURY TO CROPS BY INSECT PESTS 7 This table will indicate that two billions of dollars is a con- servative estimate of the damage done by insects annually to the agricultural interests of the country. The old saying, " One man's loss is another man's gain " will not apply to this damage. While the fluctuation in the amount of crops does influence prices received by the farmers it does not obviate the loss, even though the farmer receives as much money for the reduced crop as he would have for a full crop. The effect is merely to shift the burden of the loss from the farmer to the consumer. The damage done by the insects remains as a definite destruction of wealth of the community just as truly as loss from fire and storm, even though such loss is borne not by the owner of the property destroyed but by an insurance company. A real benefit to the community at large from these insects is coming to be recognized more and more. That is, that to succeed against the handicaps of insect injury as well as the other hazards incident to modern agriculture, the farmer must be- come a student of the factors insuring success. He must, as he usually can, learn the methods of agriculture best suited to pre- vent the loss from insects. This will tend to broaden his educa- tion, to make him more observant of conditions affecting suc- cessful farming and indirectly is bound to make him a more intelligent and efficient farmer and a better citizen. Who can say that such benefit does not largely overbalance the tremendous loss due to the presence of the insects . CHAPTER II BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC Ladybird-beetles After his strawberries have been ruined by the strawberry weevil, the garden truck by cutworms, the wheat despoiled by the Hessian fly, the melon-patch fallen a prey to plant-lice, and the fruit crop has been a failure on account of the codhng moth, plum curculio, and San Jose scale, it is scarcely surprising that the farmer does as one of my acquaintances did and " orders the hands to kill everything that crawls." But such would be entirely too heroic a measure, and if strictly adhered to the remedy would be as bad as the disease, for it would mean not only useless labor, but the destruction of the most effect- ive means whereby insect pests are held in check. We pride ourselves — and justly — that with our spray pumps and deadly sprays many crops can be effectually protected; but were it not for those other insects which feed upon these injurious forms, what an enormous, and, in some instances, futile task it would be ! Among these beneficial insects the Httle ladybird-beetles of the family Coccinellidce are entitled to be in the first rank. Almost all these beetles and larvae feed upon plant-hce and scale insects. Of such value are those feeding upon scale insects that not many years ago several Austrahan species were imported into CaUfornia that they might prey upon the San Jose and other scales. One of these was eminently successful and almost com- pletely destroyed the cottony cushion-scale. Of those feeding upon plant-hce, one of the most common is the Nine-spotted Ladybird (Coccinellanovemnotata). This beetle is about one-fourth of an inch long, with black head and body. The wing-covers are orange-yellow marked with nine black spots — four on each side and one on the central suture. The larva has been fancied to resemble a miniature alhgator; it is nearly twice as long as wide, almost black, marked with bluish and orange spots, and has long legs, which carry it around quite rapidly. The beetles hibernate during the winter and BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC 9 come forth in the spring and lay their eggs wherever the young will be able to find food when they hatch. When the larva has satisfied its ravenpus appetite and become full grown it fastens itself to a leaf or twig, — seemingly by its tail, if such Fig. 1. — The nine-spotted ladybird (Coccinella novemnotata) , and its larva; enlarged. (After Chittenden, U. S. Dept. Agr.) a term might be allowed, — transforms to the pupa, and in a week or ten days the adult beetle emerges from the pupal skin. This life-cycle is repeated several times during the summer season, before the fall brood enters winter quarters. Another very common form among plant-lice on garden truck is the little Adalia bipundata, or Two-spotted Ladybird. It is Fig. 2. — The two-spotted ladybird {Adalia bipundata): a, larva; 6, mouth- parts of same; c, claw of same; d, pupa; e, adult; /, antenna of same; all enlarged. (After Marlatt, U. S. Dept. Agr.) slightly smaller than the preceding, and with only one black spot on each wing-cover (Fig. 2). 10 INSECT PESTS OF FARM, GARDEN AND ORCHARD Several other species, in the genus Hippodamia, are very- useful, and among them the Convergent Ladybird {Hippo- damia convergens) is one of the best known. Its name is received from two white dashes on the black thorax, which converge posteriorly. The thorax has also a white margin, and there are thirteen black dots on its orange wing-covers. These larvae Fig. 3. — The convergent ladybird {Hippodamia convergens): a, adult; b, pupa; c, larva; enlarged. (After Chittenden, U. S. Dept. Agr.) and beetles are very common among the plant-lice on melon- vines, and are an important factor in their extermination. They have also been noted for eating the black peach aphis and many other plant-lice. A form which is often very abundant among plant-lice on corn is the Spotted Ladybird (Megilla maculata). The head, thorax, Fig. 4. — The spotted ladybird (Meqilla maculata): a, larva; b, pupa; c, adult; enlarged. (After Chittenden, U. S. Dept. Agr.) and wing-covers are a dark pink, with two black spots on the thorax and ten on the wing-covers. Such numbers of these BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC 11 Fig. 5. — The twice-stabbed lady- bird (Chilocorus hivulnerus). a, adult; h, larva; enlarged. (After Riley.) little fellows have frequently been found huddled together under the rubbish at the base of some tree in a last year's cornfield that they might be taken up by the handful without difficulty. Many other species feed upon plant-lice, but the above are the most common, and all bear a resemblance to one another, being generally orange or red with black spots, and of a characteristic round or oval form, flattened below, so that the legs may be drawn in under the wing-covers. Those ladybirds which feed upon scales are much smaller and are black, though sometimes spotted with red or orange. As far as known, there is no way in which these useful allies may be encouraged or increased in numbers, but it is trusted that the above may give such a brief view of their habits that fewer may be killed through ignorance concerning their true worth. Syrphus-flies Besides the little beetles described above there is a family of flies, the Syrphidce, many of whose larvae feed upon plant- lice. This family is a very large one, and thus the habits of its different members vary considerably. One of them, the drone- fly, so closely resembles a honey- bee as to be almost indistin- guishable from it. The larva of this fly {Eristalis tenax) is one of the common rat-tailed mag- gots which are found in putrid matter. It is thought that the old " bugonia " superstition of the ancients that bees came from maggots in dead animals, etc., was due to the confusion of this fly with honey-bee. In another group of the family, the adult flies of which also quite closely resembles bees, the larvse are parasitic in the nests of honey- and bumble-bees, feeding upon their larvae. Fig. 6. — Syrphus ribesii; enlarged. 12 NSECT PESTS OF FARM, GARDEN AND ORCHARD But the larvse of possibly the typical portion of the family, embracing the genus Syrphus and its near allies, are entirely predaceous upon plant-lice. Rarely can a colony of plant- lice be found without some of these little enemies hard after them. The adult syrphus-fiy is a very striking insect, with its dark green metallic thorax, and abdomen variously banded with yellow and black. The female fly lays her eggs upon some plant bearing plant-lice. The larvse which hatch from these are elongate, flattened maggots, about one-half an inch long, with hardly a trace of a head, but with four small hooks, which serve as jaws, projecting from the more pointed end of the body. These mag- gots are often of a hght-green color, and so like the color of the plants as to render them most difficult to recognize. The young larvse at once commence crawling over the plant in search of aphids, and as soon as they come in contact with one it is firmly clasped by the small booklets until the juices are sucked from its body. In this manner very large numbers are destroyed, a single maggot of the American Syrphus-fly (Syrphus americanus) having been observed to eat twenty-five apple plant-lice {Aphis pomi) in as many minutes. When the larva is ready to pupate it attaches itself tc a leaf, and the larval skin dries up and forms a case or puparium inside of which the pupa remains until it transforms to the adult fly. Though most of these larvse feed upon plant-lice upon the leaves, one of them, the Root-louse Syrphus-fly (Pipiza radicans)^ Fig. 7. — The root-louse syrphus-fly {Pipiza radicans). a. maggot; 6, puparium; c, fly. (After Riley.) lives entirely underground during that stage, and feeds upon the root-lice of the apple and the grape. None of this family is injurious, and as a large portion of them are so beneficial BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC 13 as frequently to destroy whole broods of plant-lice, they should not be disturbed in their good work if possible to avoid it. The Ground-beetles If, as you scrape away the loose chips at the base of a tree in your door-yard, turn over an old log in the woodland, or pick up a fallen fence-rail, you will scrutinize the inhabitants under these shelters, a number of shining black beetles varying in length from one fourth to 1^4, inches will usually be noticed. If the city reader be not so fortunate as to be famiUar with or have access to these hiding-places, he may find large numbers of the beetles Fig. 8. -The fiery ground-beetle {Calosovia calidum). a, beetle; b, c, " the searcher " {Calosoma scrutator). (After Riley.) larva; under any electric arc Ught during the warm summer evenings; for there they are having a sumptuous banquet upon the small flies and moths attracted by the glare. They are rarely seen at large during the day, as they are almost exclusively nocturnal insects, and from their habit of remaining ahiiost entirely in or on the ground they are usually known as " Ground-beetles." As might therefore be inferred, they are exceedingly valuable to the farmer by destroying large numbers of noxious insects which pass a part or all of their existence in the soil. Besides the glossy black forms which are most commonly seen, many are brilliantly marked with gold, green, purple, and iridescent tints. The Fiery Ground-beetle {Calosoma calidum), so called on account of the wing-covers being dotted with bright gold, has 14 INSECT PESTS OF FARM, GARDEN AND ORCHARD many times been of great assistance in helping to rid a corn-field of cutworms. The larvse of this insect are about one inch in length, of a dark brown color, with the skin of a hard, horny- texture like that of the beetle. They have strong, prominent jaws, and at the posterior end of the body is a forked appendage looking much Hke another pair of jaws. It is not only surpris- ing that these larvse will eat so large a number of cutworms as they have frequently been known to do, but that they will dare to attack such a formidable creature fully three or four times as large as themselves, but their assault is sharp and vigorous, and a single larva has often been seen to kill and eat several full-grown cutworms in a short time. Many instances of the good work of this beetle are on record, among which one by the late Professor J. A. Lintner may be cited, where he found /■ them eating large numbers of the corn- ' ^ crambus — sometimes locally known as the corn bud-worm. Another somewhat larger beetle, called by Professor J. H. Comstock " the Searcher " {Calosoma scrutator), and in fact one of the largest of the family, is a brilliant metaUic green, bordered with a dark purplish- blue, and has the good quality of having a very particular appetite, causing it to kill large numbers of cater- pillars, but to eat only part of each. While in the earth as pupsB large numbers of the Colorado potato-beetles are destroyed by members of this family, and Fig. 9. — Lebia gran dis. (After Riley.) Fig. 10. — The murky ground-beetle (Harpalus caliginosus): adult at left; a, larva; b, head of same; c, mandible. (After Riley.) one species, Lehia grandis which is peculiar in that the wing- covers are somewhat abbreviated, thus leaving the tip of the BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC 15 abdomen exposed, has been noticed on the plants eating the eggs and young larvse of this old potato pest. Another valuable species is one called by Dr. Riley the Murkey Ground-beetle (Harpahis caliginosus) . Its larva is of considerable assistance to fruit-growers by eating large numbers of curculio larvse which it secures from the plums after they have fallen to the earth. From a glance at its formidable jaws, Fig. 10 h — c, it is easy to conjecture the fate of many a curculio grub. Thus here again are found some " bugs " that are friends and not foes, worthy of all the protection that can be afforded them, and well repaying such careful observation of their habits as may be bestowed upon them. Insect Parasites Though large numbers of injurious insects are annually destroyed by those which are purely predaceous upon them, many more succumb to those minute forms which live parasitically within them. A few of these parasites be- long to the order Dip- tera, or true flies, but most of them are classed in the order Hymeno- ptera, in which order are also included the saw- flies, ants, wasps, and bees. Of the half-dozen families of hymenopter- ous parasites one of the largest and most bene- ficial is that of the Ichneumon-flies. The illustrations will best show the form and structure of these insects, which the casual observer will hardly be able to distinguish from other famihes of the group. But it will be noticed that the fine veins of the wings vary considerably in the different parasites figured and it is by these that the entomologist is enabled to separate the different groups and often to identify the species at a glance. Both this and the follow- FiG. 11. — Maggots of Pwipla inquisitor, a parasitic Ichneumon-fly, feeding on a cater- pillar which had spun its cocoon and was ready to pupate. 16 INSECT PESTS OF FARM, GARDEN AND ORCHARD ing family are peculiar in having an exceedingly long ovipositor or egg-tube, of which they make a very good use. It is with this extensile tube that the female deftly punctures the skin of some unsuspecting caterpillar, and under it inserts her eggs. In a few days there hatch from these a host of young maggots which feed upon the juices and tissues of the caterpillar, but are seemingly careful to. avoid injuring any of its vital organs, for as soon as the caterpillar reaches its full growth it changes to a pupa, apparently unaffected. When the maggots have reached their full size each spins up a small silken cocoon inside the pupa, entirely filhng up its now dead shell, and instead of a beautiful moth appearing in the spring, a horde of small flies are seen to emerge from round holes in the side of the pupa, or cocoon. Thus laige numbers of such pests as the apple-tree tent-cater- pillar {Malacosoma americana), hagworms, (Thyridopteryx ephemeroeformis) f caterpillars of the swallow-tailed butterflies which feed upon parsley, car- rots, etc., and a host of others, are consumed by members of this family. Those belonging to the genus Ophion are partial to the large American silkworms which produce some of our largest and most beautiful moths, and difficulty is fre- quently experienced in rear- ing a desired number of moths on account of the large per- cent of cocoons parasitized. The species of the family Braconidoe are very similar to those of the preceding one, and contain some equally ben- FiG. 12.— The long-tailed Ophion (Ophion eficial insects, feeding as they maggot; ^^ xipon such pests as the cod- ling moth, webworms, plum- curculio grubs, plant-lice, etc. Some of the more common forms of this family belong to the genus Microgaster, and their small macrurum). a, aduH; 6, enlarged. (After Riley. ^ BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC 17 white cocoons may frequently be seen almost covering one of our large tomato- or tobacco-worms (see page 220 ) , the pupae of which are often known as "horn-blowers." Many mistake these cocoons for the eggs of the worms, and therefore destroy some of their best friends. Though some thus spin their cocoons on the outside of the host, others remain inside of the parasitized insect until the adult fly emerges. Thus dead plant-hce may often be found with a large round hole in the abdomen — the only evidence of where one of these parasites has emerged. The Chalcis-flies, Chalcididoe, which comprise another closely related family, are often exceed- ingly minute insects, sometimes not over one one-hundredth of an inch long. They are generally of a metallic black color, and the usual veins of the wings are almost entirely absent. Many of these flies are parasitic upon plant-lice, while a large number of their larvae live and mature in the eggs of other insects. Very similar to the chalcis-flies in the habits of infesting plant-lice and insect eggs are some even smaller insects — in fact the small- est known, the largest being rarely over one-twenty -fifth and the smallest only six-or- seven one-thousandths of an inch in length — with a cor- respondingly tremendous and unpronounceable name, known to science as the Pro- dotrypidoe. During the last half century the American farmer has been compelled to contend with an increas- ing number of insect pests. Fig. 13. -A plant-louse parasite (Aphidius ^_ ^ ' afe«ap«is), showing above the parasitized which now and then have louse from which it has issued. (Copied become veritable scourges. ^^°^ '^- Smith.) Every now and then we hear of communities assembling for prayer and fasting to appease the Almighty, whose wrath has hurled a new insect plague against them, but such a procedure is by no means as 18 INSECT PESTS OF FARM, GARDEN AND ORCHARD common as formerly, and little reflection will show that these scourges are entirely due to natural causes. In fact they are very largely brought about by man himself. Some of these pests are due to the fact that in trying to subdue nature by clearing and cultivat- ing the land, man has deprived the insects of their natural food plants. They must, therefore, needs feed upon that which is sub- stituted by him, and as it is less abundant than the former wild vegetation, the number of insects and the injury they inflict are more apparent. By far the larger number of our worst pests, however, are those which come to us from foreign shores. Foreign insects are con- stantly being imported in one way or another, sometimes being already established pests in other lands and sometimes only be- coming so under their new surroundings. These are even more injurious than those native, for whereas many of our native birds, insects, and diseases constantly prey upon native insects and thus keep their numbers in check, the enemies of imported pests rarely accompany them, and they thus increase at an alarming rate and do enormous damage before they are attacked by the natural enemies of similar native pests. It is in the case of these imported pests that the value of parasitic and predaceous insects is most apparent. In an effort to make use of them to fight the gypsy and brown-tail moths in New England, the U. S. Bureau of Ento- mology has for several years been importing large numbers of the parasites and predaceous enemies of these pests and liberating them in affected regions, thus carrying on a practical experiment on a large scale which may show the importance of these parasites in combating imported pests. Even with our native pests, however, we have frequent exam- ples of the value of parasitic and predaceous enemies. Thus the southern grain louse, or "green bug," was soon brought under control by the myriads of little parasites which preyed upon it (see page 140), and these were artificially transported for some distance and liberated in large numbers. Though these efforts at the distribution of this parasite may be open to some question as to their effectiveness, other parasites have been successfully BENEFICIAL INSECTS, PREDACEOUS AND PARASITIC 19 distributed, and there can be no question that before long we shall come better to understand how we may make use of these valuable allies, and some day we may be able to duplicate the apparent miracle by which Dame Nature sweeps away an insect plague in a few days with the aid of these apparently insignificant parasites. CHAPTER III STRUCTURE AND DEVELOPMENT OF INSECTS The more experience the farmer has with insect pests, the more he comes to realize that if he would successfully combat them he must have a certain amount of knowledge concerning their structure and growth. In general, the artificial means which may be effectually used to combat an insect pest will depend more or less upon the anatomical structure of the insect, while control by general methods of culture will depend upon a knowledge of the peculiari- ties of its life-history. The value of a proper understanding pf these important factors in insect control is therefore apparent. General Structure of an Insect The body of an insect is composed of three separate parts the head, thorax, and abdomen (Fig. 14), each of which is com- posed of several rings or segments. To the head are attached the jointed antennae, or feelers, the compound eyes, and the mouth- parts, which are described below. Each of the three segments of the thorax bears a pair of legs, and adult insects usually possess one or two pairs of wings upon the last two segments of the thorax. The abdomen is com- ^ , , ^^ , , . , posed of nine or ten segments, fiiG. 14. — Honev-bee, showing the i , , , three principal regions of the body but bears no appendages save of an insect :—/i, head; . A. Bureau of Entomology.) 93 3.^Dusty-f urrow. trap. 94 INSECT PESTS OF FARM, GARDEN AND ORCHARD dragging a heavy log back and forth in the furrow, making the side next the corn as steep as possible.* In attempting to climb this barriar, the dust will slide from under the bugs and large numbers will accmnulate in the bottom of the furrow, where they will be killed by the heat of the soil if it has a temperature from 110° to 120° (air temperature of over 90°). Keep the furrow clean by dragging a log through it now and then. Sink post-holes a foot deep every few feet in the bottom of the furrow and the bugs will collect in them and may be crushed or killed with kerosene. Such a dust furrow will be of no value in showery weather, and is most effective in hot dry weather on light soil; it may often be used to advantage in com- bination with the following methods. In place of the dust furrow or in combination with it, a strip of coal tar is often run around the field. The strip, which should be about the size of one's finger, can be made by pouring from a watering can with the mouth stopped down, and should be run inside the dust furrow and with post-holes sunk along its outer edge. Sometimes it is rmi in a zig-zag line with the holes at the inner angles so that the bugs will be concentrated at the holes. These tar strips must be freshened whenever dust or rubbish covers them. The soil may be prepared for the tar strip by plowing a back furrow and packing the top with a roller or beating it hard with spades; or a strip of sod may be prepared by scraping away the grass with a farm scraper and then smooth- ing carefully with shovels or hoes; or a dead furrow may be run and the tar strip run on the smooth bottom. To maintain such a tar strip for four weeks costs about $2 a mile and has proven itself entirely practical and effective. if the bugs have already become numerous in the outer rows of corn, most of them may be destroyed by spraying with kerosene emulsion (see p. 44) made to contain four per cent kerosene, apply- ing it in the early morning or towards night. It costs 65 cents a barrel diluted, and a man will spray five acres per day, using a . , * Such a furrow'^may possibly be made more readily by plowing several iurrows and harrowing the ground thoroughly until reduced to a fine mulch and then plowing a dead furrow through the middle, and then dragging this with a log, making the sides as steep as possible. With such construction the furrow will cost about five cents per linear rod. INSECTS AFFECTING GRAINS, GRASSES, ETC. 95 barrel per acre. Whale-oil soap, one-half pound to the gallon of water, has proven equally effective and cost $2.00 per barrel. A blast torch, for which an attachment is furnished with many of the compressed-air sprayers, may be used to advantage for destroying the bugs in a dust furrow or along the tar line, or a spray of pure kerosene or crude petroleum may be used for the same purpose. Extensive experiments have been made in Illinois and Kansas with the use of the muscardine fungus * against the chinch-bug. Though occasionally the results seem to be profitable, and though it is undoubtedly effective in wet seasons and it may be well to distribute the fungus to places where it does not occur so that it may reduce the numbers of the bugs in wet seasons, it seems to be of very little value in dry seasons, when the injury is worst, and cannot be relied upon to check the increase of the pest when used according to the methods so far devised. When chinch-bugs become abundant and their migration to corn seems imminent, the farmer should prepare to devote himself and as many hands as necessary to fighting them until their advance is checked, for delay will mean ruin, while the prompt use of the above methods will save the corn crop. Grasshoppers or Locusts t Plagues of destructive locusts — or what we Americans call grasshoppers — have been recorded since the dawn of history. In America the worst devastation was done by the flights of the Rocky Mountain or Migratory Locust (Melanoplus spretus Thos.), which swooped down upon the States of the western part of the Mississippi Valley in the years 1873 to 1876 in destruc- tive clouds. The Rocky Mountain Locust Let us first consider the species which has been the most injurious, as the other locusts differ from it in but few essential points other than in being non-migratory. To understand correctly its habits the reader should first divide the area which this species affected into three parts. Of *Sporotrich um globuliferum. t Various species of the family Acrididoce. See W. R. Walton, Farmers' Bulletin 747, U. S. Dept. Agr. 96 INSECT PESTS OF FARM, GARDEN AND ORCHARD these (1) the Permanent Region, which included the highlands of Montana, Wyoming, and Colorado, formed the native breeding- grounds, where the species was always found in greater or less abundance;* (2) the Subpermanent Region, which included Man- itoba, the Dakotas, and western Kansas, was frequently invaded; here the species might perpetuate itself for several years, but disappeared from it in time; (3) the Temporary Region, which included the States bordering the Mississippi River on the west, was that only periodically visited and from which the species generally disappeared within a year. Spread — When for various reasons the locusts became excess- ively abundant in the Permanent Region they spread to the Subpermanent Region, and from there migrated to the Tem- porary feeding-grounds. It was the latter area which suffered most severely from their attacks, but, fortunately, they did not do serious injury the next year after a general migration. In the Subpermanent Region their injuries were more frequent than in the Temporary, but were hardly as severe or sudden as farther east. Migrating from their native haunts, flights of the grasshoppers usually reached southern Dakota in early sum- mer, Colorado, Nebraska, Minnesota, Iowa, and western Kansas during midsummer, and southeastern Kansas and Missouri Fig. 73. — Rocky Mountain locust; adult and different stages of growth of young. (After Riley.) during late summer, appearing at Dallas, Texas, in 1874, and aboiit the middle of October, and even later in 1876. As thus indi- cated, the flights were in a general south to southeasterly direction, while west of the Rockies they descended to the more fertile valleys and plains, but without any such regularity as eastward. While the rate of these flights was variable and entirely dependent upon local weather conditions, twenty miles per day was con- * Bull. 25, U. S. Dept. Agr., Div. Entomology. C. V. Riley. INSECTS AFFECTING GRAINS, GRASSES, ETC. 97 sidered a fair average. The flights were more rapid and more distance was covered in the early part of the season, when, while crossing the dry prairies, a good wind often enabled them to cover 200 to 300 miles in a day. As they first commenced to alight in their new feeding-grounds their stay was limited to but two or three days, but later in the season it was considerably lengthened, and, after a section was once infested, swarms were seen to be constantly rising and dropping during the middle of the day. Life History. — Over all the infested area, and while still sweep- ing it bare of crops and vegetation, the females commence to lay their eggs, and continue to deposit them from the middle of August until frost. For this purpose '' bare sandy places, especially on Fig. 74. — Rocky Mountain locusts: a, a, a, females in different positions, ovipositing; h, egg-pod extracted from ground, with end broken open; c, a few eggs lying loose on ground; d, e, showed the earth partially removed, to illustrate an egg-mass already in place and one being placed;/, shows where such an egg-mass has been covered up. (After Riley.) high, dry ground, which is tolerably compact and not loose," are preferred. " IMeadows and pastures where the grass is closely grazed are much used, while moist or wet ground is generally avoided." In such places the female deposits her eggs in masses of about thirty. These are placed about an inch below the surface in a pod-like cavity, which is lined and the eggs are covered by a mucous fluid excreted during oviposition. From two to flve hours are required for this operation, and an average of three of these masses is deposited during a period of from six to eight weeks. 98 INSECT PESTS OF FARM, GARDEN AND ORCHARD As the time of ovipositing varies with the latitude, so the hatching of the eggs occurs from the middle or last of March in Texas till the middle of May or first of June in Minnesota and Manitoba. Until after the molt of the first skin, and often till after the second or third molt, the young nymphs are con- tent to feed in the immediate vicinity of their birth. When the food becomes scarce they congregate together and in solid bodies, sometimes as much as a mile wide, march across the country, devouring every green crop and weed as they go. During cold or damp weather and at night they collect under rubbish, in stools of grass, etc., and at such times almost seem to have disappeared; but a few hours of sunshine brings them forth, as voracious as ever. When, on account of the immense numbers assembled together, it becomes impossible for all to obtain green food, the unfortunate ones first clean out the under- brush and then feed upon the dead leaves and bark of timber- lands, and have often been known to gnaw fences and frame buildings. Stories of their incredible appetites are legion; a friend informs me that he still possesses a rawhide whip which they had quite noticeably gnawed in a single night! As the nymphs become full grown they are increasingly subject to the attacks of predaceous birds and insects, insect parasites, fungous and bacterial diseases, and are also largely reduced by the cannibalistic appetites of their own numbers. When the mature nymphs transform to adult grasshoppers and thus become winged, large swarms are seen rising from the fields and flying toward their native home in the Northwest. This usually takes place during June and early July in the North, and as early as April in Texas, so that it is frequently impos- sible to distinguish the broods of the temporary region from the incoming brood which has migrated from the permanent region. Although the eggs for a second brood are sometimes laid, these seldom come to maturity, and the species is essentially single- brooded. The Lesser Migratory Locust Besides the Rocky Mountain locust there is only one other species that truly possesses the habit of migrating, though to a far lesser extent, and which is therefore known as the Lesser Migratory Locust {Melanoplus ailantis Riley). It is considerably INSECTS AFFECTING GRAINS, GRASSES, ETC. 99 smaller than its western relative and somewhat resembles the red-leggecl locust both in size and appearance. The species is very widely distributed, occurring from Florida to the Arctic Circle east of the Mississippi, and on the Pacific slope north of the fortieth parallel to the Yukon. The habits and life history of the species are in all essentials practically the same as the former species, except that they have no particular breeding- grounds. Injuries b}^ this grasshopper were first noticed in 1748, almost seventy-five years before the first record of the Rocky Mountain locust, and since then it has done more or less serious damage in some part of tlie territory inhabited every few years. Non-Migratory Locusts There are several species of locusts which, though lacking the migratory habit, and thus being more easily controlled, often become so numerous as to do serious damage over limited areas. Both as regards the regions inhab- ited, and its habits, life history, the ^ „^ x^ , , , , ^ ,, ' ^;^' Fig. 75. — Red - legged locust common Ked-legged Locust {Melan- (Melanoplus femur -ruhrum oplus femur-riibrumllsir.) hardly dif- Harr.). (After Riley.) f ers from the last species, and is often found in company with it. It is non-migratory, however, and though the damage it does is thus entirely local, it is often of considerable importance. Records of locust plagues in California date back as far as 1722. Many of them were doubtless due to the California Devastating Locust (Melano- plus devastator Scud.), and in the last invasion of 1885 this species outnumbered all others seven to one. Resembling the last two species in size and markings, the habits and life Fig. 76. — The pellucid locust (Camnula history of this species are also pellucida Scud.). (After Emerton.) g^pposed to be similar tO them, though they have not as yet been thoroughly studied. Together with the last species the Pellucid Locust (Camniila pellucida Scud.) has been largely responsible for the losses occa- 100 INSECT PESTS OF FARM, GARDEN AND ORCHARD sioned by locusts in California, and has also been found in New England, but is not noted there as especially destructive. Our largest winged American Locust, the American Acridium (Schistocerca americana Scud.), is practically confined to the Southern States from the District of Columbia to Texas, and thence south through Mexico and Central America, being rarely found in the North. This species is essentially a tropical one, and has often been exceedingly destructive, being especially so in 1876 in Missouri, Tennessee North Carolina, Georgia, and southern Ohio. Considerably larger than the preceding species are the Dif- ferential Locust (Melanoplus differentialis Thos.) and the Two- Fig. 77. — The American acridium (Schistocerca americana Scud.). (After Riley.) striped Locust (Melanoplus bivittatus Scud.), of which the former is peculiar to the central states of the Mississippi Valley, Texas, New Mexico, and California, while the latter has a more extended range from Maine to Utah and as far south as Carolina and Texas. These two differ from the smaller species in laying only one or two masses of eggs, and the eggs of dif- ferentialis have often been found placed under the bark of logs, but otherwise their habits are very similar. The two-striped locust is characterized by two yel- FiG. 78. — The Two-striped locust (Mela- noplus bivittatus Scud.) . (After Riley. lowish stripes extending from the eyes along the sides of the head and thorax to the extremities of the wing-covers, and is' probably the species most commonly observed by the farmer. INSECTS AFFECTING GRAINS, GRASSES, ETC. 101 The Differential Locust. — Throughout the Mississippi Valley from Illinois southward, the Differential Locust is one of the most Fig. 79. — The differential locust (Melanoplus differentials Thos.). (After Riley.) common and destructive grasshoppers, and is an excellent example of several of our more abundant and injurious species which have very similar habits. Fig. 80. — The southern lubber grasshopper (Dictyophorus reticulatus) : njTnph and adult, slightly enlarged. The little grasshoppers hatch about the middle of May, from eggs which were laid in the fall, though we have observed them in March in Central Texas, and are of a dusky brown color, marked with yellow. The head and legs are the most prominent feature of the young nymphs. During their sub- sequent growth they molt five times at intervals of ten days to two weeks, the relative size and ap- pearance of the different stages being shown in Fig. 82. Fig. 81. — Egg-mass of the differential locust — enlarged. 102 INSECT PESTS OF FARM, GARDEN AND ORCHARD Fig. in all The hoppers become full grown bout the first of July. The adult is about 1| inches long, its wings expand 2| inches, and it is of a bright yellowish-green color. The head and thorax are olive-brown, and the front wings are of much the same color, with- out other markings, but with a brownish shade at the base; the hind-wings are tinged with green; the hind-thighs are bright yellow, especially below, with four black marks; the hindshanks are yellow with black spines and a ring of the same color near the base. The adults at once attack what- ever crops are available, often finishing the destruction of those injured by them as nymphs, but in a few days their appetites seem to become somewhat appeased and they com- mence to mate and wander in search of suitable places for laying the eggs. Rela- tively few eggs are laid in cultivated ground, the favor- ite places being neglected fields grown up in grass and weeds, the edges of culti- vated fields, private road- ways, banks of ditches and small streams, and pasture lands. Alfalfa land is a fa- vorite place for oviposition, and alfalfa is frequently ^,?;;r~^y™P'^^ °^ *^® *^^^^^^*^^^ ^°^^^*^ seriously injured by this different stages (1 to 5) of growth — • tx • i i .^i i enlarged. species. It IS doubtless due INSECTS AFFECTING GRAINS, GRASSES, ETC. 103 to these egg-laying habits and the abundance of food on unculti- vated land that this species always increases enormously on land which has been flooded and then lies idle for a year or two. Fig. 83. — A Locust-mite (Trombidium locustarum): a, the larva as seen on locust's wing; c, male mite; d, female, the two latter appearing as when egg-destroyers — all greatly enlarged. (After Riley.) Most of the eggs are laid in August and early September. Each female deposits a single egg mass of about 100 eggs just beneath the surface of the soil. During this season the females may frequently be found with the abdomens thrust deep in the soil, as the process of egg-laying re- quires some time. The eggs are yellow and arranged irre- gularly in a mass which is coated with a gluey sub- stance to which the earth adheres, which protects them from variable -^ „. . „ ■ .. a t . Fig. 84. — Anmo?n?/ia egg-parasite, a, fly, o, puparium; conditions of mois- c, larva; d, head of larva. (After Riley.) ture and temperature. Enemies. — As before mentioned, large numbers of the nymphs are destroyed before reaching maturity by their natural enemies. Among these a minute fungus undoubtedly kills many of those already somewhat exhausted, especially during damp weather. 104 INSECT PESTS OF FARM, GARDEN AND ORCHARD Almost all of our common bii'ds, as well as many of the smaller mammals, are known to feed quite largely upon them. A small red mite {Tronibidium locustarum Riley), somewhat Fig. 85. — ^Two tachina-flies. (Exorista Icucanice Kirk, and Riley.) (After Riley.) flavicauda resembling the common red spider infesting greenhouses, is often of great value not only in killing the nymphs by great numbers of them sucking out the life-juices of the young hopper, but also in greedily feeding upon the eggs. The maggots of several species of Tachina-flies are of consider- able value in parasitizing both nymphs and adult locusts. Their eggs are laid on the neck \[ of a locust, and, upon hatching, the maggots pierce the skin and Fig. 86.— Common flesh-fly {Sarco- jjyg inside by absorbing its juices phaga carnana Lmn.): a, larva; o, pupa; c, fly. Hair-lines show natural and tissues. When tuU grown size. _(After Riley.) the maggots leave the locust, descend into the earth, and there transform to pupae inside of their cast skins, and from the pupse the adult flies emerge in due time. The maggots of one of the Bee-flies {Systcechus oreas) feed upon grasshopper eggs, but their life history is not fully known. The common Flesh-fly (Sarcophaga carnaria Linn.), Fig. 86, is also very destructive, though largely a scavenger. But of all the insects attacking locusts, the Blister-beetles, which, unfortunately, are often known to us as very injurious to various garden crops, are probably of the most value. The female beetle deposits from four to five hundred of her yellov/ish eggs in irregular masses in loose ground, and in about ten days INSECTS AFFECTING GRAINS, GRASSES, ETC. 105 there hatch from these eggs some " very active, long-legged larvae, with huge heads and strong jaws, which rmi about everywhere seeking the eggs of locusts," Each of these larvae will consume one of the masses or about thirty eggs. The subsequent life his- tory of these insects is very complicated on account of their pecu- liar habits, but the various stages are shown in Fig. 87. Control. — As the eggs are usually laid in the ground in the fall, deep plowing in late fall or early spring effectuallv buries (^^c^o, ""^^ "-mj "'^wc -^"^^ Fig, 87. — Various stages of a blister-beetle (EpicatUa vittata). (After Riley.) them too deep for the young nymphs to emerge. On alfalfa land thorough disking is often used for the same purpose. Thorough harrowing in the fall so as to pulverize the soil for the depth of an inch will break up many of the egg masses, though it is not as sure a control as plowing them under. When the young emerge, they may sometimes be destroyed by burning over stubble, grass and rubbish where it is present in sufficient quantities, or by augmenting it with straw, which may be done to advantage on cold days when the nymphs are congregated in such shelter. If the surface of the ground is smooth and hard many may be killed by the use of a heavy roller, particularly in the morning and evening, when they are sluggish in their movements. Plowing a badly infested field in a square, working toward the centre so as to drive the young nymphs inward, will result in burying many of them in the furrows, and the last may be burned or trapped in holes as described below. Simple ditches 2 feet wide and 2 feet deep form effectual barriers for the young hoppers. The sides next to the crop to be protected should be kept finely pulverized by hauling a log or a brush of dead branches through the ditch. The ditch may be made as described for chinch-bugs and is handled in the same manner, the little hoppers drifting to the bottom of the ditch, where they are killed by the heat on a hot day or YiG. 88. — Two hopperdozers, tied together, at work. (After Lugger, Bull. 43, (Minn. Agr. Exp. Sta.) 106 INSECTS AFFECTING GRAINS, GRASSES, ETC. 107 where they are caught in post-holes sunk every few feet in the bottom of the ditch. This method may be used to advantage in plots of corn, cotton, or garden truck which has already become infested, by running furrows around the field and occa- sionally through it, and then driving the young hoppers toward them, which may be readily done by a number of children armed with branches. Where ditches containing water are available the young hoppers may be very effectively destroyed by oiling the surface of the water with kerosene emulsion and then driving Fig. 89. — Hopperdozer with cloth back, showing construction. (After W. R. Walton, Farmers' Bulletin 747, U. S. Dept. of Agriculture.) them into the ditches, for even if they succeed in crawhng out they will succumb to the oil. In pastures, small grains or any crops permitting their use, immense numbers of the nymphs ma}^ be caught by the use of hopperdozers, which may be utilized where the use of poisoned bran would not be possible. The hopperdozer consists of a shallow pan containing water with a surface of kerosene, crude petroleum, or coal tar, which is sometimes used without water. The pan is mounted on runners or wheels and if larger than about 3 feet square is usually provided with partitions to prevent slopping. The back and sides are high and sometimes are made of canvas. "A good cheap pan is made of ordinary sheet iron, 8 feet long, 11 inches wide at the bottom, and turned up a foot 108 INSECT PESTS OF FARM, GARDEN AND ORCHARD high at the back and an inch high in front. A runner at each end, extending some distance behind, and a cord attached to each front corner, complete the pan. We have known of from seven to ten bushels of young locusts caught with one such pan in an afternoon. It is easily pulled by two boys, and by running several together in a row, one boy to each rope, and one to each contiguous pair, the best work is performed with the least labor." Larger pans are drawn or pushed by horses. The oil is best used on the surface of water, from which the insects are removed with a strainer, and any which hop out will die after having come in contact with the oil. Destroying the Adults. — The destruction of the winged insects is an entirely hopeless task, for, though even large numbers Fig. 90. — ^The Price oil-pan or hopperdozer, with partitions to prevent slopping. (After Riley.) are caught, so many will remain that the damage done the crops would be but very slightly diminished. One of the most promising means for preventing the swarms of winged migratory locusts from alighting in the fields is by a dense smudge, in which some foul-smelling substances are placed. Where strictly attended, and with favorable winds, this has often proved highly successful. To accomplish the best results farmers over an extensive area should combine in its use. INSECTS AFFECTING GRAINS, GRA.SSES, ETC. 109 The South African Fungus. — In 1900 Professor Morgan made a test of a fungous disease which had been found to destroy large numbers of grasshoppers in South Africa, to determine whether, after starting it by artificial propagation, it would spread suffi- ciently to destroy any considerable number of locusts The weather was favorable, rains being frequent. Early in August it was found that " over the areas where the liquid infection Fig. 91. — Carolina locust killed by fungous disease. (Photo by Weed.) was spread diseased hoppers were abundant." "As many as a dozen dead grasshoppers could be found upon a single plant, and some upon nearly every weed on ditch-banks where grass- hoppers were numerous. From the centres of infection great areas had become inoculated, spreading even beyond the planta- tions first infected." The property upon which it was placed became thoroughly infected with the fungus. Strangely, though many other species of grasshoppers were abundant, only the differential locust was killed by it. Dr. Howard states that this disease has also spread and done effective work in Colorado. However, more recent experiments made by the writer in Texas gave only negative results, and it is doubtful if any reliance can be placed upon the artificial use of such fungous diseases for locust control. Poisoning. — A mash composed of bran, molasses, water, and some form of arsenic, flavored with fruit juice according to formula given on page 57, has been extensively used for grasshoppers 110 INSECT PESTS OF FARM, GARDEN AND ORCHARD especially during the outbreaks of more recent years in Kansas and neighboring states. Preparation of the poison is frequently under the direction of the county agent and the Experiment Station representatives and the distribution is a community or even a county problem, in some cases poisoning being required by local ruling. Tons of paris green have been used in a single county in one year during a serious outbreak and the result has well re- paid the expense and labor. A substitute which has been used considerably is the Criddle mixture, prepared by poisoning about 100 pounds of fresh horse manure with one pound paris green and using it in the same manner as the bran mash. The poisoned bran mash is now regarded as the most effective means for the control of all grasshoppers which are commonly injurious. The Army Worm * Almost every year some locality reports serious injury to crops by armies of caterpillars, which have not been previously known for many years. This being the case the farmers are at a loss for means to combat them, and by the time the in- formation has been secured the pests have completed the damage. The Army Worm occurs through- out the United States east of the Rocky Mountains and lives in low, rank growths of grass, which form thenormal breeding-grounds. When from an abundance of such food, or through failure of the parasitesto prevent their increase, the caterpillars become over- Fig. 92.-Army-worm moth (Ctrp/^^^^ abundant, they assume the army limpuwcto), pupa, and eggs in natural ""^ ' '' J position in a grass-leaf. Natural habit and march en masse, con- size. (After Comstock.) suming all in their path. The next year their natural enemies will usually have them under control again and there will be but Httle damage, and then they will not be observed as injurious for a series of years, though the moths are always fairly common. * Cirphus unipuncta Haworth. Family Noduidoe. Fig. 93.— Army-worms at work on corn-plant. (After Slingerland.) Ill 112 INSECT PESTS OF FARM. GARDEN AND ORCHARD Life History. — In the North the moths appear early in June and the females lay the small yellowish eggs in rows of from ten to fifty in the unfolded bases of the grass leaves, covering them with a thin layer of glue. Over seven hundred may be deposited by one female, so that when the young caterpillars hatch, in about ten days, the progeny of a few moths might form a quite destructive army. The worms usually feed entirely at night, and thus whole fields will sometimes be ruined before they are discovered, though a few generally feed by day, as they all do in cloudy weather. The leaves and stalks of grains and grasses form their favorite food, the heads usually being cut off, but various garden crops are often seriously injured if they happen in their path. Though usually untouched, even clover is not exempt. In from three to four weeks the worms have become full grown and are then about 1| to 2 inches long, of a dark gray or dingy black color, with three nar- row, yellowish stripes above, and a slightly broader and darker one on each side, quite resembling cutworms, to which they are nearly related. They now enter the earth and transform to pupae, from which the adult moths emerge in about two weeks. These lay eggs for another brood of worms which appear m September, but are very rarely injuri- ous. The moths which de- velop from this last brood either hibernate over winter or deposit eggs, the larvsB from which become partially grown before cold weather and then hibernate. In either case the young larvai feed in the spring, not usu- ally doing much damage, pupate in May, and the moths of the first genera- tion appear in June as already described. Thus in the North there are three Fig. 94. — An army w o r m — a bout one-third en- larged. (After Chittenden, U. S. Dept. Agr.) Fig. 95. — a, head of fall army worm; b, head of army worm — enlarged. (After Chittenden, U. S. Dept. Agr.) INSECTS AFFECTING GRAINS, GRASSES, ETC. 113 broods a year, the young larvae usually hibernating, while in the South there may be as many as six generations, and the moths usually hibernate over winter and lay their eggs in the spring. The moths very often fly into lights and are among the com- monest of our plain " millers." The front wings are a clay or fawn color, specked with black scales, marked with a darker shade or stripe at the tips, and with a distinct spot at the centre, which gives the specific name unipunda. The hind-wings are somewhat hghter with blackish veins and darker margins. Enemies. — Were it not for other insects which pray upon the army-worm, the army habit would doubtless be more often assumed and we should have to deal with them more frequently. Ordinarily, however, the parasitic and predaceous insects hold Fig. 96. — The farmer's friend, the red-tailed tachina-fly (Winthemia 4-pustu- lata): a, natural size; b, much enlarged; c, army worm, on which fly has laid eggs, natural size; d, same, much enlarged. (After Slingerland.) them in check very efficiently and when an outbreak does occur, the later broods of the same season are often entirely destroyed by their insect enemies. Large numbers are always destroyed by the predaceous ground-beetles and their larvae (p. 13), but their most deadly enemies are the tachina-flies (p. 104) These lay from a dozen to fifty eggs on a caterpillar, and the maggots from them enter the body and absorb the juices and tissues of the host, thus soon killing it. When feeding at night the worms 114 INSECT PESTS OF FARM, GARDEN AND ORCHARD are ordinarily free from these parasites, but when the marching habit is assumed the flies swarm around them on cloudy days and before the next year they again have the remnants of the voracious army under subjection. Therefore, worms with the tachina-fly eggs on them (Fig. 95) should never be destroyed where avoidable. Control. — When detected, all efforts should be centred on keeping the worms out of crops not yet attacked and confining their injury to as small an area as possible. As a barrier to their progress, there is nothing better than a dust furrow made as already described for chinch-bugs (p. 92), two or three of which may be found necessary in cool weather or where a fine dust can- not be maintained Deep fall plowing and thorough harrowing will be effective against the hibernating larvse, as will the burning of all grass along ditches, fences, and spots where the larvse normally five. By thorough spraying, or perhaps better by dusting, a strip of the crop with Paris green or some arsenical, and liberally distributing poisoned bran mash (see p. 57), large numbers may be destroyed. Where they are massed in furrows they may be destroyed by spraying them with pure kerosene or crude petroleum. As in fighting chinch-bugs the army worm must be given immediate and conclusive combat if the loss of crops is to be prevented, for they move rapidly and destroy all in their path. The Fall Army Worm or Grass Worm * Though somewhat the same in its habits as the true army- worm, the Fall Army Worm is so called because it appears later in the season, the former species being rarely injurious after August 1st. It is also more omnivorous, for while the army- worm prefers grasses, and grains, the fall army-worm feeds upon a large variety of crops, includmg sugar-beets, cow-peas, millet, sweet potatoes, and many other forage and truck crops. In Nebraska and the Central West it is a serious pest of alfalfa and is called the Alfalfa Worm. It is also sometimes very de- * Laphjgma frugiperda S. and A. Family Noduidce. See Farmers' Bulletin 752, U. S. Dept. of Agriculture. Walton and Luginbill. INSECTS AFFECTING GRAINS, GRASSES, ETC. 115 structive to lawns, as was the case in Chicago in 1899. The fall army-worm is more of a native of the Southern States, but occurs from Canada to the Gulf and west to the Rockies. At first glance the caterpillars have much the same general appearance as the army worm, but closer examination reveals marked differences. Along each side of the body is a longitudinal pitch-colored stripe, and along the middle is a yellowish-gray stripe about twice as wide, which includes four black dots on each segment. The caterpillars assume the habit of working in armies, but usually do not feed in such large numbers as the true army worms and thus are more difficult to combat. Life History. — The winter is passed in the pupal state, the pupae being about one-half inch long and being found in cells one-quarter to one- half an inch below the sur- face. The moths emerge in the spring and the females lay their eggs on grass in clusters of fifty or more, each mass being covered with the mouse-colored hairs from the body of the female. The eggs hatch in about ten days and the caterpillars are found during May and June. The complete life history of the insect has not been care- fully followed, but it seems probable that there are but two complete generations in the North, three generations in the latitude of central and southern Illinois and the District of Columbia, and four in the extreme South. In any event, the destructive brood of cater- pillars appears in August and early September. The parent moth is of a "general yellowish, ash-gray color, with the second pair of wings almost transparent, but with a purplish reflection. In extent of wings it measures about Ij inches, and when closed the length of the insect is about three- FiG. 97. — The fall army-worm: a, moth, plain gray form; h, fore wing of Pro- denia-like form; c, larva extended; d, abdominal segment of larva, side view; e, pupa; d, twice natural size, others enlarged one-fourth. (After Chittenden, U. S. Dept. Agr.) 116 INSECT PESTS OF FARM, GARDEN AND ORCHARD quarters of an inch. The front wings are mottled or marbled, especially near the central area, and usually there is visible a fine white line a short distance from the edge and parallel to it. The hind-wings have a fringe of darker hair as well as veins that contrast somewhat with the lighter portion " (Fig. 97). Control. — Deep fall plowing and thorough harrowing will break up the pupal cells and thus largely prevent the develop- ment of the spring brood of moths. In perennial crops like alfalfa thorough disking may be used and on lawns deep raking with a long-toothed steel rake will kill many of the pupae. In fields of young grain and on lawns many of the caterpillars may be killed by a heavy roller. When not present in too large numbers, the worms may be destroyed by spraying the food plants with Paris green, arsenate of lead or other arsenicals, or by the use of poisoned bran mash. When present in large numbers and the army habit is assumed they should be com- bated the same as the army-worm. CHAPTER VIII INSECTS INJURIOUS TO SMALL GRAINS * The Hessian Fly f The Hessian fly is much the most destructive of the insects attacking wheat, to which its injury is practically confined; for though it occasionally injures barley and rye, it has never Fig. 98. — ^The Hessian fly {Mayetiola destnictor): a, female fly; 6, flaxseed stage or pupa; c, larva; d, head and breast-bone of same; e, pupa; /, puparium; g, infested wheat-stem showing emergence of pupse and adults. (After Marlatt, U. S. Dept. Agr.) been reared on other grains or grasses. Its name was received from the fact that it was first noticed on Long Island in * Mayetiola destructor Say. Family Cecidomyiidce. t See "The Principal Insect Enemies of Growing Wheat," C. L. Marlatt, Farmers' Bulletin No. 132, U. S. Department of Agriculture. 117 118 INSECT PESTS OF FARM, GARDEN AND ORCHARD 1779, near where the Hessian troops had landed three years before. It now occurs over the main wheat-growing area of the eastern United States between parallels 35° and 45° westward to the 100th meridian, on the Pacific coast, in Canada, and in many other parts of the world where wheat is grown. Not infrequently it destroys 25 to 50 per cent of the whole crop in some localities, and it has been estimated that 10 per cent of the crop of the whole country is lost from its ravages. Life History. — The adult flies are little dark-colored gnats about one-tenth inch long, so small as to escape common observation. Each female lays 100 to 150 minute reddish eggs, one-fifteenth inch long, placing them in irregular rows of from three to five or more,* usually upon the upper surface of the leaves. In a few days these hatch into small, reddish maggots, which soon turn white, are cylindrical, about twice as long as broad and have no true head or legs. The fall brood mag- gots burrow be- neath the sheath of the leaf and its base, causing a slight en- largement at the point of attack, but in the spring they usually stop at one of the lower joints, in both instances becoming fixed in the plant, absorbing its sap and destroying the tissues. The first indications of the work of the maggots on winter wheat in the fall are the tendency of the plants to stool out, the dark color of the leaves and the absence of the central stems. Later many of the plants yellow and die. The spring maggots attack the laterals, or tillers, which have escaped the previous brood, Fig. 99. — The Hessian fly,fadult male — greatly en- larged. (After Marlatt, U. S.Dept. Agr.) INSECTS INJURIOUS TO SMALL GRAINS 119 so weakening them that the stems break and fall before ripening and cannot be readily harvested. About four weeks after hatching the maggots are full grown, and are greenish-white and about three-sixteenths inch long. The skin then turns brown, shrivels slightly, and inside it is formed the pupa. This outside case, composed of the cast larval skin, is known as the "pupa- rium," and this stage is commonly called the "flaxseed" from the resemblance to that seed. In this stage most of the fall brood passes the winter, the flies emerging in April or May, while the summer brood remains in the "flaxseed" stage in the stubble during the late summer and emerges when the first wheat is planted in the fall, emerging later far- ther south. Several species of small chalcis flies (page 19) parasitize the larvae and pupae and were it not for their assistance it would doubtless be difficult to raise wheat. As yet no prac- tical method of increasing their abundance has been devised, though colonies have been carried to regions where they were scarce. Cofitrol. — The principal means of avoiding injury by the Hes- sian fly in the winter wheat regions is late planting in the fall. Inasmuch as the flies appear within ^about a week and then dis- FiG. 100. — "Flax-seeds" or puparia of the Hes- sian fly on young wheat — enlarged. (After Pettit.) 120 INSECT PESTS OF FARM, GARDEN AND ORCAHRD appear, if planting be delayed until after that time, but little of the wheat will be injured. Dry weather in late summer and early fall will delay the appearance of the flies, even with normal tem- perature conditions, and the further south, the later they appear. From experiments being conducted by the U. S. Bureau of Ento- mology, Professor F. M. Webster states that the following dates will probably be found safe for sowing wheat in average seasons: in northern Michigan soon after the 1st of September; in southern Michigan and northern Ohio, about September 20th; in southern Ohio after the first week in October; in Kentucky and Tennessee, October 10th to 20th; in Georgia and South Carohna, October 25th to November 15th. The exact time will also depend upon altitude as well as latitude. A rotation of the wheat crop compels the flies when they emerge from the stubble to travel in search of the young wheat plants. Should storms or heavy winds occur, the frail little flies will be de- stroyed in large numbers, whereas if they found wheat immedi- ately available the mortality woifld be small. W Fig. 101. — Hessian fly: a, egg, greatly enlarged; h, section of wheat-leaf showing eggs as usually deposited — less enlarged; c, larva; d, pupa taken from puparium or "flaxseed" — e, c, d, e, much enlarged. (After Webster and Marlatt, U. S. Dept. Agr.) Inasmuch as most of the spring brood remain in the stubble in the flaxseed stage after harvest, if the fields be then burned over, large numbers will be destroyed. This may be done by cut- ting the grain rather high at harvest, and then mowing the weeds and grass and allowing them to dry a few days before burning. INSECTS INJURIOUS TO SMALL GRAINS 121 Unfortunately this practice is often impossible, owing to the prac- tice of seeding wheat land to grass and clover. As early volunteer plants always become badly infested and the pupae wintering on them give rise to a spring brood which attacks the main crop, all volunteer plants should be destroyed by plowing or disking before the larvae have matured. This principle has some- times been utilized in the form of a trap crop, strips of wheat being sown early so as to attract the flies and then being plowed under after the bulk of the eggs had been laid upon them, thus protecting the main crop, planted later. The enrichment of the soil, the preparation of a good seed bed, and the use of good seed, so as to secure a vigorous growing crop, are all of the greatest importance in overcoming injury by the Hessian fly. After the crop is once attacked, no truly remedial measures are known except to apply liberally some quick-acting fertilizer which will cause the plants to tiller freely and give them suflScient vigor to withstand the winter and thus increase the healthy stems the next spring. Of late years the practice in some of the principal wheat growing states, notably in Kansas, has been to plow the wheat stubble under deeply, destroy all volunteer plants and to roll or pack in some manner the soil in the plowed fields so that the adult flies will be unable to make tlieir escape from the buried pupae. This is recommended as the best means of control but may well be practiced along with sowing after the "fly-free" date as deter- mined for the region in question. Some work with immune or partially immune varieties is in progress but no results of a definite nature have been announced. Keeping the soil in first class condition and practicing rotation and other matters of the best farming practice will help to keep the damage from the fly from being so serious during any season as it might otherwise have been. The Wheat Joint-worm * For the last sixty years the joint- worm has been known as a serious pest of wheat throughout the wheat-growing region east of the Mississippi River, the damage varying from a * Harmolita tritici Fitch. Family Chalcididce. See W. J. Phillips, U. S. Dept. Agr. Bulletin 808, and Farmers' Bui-" letin 1006. J 122 INSECT PESTS OF FARM, GARDEN AND ORCHARD slight injury which is hardly noticeable, and which may escape observation for several years, to an almost total infestation of the crop. The adults appear in April, May, or early June, according to the latitude, and are small black, four-winged flies about one-eighth inch long, with the joints of the legs and feet yellow. They look something lilce small, winged black ants (Fig. 102) and curiously enough belong to a family whose members are almost all parasitic on other insects, so that before they had been thoroughly studied they were thought to be parasites of the Hessian fly. The females lay their eggs in the stems, generally selecting the uppermost joints that have ap- peared at that time. " The young worms develop rapidly, each in a little cavity within the straw. Often knots, swellings, and twistings occur in the straw at the point of infestation; again there is little sign of the insect's presence Fig. 102. — a, wheat-straw affected by joint-worm; except a slight discol- h, adult as seen from above. (After RUey.) ^^.^^-^^ ^^ ^ ^^^j^ ^^_ viation of the fibres and grooves of the straw from their natural course. When the infested section is split with a knife it is found to be brittle and woody in character, and contains from 3 or 4 to 20 or more yellowish larvse, about one-eighth inch long when full-grown. These larvae remain in the straw until the following spring, when they issue as adults and commence again the life cycle in the new crop. The damage is done by the worms cut- ting off the sap supply from the head, causing it to become shortened, containing comparatively few kernels, and such kernels as develop are apt to be small and shriveled from lack of nourishment. Also because of the brittleness of the straw high winds are apt to break much of it down." — Gossard. The presence of the pest is always indicated at threshing by short, hard bits of straw, containing the larvae, which are carried INSECTS INJURIOUS TO SMALL GRAINS 123 out with the grain instead of going over in the straw. It has Usually been considered necessary to separate and burn these, but Professor F. M. Webster finds that the larvse in them are probal)ly killed in threshing, as he has been unable to rear z^m^^' Fig. 103. — Swellings made by wheat joint-worms in straw — enlarged. (After Pettit.) adults of either the joint-worm or its parasites from such bits of straw. Control. — A rotation of the wheat crop is of prime impor- tance in the control of this pest, and where wheat is not planted on the same land and is sown as far from that of the previous year as possible there will be but little damage. It is obviovis that the stubble should be plowed u n d e r where possible, or burned during the late fall or winter. Cut infested grain as low as possible so as to remove the larvse in the straw. Fig 1U4- — vv neat straw-worn : adult of fall genera- tion, much enlarged. (After Howard, U. S. Dept. Agr.) Where the stubble cannot be burned, break it down by haiTOwing in the spring and then collect with a hay- 124 INSECT PESTS OF FARM, GARDEN AND ORCHARD rake and burn. Prepare the seed bed thoroughly and fertihze well, when injury is expected, so as to ensure a strong growth and early ripening. Green manure containing infested straw should not be scattered on land to be used for wheat, and all infested straw which has not been used up by April should be burned. The Wheat Straw-worm * " The Wheat Straw- worm," says Professor F. M. Webster, " sus- tains the same relation to winter-wheat culture west of the Miss- issippi River that the joint-worm does to the cultivation of this cereal east of this river. Both, when excessively abundant, occasion losses from siight to total. A wheat stem attacked by the joint-worm may produce grain of a more or less inferior quality and less of it; but the spring attack of the wheat straw- worm is fatal to the plant affected, as no grain at all is produced, and while the second generation of the same has a less disastrous effect in the field, it nevertheless reduces the grade and weight Fig. 105. — Wheat straw-worm a, ventral view; b, side view of larva; c, antenna?; d, mandible; e, anal segment, ventral view; /, adult female; g, fore-wing; h, hind-wing; i, aborted wing. (After Riley.) of the grain." Though the straw-worm occurs over much of the same territory in the East as the joint-worm, it is rarely so injurious. Life History and Description. '\ — " There are two generations * Harmolita grrandzs' Riley. Family Chalcididm. See W. J. Phillips, U. S. Dept. Agr. Bulletin 808. t From Circular 106, Bureau of Entomology, U. S. Dept. Agr., by F. M. Webster and Geo. I. Reeves. INSECTS INJURIOUS TO SMALL GRAINS 125 of the insect annually, the adults of the first generation differing considerably in appearance from those of the second. To the farmer they will all look like minute or large, shining black ants, with or without wings, their legs more or less banded with yellow, and having red eyes. Individuals of the first generation emerge in April from the outstanding straws and stubble. They are very small, most of them are females, and many are wingless. The females deposit their eggs in the young wheat plants, the stems of which at this time extend but little above the sur- face of the ground. The egg is placed in or just below the embryonic wheat head and the larva or worm works within the stem, usually causing a slight enlargement. When the worm is full grown it will be found in the crown of the plant, having eaten out and totally destroyed the embryonic head, its body occupying the cavity thus formed. '' The females which deposit these eggs, being small and fre- quently wingless, are in no way fitted for traveling long dis- tances, The larva or worm is of a very light straw color, indeed almost white, with brown jaws. These worms develop very rapidly and, as they feed rMMli c' on the most nutritious part of the plant, they become robust and larger than those found in the mature straw in late summer. In May the larvse become full grown and pass at once through a short pupal stage. The pupse are at first the same color as the larvae, but later change to a shining jet black, a few days the fully devel- oped insects gnaw circular holes through the walls of the stem and make their way out. These adults are much larger and more robust than the individuals of the first generation and arc provided with fully developed, serviceable wings. That they make good use of Jjj Fig. 106. — The wheat straw-worm: method of oviposition of female of summer form: a, female inserting her eggs; />, section of wheat stem, showing egg; c, and ovipositor, d; c, egg, greatly magnified. (After Riley and Webster, U. S. Dept. Agr.) 126 INSECT PESTS OF FARM, GARDEN AND ORCHARD their wings, and scatter themselves about over fields adjacent to their place of development, is shown by their occmrence in fields of grasses (in the stems of which they do not breed) situated considerable distances from wheat fields. In ovipositing, the females of this generation select the largest and most vigorous- growing stems in wliich to place their eggs. " The adults of the second generation deposit their eggs from early May, in Texas, up to the middle of June, in northern Indiana, or about the time the wheat is heading. Their aim at this time is to place the eggs singly in the growing stem, just above the youngest and most succulent joints, which are not so covered by the enfolding leaf sheaths as to be inaccessi- ble to them. Thus it is that the stage of advance- ment in the growth of the wheat stem at the time of oviposition of the summer generation of females determines whether the larvse will be well upward in the straw, and there- fore removed after har- vest, or lower down and consequently left in the field in the stubble. "The method of ovi- position and the point where the egg is usually formed is shown in Fig. 103. The larva forms no Fig. 107.— "\ gall, nor does it harden the stem within which it develops. There is nor- mally but one larva in each joint; but if several eggs have been placed between joints and produce larvse there will be one in the centre of the stem just above the joint and others in the walls just -Wheat straw-worm, showing point where female of the spring form deposits the egg in young wheat in early spring. Enlarged showing position of egg at right. (After Webster, U. S. Dept. Agr.) INSECTS INJURIOUS TO SMALL GRAINS 127 under the internal wall-covering or inner epidermis. These larvae in the walls of the straw do not, as a rule, kill the stem, but their effect is to curtail the yield by reducing the weight. The larvse develop rapidly and reach their full growth before the straw has hardened. By October, in the Middle West, though earlier in the South, they pass into the pupal stage, in which, as a rule, they remain until early spring, whereupon they develop to adults and gnaw their way out." In the Northwest, where both winter and spring wheat are grown, the injury is particularly severe to spring wheat, as the adults of the second generation from winter wheat oviposit upon it while it is still young and ruin it in much the same way as the first generation does on the winter wheat in spring. Vol- unteer plants which carry the pest over winter have the same effect in increasing the injury to spring wheat. Control. — A rotation of crops which will eliminate the growing of wheat two years in succession on the same land is by all means the most successful and practicable means of control. The adults of the first gene- ration are very small and largely wingless ;,they are unable to migrate Fig. 108.— The wheat saw-fly borer far, so that rotation is exceedingly {Cephus vygmmusUnn)-\a, out- ' . . ° -^ hne of larva, natural size; o, efficacious, though it should be larva, enlarged ;c, larva in wheat- planned SO that wheat is not planted next to stubble land, for the edge will become infested by the first gene- ration, and the second generation will then become distributed throughout the field. The burn- ing of stubble and outstanding straw will be advantageous wherever practicable. Clean fallowing in early summer and the abandonment of spring-wheat culture will reduce injury in the Northwest. stalk, natural size; d, frass; e, adult female; /, P achy oner us cal~ citrator, female, a parasite — en- larged. (After Curits, from "Insect Life.'') 128 INSECT PESTS OF FARM, GARDEN AND ORCHARD Saw-Flies Attacking Wheat * Several members of the Hymenopterous family commonly called saw-flies, are occasionally found feeding on wheat but scarcely deserve to be ranked as pests. One of these is the Wheat Saw-fly Borer, t and another is called the Western Grass-stem Saw-fly. t The former is an importation from Europe while the latter is a native insect and is more common in the Northwest than in the Eastern States. Both species bore in the stems of wheat and some other grass Fig.' 109. — The western grass-stem saw-fly {Cephus occidentalis) : a, larva; b, female saw-fly; c, grass-stem showing work; c, enlarged, a, b, more enlarged. (After Marlatt, U. S. Dept. Agr.) plants. Eggs are laid in the stem and a single larvae develops and feeds within the stem until full grown when it pupates with- in the part of the stem which is underground and there spends the winter. The adults appear about May. Remedies. — Rotation of crops, burning of stubble and plowing the stubble under deeply are the remedies suggested, should any be needed on account of the serious increase of the pests. * Family Tenthredinido'. t Cephus pygma'us I.inn. t Cephus occidentalis, Riley and Marlatt. INSECTS INJURIOUS TO SMALL GRAINS 129 Other species of saw-flies feed on the leaves and even on the heads of wheat. They, like the stem-borers, are rarely abundant enough to be trouble- some. Among these are two species called merely wheat saw-flies (Dolerus arvensis Say and Dolerus collaris Say). These species occur throughout the United States and southern Canada, east of the Rockies. These saw- flies are fairly large, com- pared with the ones pre- FiG. 110. — A wheat saw-fly (Dolerus arvensis . , Say) : female— much enlarged. (After Riley Viously discussed. The and Marlatt, U. S. Dept. Agr.) adults appear as dull black or bluish four-winged flies, marked inconspicuously with Fig. 111. — The grass saw-fly {Pachynemalus exterisicornis Norton): a, a, eggs on wheat-blade; b, young larva?; c, full-grown larva; d, cocoon from which adult has emerged; e, f, adult insects — e, male;/, female, a and b, natural size; c-f, enlarged. (After Riley and Marlatt, U. S. Dept. Agr.) 130 INSECT PESTS OF FARM, GARDEN AND ORCHARD reddish or yellow. The larvae are grayish above and lighter beneath and reach a length of about a half-inch. They appear like any common small caterpillar but on examination will be found to have eleven pairs of legs in place of the eight pairs found on the caterpillars. A third species, more common than any of the others is the Grass Saw-fly, (Pachynematus extensicornis Norton), The adults of this species do not differ markedly from the others but the larvae became larger and are green or yellowish-green in color and have only ten pairs of legs in place of the eleven pairs found in the former species. Adults of all these forms appear rather early in the spring and larvse feed on the wheat, then in mid-summer go into the ground and remain there as larvse until early the next spring. They may possibly be destroyed in this situation by deep plowing, which would prevent the escape of the adults. So far, injury has not been extensive enough to call for treatment. Some Wheat-maggots Very similar to the Hessian fly in its mode of injuring the wheat-stalk is the Wheat-stem Maggot (Meromyza americana Fitch). The adult flies were first described by Dr. Fitch in 1856, though the work of the maggots had probably been noticed as early as 1821 by James Worth of Bucks County, Pa., and by the Michigan Farmer in Michigan about 1845. Extending from Dakota and Manitoba to Texas, the range of this insect practically covers all the eastern United States and southern Canada. Unlike the Hessian fly it feeds and breeds upon wild grasses and is thus much more difficult to control. Prof. A. J. Cook found the larvae in both barley and oats in Michigan, Prof. F. M. Webster reared an adult from blue grass (Poa pratensis), and Dr. Jas. Fletcher records it as breeding in Agropyrum, Deschampsis, Elymus, Poa, and Setaria viridis in Canada. Life History. — Like the Hessian fly the adult flies lay their eggs on fall wheat in September and October, and the young maggots when hatched work their way down into the stem, either cutting it off or causing it to discolor or die. The eggs are about one-fortieth of an inch long and of a glistening white color. The INSECTS INJURIOUS TO SMALL GRAINS 131 larvse are a light greenish color, about one-fourth of an inch long tapering toward the terminal end while subcylindrical posteriorly, being quite elongate. The pupae are the same color as the larva?, but more rounded, being only one-sixth of an inch long, and reveal the legs and wing-cases of the imago forming within them. The external case of the pupa, called the puparium, is merely the shrunken and hardened cast skin of the last larval stage, within which the insect transforms to the pupa. The fly is about one-fifth of an inch long. It is of a yellowish-white color with a black spot on the top of the head, three broad black stripes on the thorax, and three on the abdomen, which are often interrupted at the sutures, so that they form dis- tinct spots. The eyes are a bright green. The winter is pass- ed by the larvae in the young plants and in spring they trans- form to pupae and adult flies. These in turn deposit eggs in such a position that the maggots issuing from them may readily feed upon the succulent portions of the growing stalk. Numerous larvae thus sapping the life of the plant soon kill it outright or cause the top and head to wither and die. The adults of this brood emerge in July and lay eggs on volunteer wheat and grasses, the maggots working in the same manner as in the fall and coming to maturity so that another brood of flies lays eggs for the fall brood on the newly planted wheat. Owing to the fact that this insect breeds also in grasses dur- ing late summer it is much more difficult to combat than were it confined to wheat as its food-plant, as is the Hessian fly. Fig. 112. — Wheat bulb-worm (Meromyza ameri- cana): a, mature fly; h, larva; c, puparium; d, infested wheat-stem — all enlarged except d. (After Marlatt, U. S. Dept. Agr.) 132 INSECT PESTS OF FARM, GARDEN AND ORCHARD MMM -filiii^il^ftfe Remedies. — "If the grain is stacked or threshed and the straw stacked or burned," says Professor Webster/' it is clear that the number escaping would be greatly reduced," for, as the adults emerge soon after harvest, they would escape to deposit their eggs were the straw left in the fields, but "it is not likely that those in the centre of the stacks would be able to make their way out, and the threshing-machine would destroy many more. How much could be accomplished by late sowing of grain is uncertain, as the females are known to occur abundantly up to October. If plots of grain were sowed immediately after harvest in the vicinity of the stacks, many of the females could, no doubt, a be induced to deposit IMiiiiHiiHMMHpMpHMIPM^ eggs therein, and J^^I^J^gpJgl^ these could be destroyed by plowing under." Burning of the stubble will also aid in keeping this pest under control. There are several undetermined species of flies belonging to the genus Oscinis , which have practically the same life history as the wheat stem-maggot and injure the wheat in the same manner. They Fig. 113.— The American frit-fly (OsamsmriaftiZzs ^^^y closely resemble Loew): a, larva or maggot; 6, puparium;c, adult the common house-fly fly. (After Garman.) -^^ miniature, being about one-fourth as large. They will not need consideration by the practical farmer other than in applying methods of control as already given. One species of this genus, determined by Pro- fessor H. Garman as Oscinis variabilis Loew and christened the American Frit-fly, has been found common in Kentucky and Canada, but in the larval stage is so nearly identical in appear- ance and habit with the stem-maggot that it can with difficulty be distinguished from it. That these pests do not do more injury is probably due, to a INSECTS INJURIOUS TO SMALL GRAINS 133 considerable extent, to the fact that large numbers of them are destroyed by a small hymenopterous parasite, known as Coelinus meromyzoe Forbes, which very commonly infests the larvae, and by other parasites and predaceous insects. Rarely will these pests do serious damage, but very often it is sufficient to merit consideration, and only a knowledge of their life history can give a key to their successful control. The Wheat-midge * History. — While the Hessian fly attacks the stalk of the wheat-plant, another species of the same family, known as the Fig 114. — Wheat-midge {Diplosis tritici): a, female fly; h, male fly; c, larva from below. (After Marlatt, U. S. Dept. Agr.) _ Wheat-midge, or "Red Weevil," often does very serious damage to the maturing head. It, too, is a foreigner, having first been noticed as injurious in Suffolk, England, in 1795, though probable references to its depredations date back as early as 1741. "In ' Ellis's Modern Husbandman ' for 1745 the attacks of the vast numbers of black flies (the ichneumon parasites) are noticed in the following quaint terms: 'After this we have a melancholy sight, for, as soon as the wheat had done blooming, vast numbers of black flies attacked the wheat-ears and blowed a little yellow maggot which ate up some of the kernels in other parts of them, and which caused multitudes of ears to miss of their fulness, acting * Diplosis tritici. Family Cecidomijiidce. See Bulletin No. 5, Vol. I, 2d Ser., Ohio Agr. Exp. Sta., F. M. Webster. 134 ' INSECT PESTS^OF FARM, GARDEN AND ORCHARD in some measure like a sort of locust, till rain fell and washed them off; and though this evil has happened in other summers to the wheat in some degree, yet if the good providence of God had not hindered it they might have ruined all the crops of wheat in the nation.' (Hind's ' Essay on Insects and Diseases Injurious to Wheat Crops,' page 76)". It seems probable that it was first introduced into America near Quebec, where it " appears to have occurred" in 1819, and was first observed in the United States in northwestern Vermont in 1820. It did not become very destructive, however, until 1828, from which time until 1835 it kept increasing in such numbers as to cause the abandonment of the wheat crops in some localities throughout northern New England. Serious damage was reported as due to this pest every few years until about 1860, being most severe in 1854, in which year Dr. Fitch estimated the loss in New York alone at $15,000,000, and in 1857, and 1858. Since then no widespread injury has occurred, though local outbreaks are frequent, and it has spread south to the Gulf States and westward to Iowa, Minnesota, and Arkansas. Life History. — The adult flies are small, two-winged insects, about an eighth of an inch long, of a yellow or orange color. They appear about the middle of June and lay the eggs "in a small cavity at the summit of, and formed by a groove in, the outmost chaff covering the incipient kernel." They hatch in about a week, according to Dr. Fitch, and the maggots burrow into the forming kernels. The maggots are of a reddish color, and when an ear is badly infested give it a reddish tinge, on account of which the insect is often called the "red weevil." When full grown the larvse enter- the ground and usually form cocoons, in which they pass the winter in the pupal stage, though they often hibernate without such protection. Though doubtless there is usually but one brood in a season, observations by Professor F. M. Webster and others seem to point to the fact that there sometimes are two broods, as adults have been observed from August into November. Besides wheat, the wheat-midge also sometimes injures rye, barley, and oats. Remedies. — Plowing infested fields in the fall so deeply that the midges will be unable to reach the surface upon developing INSECTS INJURIOUS TO SMALL GRAINS 135 in the spring is by far the best means of controlHng this pest, while burning the stubble previous to plowing, and a rotation of the crop, will also be of considerable aid. The English Grain-louse * The most common plant-louse affecting wheat and other small grains is a large green species which is always to be found on wheat plants, but which occasionally increases very rapidly, and clustering on the ripening heads sucks the juices so as seriously to injure the quality and weight of the wheat. In the North the first individuals are found on young wheat in April, though during open win- ters they may be found on the plants, and in the South they continue to reproduce during most of the winter in open sea- sons. The aphids feed upon the leaves until the grain commences to head, when they assem- ble on the heads among the ripening kernels. The females give birth to live young, bearing from 40 to 50 each, which become full grown in ten days to two weeks, and then reproduce, as is the usual method of reproduction with plant-lice (see page 390), so that they multiply with great rapidity, and where so few were present as to be hardly noticeable, in a few weeks they will be swarming over the heads in myriads. As the small grains ripen they migrate to various grasses and are not much in evidence during midsummer, * Macrosiphum granaria Buckton. Family Aphididoe. A nearly related species, Macrosiphum cerealis Kaltenbach, has very similar habits, is commonly associated with the species, and has not been distinguished from it by most writers. It may be recognized by lacking the blackish markings on the abdominal segments. See Pergande, Bulletin 44, Bureau of Entomology, U. S. Dept. Agr. Fig. 115. — The German grain aphis(Macro- siphum cerealis Kalt) : a, winged migrant 6, nymph of same; c, wingless partheno- genetic female; d, same showing exit hole of parasite — enlarged. (After Riley, U. S. Dept. Agr.) 136 INSECT PESTS OF FARM, GARDEN AND ORCHARD but later migrate to volunteer oats and wheat, upon which they subsist until fall wheat is available. Owing to the cool weather of fall and the fact that but few individuals survive the attacks of their parasites during the summer, they rarely become abundant enough to do any damage to grains in the fall. So far as known, they hibernate over winter among the leaves of the growing plants, enough surviving both snow and cold to infest the crop the next spring. Whether true males and females produce eggs on the grain is unknown, for though they have been reared under artificial conditions, they have never been observed in the field. Fig. 1 16. — Grain a p h i d s clustered on wheat head, greatly enlarged. (After Weed.) Fig. 117. — ^Wheat-louse parasite (Aphidius avenaphis Fitch), and parasitized louse from which it has issued. (Copied from J. B. Smith.) Professor F. L, Washburn observed at least fourteen generations up to November 8, 1907, in southern Minnesota. As with other aphids, both winged and wingless individuals occur throughout the season. The wingless individuals are about one-tenth inch long, with black antennae as long as, or longer than the body, are of a yellowish-green color, often slightly pruinose, and long black nectaries extend from either side of the abdomen. The winged individuals are about the same length, with a wing expanse of about three-eighths inch, with antennae INSECTS INJURIOUS TO SMALL GRAINS 137 a third longer than the body, and are of the same general colora- tion except that lobes of the thorax are brown or blackish, and the abdomen is marked with four or five transverse blackish spots in front of the nectaries. Like the other aphids affecting small grains, this species is held in check by parasitic insects, aided by predaceoiis insects and fungous diseases. Injury by the aphids is usually due to the parasites having been killed off, thus giving the aphids oppor- tunity to multiply unchecked. Among the most abundant parasites are species of the genus Aphidius (iamily Braconidoe) , one of which is shown in Fig. 117, greatly enlarged. Cold, wet weather in spring greatly retards the development of these parasites, so that the aphids are always more numerous in such sea- sons. It has also been observed that an outbreak is often pre- ceded by several dry seasons, which may be due to the fact that such dry seasons check the development of fungous diseases which kill off large numbers of the aphids and which do not propagate in hot dry weather. Thus weather conditions are very intimately associated with the abundance of the pest. When the parasites become abundant they will often completely rid a field of the aphids within a few days. All of the common ladybird -beetles {Coccinellidoe), Syrphus-fly larvae, and lace-winged fly larvae {Chrysopidoe) are commonly found feeding upon the aphids. Control. — No practical remedy for this species is known nor are means of control easily suggested. The suppression of volunteer wheat and oats in early fall will prevent the multiplica- tion of the pest before fall-sown wheat is available, and the late sowing of wheat in the fall will reduce the numbers entering hibernation. A wise rotation and the thorough preparation of the seed-bed and liberal fertilization will be of value in avoid- ing injury in the same way as has been described for other pests of small grains. Fortunately this species rarely does very wide- spread injury and its parasites usually soon bring it under control. The Spring Grain-aphis or Green Bug * Though long known as a serious pest of small grains in Europe, this aphis has done widespread injury in this country only during the past ten years. Though it- occurs throughout the territory * Toxoptera graminum Rond. Family Aphididoe. 138 INSECT PESTS OF FARM, GARDEN AND ORCHARD north of latitude 41°, with the exception of the North Atlantic States, as far west as longitude 105°, the worst injury has been done in northern Texas, Oklahoma, and Kansas, though it has also been injurious in the Carolinas and Tennessee. The habits of the insect during the winter have not been suffi- ciently studied to speak authoritatively, but it seems probable that it normally passes the winter in the egg stage, the small shin- ing black eggs, one-fortieth inch long, being laid on the leaves in the late fall. In the South, however, it often continues to reproduce throughout the winter, and with a mild winter the numbers so multiply that unless checked by parasites serious injury is done by late winter or early spring. Both wingless and winged forms occur throughout the year. The wingless female Fig. 118. — The spring grain-aphis or "green bug" (Toxoptera grammum) : a, winged migrant; h, antenna of same, a, much enlarged; h, highly magnified. (From Pergande, U. S. Dept. Agr.) is from one-twenty-fifth to one-fourteenth inch long, yellowish- green, with a median line slightly darker, eyes and most of the antennae black, of the shape shown in Fig. 119. The winged female is slightly larger, with a wing expanse of about one- quarter inch, and of the same general coloration, except that the head is brownish-yellow and the lobes of the thorax are blackish. The aphids hatching from the eggs are all females, which give birth to live young, no male forms occurring during the summer. During her life of slightly over a month a female will give birth to 50 or 60 young, which commence to reproduce in the same manner INSECTS INJURIOUS TO SMALL GRAINS 139 when about seven days old, so the numbers of the pest obviously increase with enormous rapidity, and with thousands of tiny beaks pumping out the sap the young grain plants soon succumb. The rate of reproduction and growth is, of course, much slower in colder weather, the above being the average for the growing season. Thus in an open winter the aphids will continue to multiply, and by February, in northern Texas, small spots of wheat and oats will show the effect of their work, by March the injury may become widespread and serious, and by the middle of April the crops may be ruined. As the aphids become excessively abundant and the Fig. 119. — Toxoptera graminum: a, newly born, and h, adult wingless green bug, greatly enlarged. (After S. J. Hunter.) food supply disappears, almost all develop wings, and immense clouds of the winged females are carried northward by the winds, so that an outbreak in early spring in the South leads to an infestation farther north, and excessive multiplication will again carry the pest still northward, progressing in that direction as it increases during the season, rather than being spread at one time. Thus in 1907 it became abundant in Oklahoma in April, in Kansas in May, and by July it was found in Minnesota, where it rarely occurs and does no damage. With the maturing of wheat and oats 140 INSECT PESTS OF FARM, GARDEN AND ORCHARD the aphids migrate to various grasses, being particularly fond of Kentucky blue-grass, and may subsist on corn, on which they may feed until oats and wheat are available in the fall. Oats is the favorite food, and outbreaks of the pest have always been worst where volunteer oats is generally grown, the aphids increasing on it in the early fall and winter and later spreading to wheat. By October 15th in Minnesota and by early November in Kansas the true winged males and wingless egg-laying females have been observed, but strangely enough they have only been secured in small numbers by being reared in the laboratory, and have not been observed in the field, so that although these females laid eggs Fig. 120. — Lysiphlebus testaceipes Cress., adult female and antenna of male — greatly enlarged. (After Webster, U. S. Dept. Agr.) freely on the leaves of grain, we do not know whether they are essential or not to the life history of the insect in the field, for while the eggs are being produced other females continue to give birth to live young until the cold of winter, and they have been observed to reproduce with a daily mean temperature barely above freezing. Natural Control. — The natural control of this most destructive pest involves a most interesting relationship between temperature and development of the parasites which check its development. " The ' green bug ' in normal years — that is, when its breeding INSECTS INJURIOUS TO SMALL GRAINS 141 begins in spring — is effectively held in check by its natural ene- mies, and notably by a minute, black wasp-like insect, Lijsiphlehus testaceipes Cress. (Fig. 120), that deposits eggs singly in the 'green bugs, ' the grubs hatching from the eggs feeding in- ternally on the bug and destroying i t (Figs. 122-123). Other ^ . . , . Fig. 121. — Lysiphlebiis parasite m act of depositing natural enemies are eggs in the body of a grain-aphis — much enlarged, the larvae of certain (After Webster", U. S. Dept. Agr.) predaceous flies, and the larva? and adults of lady-beetles. The little wasp-like parasite first mentioned, however, is the one that keeps the ' green bug' in control in normal years, and in years when the latter is most abundant finally over-comes it, as was the case in 1907 in Kansas, North Carolina, and other States in the more northern part of the range of the pest." "Unfortunately this parasitic "wasp" — as with other beneficial insects — is active only while the temperature is above 56° F., or at least 10° above that at which the 'green bug' breeds freely; and herein is the whole secret of the irregular disastrous out- breaks of the 'green bug' in grain fields. As accounting for the outbreak in the year 1907, the 'green bug' had had a whole winter and the following late spring in which to breed and multiply unmolested, and it accomplished its principal damage, as in Texas and southern Oklahoma,before the weather was warm enough for the para- site to increase sufficiently to overcome it." Fig. 122.— Dead "green bugs," showing hole from which the matu- red parasite of Lysiph- lebus emerges. The top figure shows the lid still attached, but pushed back; the bot- tom figure shows the parasite emerging. Enlarged. (After Webster, U. S. Dept. Agr.) "As further illustrative of the import- ant bearing of weather conditions, it is found that in the case of the three important outbreaks of this insect, namely, for the years 142 INSECT PESTS OF FARM, GARDEN AND ORCHARD 1890, 1901, and 1907, the temperature for the first five months of each of these years, including the latter part of the winter and spring, was above the normal for the winter months and below the normal for the spring months; in other words, warm winters and cold, late springs." " The little parasitic wasp which is so useful in the control of this pest is native to this country, widely dis- tributed, and every year does its work with the ' green bug ' and with other aphids. It is always present in grain fields, as shown by its appearance every year, tc war on these pests when- ever the weather conditions make its breeding and multiplication pos- sible, and its rate of breeding is so rapid (there being a generation about every ten days) that with a week or two of favorable weather it gains con- trol over its host insects and destroys them. * Control. — Most important of all methods of control is the abandonment of the growing of volunteer oats and the destruction of all volunteer oats and wheat in the early fall. Uni- versal experience throughout the in- jured area shows that relatively little injury occurs where volunteer oats is not grown. Where small spots of grain have been injured by the pest in late winter, which is the way an outbreak usually begins in southern localities, the aphids on these small spots may be killed by spray- ing with 10 per cent kerosene emulsion, or whale-oil soap, 5 pounds to a barrel of water, by covering the spots with straw and burning or by plowing under the infested spots. Were this generally done before the aphids commence to multiply rapidly, it is entirely possible that widespread injury might be averted. * From F. M. Webster, Circular 93, Bureau of Entomology, U. S. Dept. Agr. Fig. 123. — Parasitized green bugs — enlarged. (From photo- graph, after S. J. Hunter.) CHAPTER IX. INSECTS INJURIOUS TO CORN The Western Com Root-worm * Throughout the corn States of the northern Mississippi Val- ley, wherever corn is grown upon the same land it is subject to serious injury by the Western Corn Root- worm, so called because it first became injurious in Missouri and Kan- sas and gradually spread eastward to Ohio, though not injurious south of the Ohio River. Though the life history of the insect has not been entirely determined, the following summarizes it as observed by Professors Q A T^r^vKoQ onrl T? IX/T ^iGi- 124.^The western corn root-worm: a, b. A. l^ the sides, with two transverse black V >>. jr Jf bands preceding the cauda, and the seg- \ {"%. jf ments behind it edged with dark. ' ' These ^^=%^i^JO^:^r^ differences between this and the root y'*^!- ■ -^iV aphis are shown in the accompanying . figures. "Aphis maidis has been re- ported at various times as a corn insect from New York to Texas, Minnesota and California. The species makes its appearance in midsummer, our earliest Fig. 132. — ^The wingless 1 , /T,,. .... T 1 r» 1 • female of the corn leaf- date (Illmois) bemg July 9, when speci- aphis— much enlarged, mens were found on young leaves of corn. (After Webster, U. S. Dept. We have no record whatever to show whence it comes or where it lives preceding this time. Having once commenced to breed on the food-plants mentioned, it con- tinues there until freezing weather overtakes it, when, with the death of its food plants, it gradually disappears, leaving neither eggs nor hibernating adults on or about these plants, and passing the winter we do not know how or where." Its occurrence on bar- ley in Texas in January may throw some light upon its wintering habits in the South. " The latest to develop in the field largely acquire wings, and as the sap supply in the plant diminishes they fly away. Wingless females, on the other hand, perish on the 158 INSECT PESTS OF FARM, GARDEN AND ORCHARD spot. Indications are thus very strong that this is a migrating species whose second food plant is thus far unknown." No experiments in the practical treatment of this pest seem to have been recorded. The Larger Com Stalk-borer * Throughout the South from Maryland to Louisiana and west- ward to Kansas more or less serious injury is done by large white, brown-spotted caterpillars which bore into the stalks. In spring the young caterpillars bore into the heart of the young plant and like other insects with similar habits (see page 146) are known as "budworms." Later the hollowing out of the stalk so weakens the plant that it is readily broken over by the wind. Consequently a loss of from 25 to 50 per cent of the crop not infre- quently results where the pest is abundant. Life History. — When the caterpillars become full grown in the fall they bur- row down into the tap-root and there pass the winter Fig. 133.— Work of the larger corn stalk- in a small cavity at or near w!!^" ^' general appearance of stalk in- ^^^ g^^f^^^^ ^f ^j ground. tested by the early generation of borers; , ° h, same cut open to show pupa and larval About the time the land is burrow. (After Howard, U. S. Dept. Agr.) ^^:^^^ prepared for corn, from March 15 to April 30, depending on the locality, the larva changes into a reddish-brown pupa, from which the moth emerges in ten days or more. The moth is brownish-yellow in color with * Diatraea zeacolella Dyar. 1025, U. S. Dept. of Agr. Family Crambidce. See Farmers' Bulletin INSECTS INJURIOUS TO CORN 159 wings expanding 1^ inches, the hind-wings being darker and bear- ing faint markings (Fig. 135) . The eggs are laid at dusk upon the under surface of the leaves of the young corn, and hatch in from seven to ten days. The eggs are flat, scale-like, and placed in rows of from two to twenty-five, slightly overlapping each other. They are 3-100 inch long, by two thirds as wide, at first a creamy-white, but gradually becoming a reddish brown. The young larva bores into the stalk, often destroying the "bud," and then at or near the ground, where it burrows upward in the pith, seldom damaging Fig. 134. — a, b, c, varieties of the larva of the larger corn stalk-borer; d, third thoracic segment; e, eighth abdominal segment; /, abdominal segment from side; g, same from above — enlarged. (After Howard, U. S. Dept. Agr.) the stalk above the third joint. As the borers grow they become quite active and frequently leave and re-enter the stalk, thus mak- ing several holes. The caterpillars become full grown in twenty to thirty days, and are about one inch long, dirty-white, thickly cov- ered with dark spots, each of which bears a short, dark bristle. The mature caterpillar bores outward to the surface of the stalk, making a hole for the escape of the adult moth, which it covers with silk, and then transforms to a pupa in its burrow. This occurs during July, and the moths of the second generation emerge in seven to ten days. The second brood larvae feed on the old stalks, tunneling them between the second joint and the ground, and become full grown about harvest time when they go into winter quarters in the root as above described. 160 INSECT PESTS OF FARM, GARDEN AND ORCHARD Control. — It has been observed that late planted corn is much less injured than that planted early, but as it is more seriously injured by some other pests, late planting may not be advisable. Where corn has been seriously injured, the old stalks or butts should be dragged off the field and burned late in the fall, thus destroying the over- wintering borers. When corn is stripped for fodder, the stalks left stand- ing and the land sown in small grain, the most favor- able conditions are allowed the borers for safely passing the winter and developing into moths which will fly to new fields in the spring. A simple rotation of crops will also lessen injury con- si derably, as Dr. L. 0. Howard has observed that Fig. 135. — The larger corn stalk-borer, a, female; b, wings of male; c, pupai — all somewhat enlarged. (After Howard, U. S. Dept. Agr.) where fields which had been in corn the previous year were dam- aged 25 per cent, those planted on sod land were damaged but 10 per cent, though reasonably close to land which had been in corn. Bill-bugs * Throughout the South and often in the more Northern States, Canada, and the West the bill-bugs sometimes become serious enemies of young corn-plants. They are called *' bill-bugs " on account of the prolongation of the head, termed a bill or snout, peculiar to all the weevils or "snout-beetles," by means of which they are enabled to drill holes in the corn-stalks. Several species belonging to the genus Sphenophorus are commonly injurious to corn. One of these, S. parvulus Gyll., also attacks small grains and timothy, and is therefore known as the Grain Sphenophorus. Another species, S. obscurus Boisd., does considerable injury to sugar-cane in Hawaii. The adult beetles are from one-fourth to * Species of Sphenophorus. Family Calandridce. See S. A. Forbes, 23d Report of the State Entomologist of Illinois. Also Farmers' Bulletin 1003, U. S. Dept. Agr., and Z. P. Metcalf, N. C. Expt. Sta. Bull, 13 Tech. INSECTS INJURIOUS TO CORN 161 three-fourths of an inch long, of the form shown in the illustration, and are of a brown or black color, marked with darker longitudinal ridges on the wing-covers. The larva is a thick fleshy white grub, from one-fourth to five-eighths of an inch long, with a brown head and cervical shield on the first segment, and footless. Life History. — The life histories of the different species are but partially known. Fig. 13G. — Sphenophorus ochreus, larva, adult, and work in roots of Scirpus. (After F. M. Webster, "Insect Life.") S. parvulus hibernates over winter as a beetle, appearing in March and April. The female punctures the stalk of wheat or timothy — oats and barley are also sometimes attacked — a little above the roots, and deposits her egg in the cavity. This is done in May or June or even up to July 1st. The larvae are to be found during July, becoming full grown and pupating during the latter part of that month. The larva) will eat out^quite a cavity in the interior of the stalk or bulb, and then attack the roots, thus often killing a whole clump or stool of small grain or timothy. The pupal stage is passed in a small cell in the earth and lasts from two to three weeks, adult beetles emerging from the middle of August to the first of October. 162 INSECT PESTS OF FARM, GARDEN AND ORCHARD One of the species most injurious to corn is S. ochreus Lee. The hfe history is much the same as that of S. parvulus, though eggs have been found as late as July 30th, The natural food-plant of this species, however, is the common club-rush (Scirpus jiuvia- tilis), the roots of which consist of bulbs connected by smaller slender roots. The eggs are deposited in or about the roots of this rush, never having been found on corn. The bulbs of the rush are very hard and oftentimes as large as hens' eggs. In them the larvae burrow, becoming full grown and transforming to pupae, from which the adult beetles appear in August and September. When the rush becomes too hard for the beetles they often attack a common reed (Phrag mites communis), piercing and splitting lengthwise the unfolded terminal leaves, and eating out the suc- culent portions within. The injury to corn is done by the beetles while the corn is still young, feeding upon it in the same manner as do the other species. " Standing with the head downward and the feet embracing the lower part of the stalk," says Dr. Forbes, "thej?- slowly sink the beak into the plant, using the jaws to make the necessary perforation. By moving forward and backward and twisting to the right and left, the beetle will often hollow out a cavity beneath the surface much larger than the superficial injury will indicate." As the lower part of the stalk becomes hardened, they leave it for the terminal portion, and when the ears commence to form they often penetrate the husk and gouge out the soft cob. Sometimes the injury thus inflicted is but slight, merely resulting in a puncturing of the leaves when they unfold, these holes being in a series across the leaf resulting from a single puncture when the leaf was folded, and looking much like the work of the corn-root webworm; but when several beetles attack a young plant, they will either kill it outright or so deform the foliage and stalk that no ear will mature. Several other species have also been known to do more or less injury to corn, viz., S. scoparius, placidus, cariosus, sculptilis, and pertinax, but so far as known their habits and injuries are much the same as of those already described. Means of Control. — The control of these pests is rather a diffi- cult task. S. ochreus, as in fact are all of the species, is most injurious on recently cleared swamp-lands, and usually disappears as fast as these lands are drained and cultivated. Planting flax, potatoes, or some crop not attacked by these insects for the first INSECTS INJURIOUS TO CORN 163 crop will largely prevent so serious injury to a subsequent corn crop. The burning over of grass- and swamp-lands infested with the beetles will also be of considerable value. The Maize Bill-bug * Throughout the Southern States and northward to Kansas there has l^een more or less serious injury by a bill-bug which has Fig. 137. — Sections of sugar-cane showing work of Sphenophorus obscurus: a, larva; b, pupa; c, probable points of oviposition. (After Riley and Howard, "Insect Life.") been recognized for many years as Sphenophorus robustus Horn. Recently Dr. F. H. Chittenden has recognized this insect as a new * Sphenophorus maidis Chittn., see E. O. G. Kelly, Bulletin 95, Part II, Bureau of Entomology, U. S. Dept. Agr See also W. P. Hayes, Tech. Bulletin 6, Kansas Expt. Station, and Farmers' Bulletin 1003, U. S. Dept. Agr. 164 INSECT PESTS OF FARM, GARDEN AND ORCHARD species and Mr. E. O. G. Kelly has published a complete account of its life history, from which the following is taken. As will be seen below this species is known to pass its entire life history upon the corn-plant so that the common name given it appropriately distinguishes it from other bill-bugs previously mentioned. It has, however, been found feeding and probably breeding in swamp-grass (Tripsacum dactyloides) , which may be its native food plant. Life History. — The eggs were found in southern Kansas during June, laid in punctures made by the female in young corn-plants. These egg punctures are mere slits and do not seem materially to injure the plant. The eggs hatch in from seven to twelve days, and from them emerge small footless, dingy white grubs, with chestnut-brown heads, of the appearance shown in Fig. 140. "They at once begin feeding on the tissues of the young corn at the bot- ^'(S^wlt riS Chittn"! t°» "f the egg puncture, directing — four times natural size. (Af- their burrow inward and downward ter Kelly, U. S. Dept. Agr.) ^^^^ ^^le taproot. When they finish eating the tender parts of the taproot they direct their feeding upward, continuing until full grown, allowing the lower portion of the burrow to catch the frass and excrement. This burrowing of the taproot of the young growing corn-plant is disastrous to the root system; . . . allowing it to die or become more or less dwarfed." Often the young larvae bm-row into the heart of the plant and cut off the growing bud, thus killing the top. The larvae become full grown early in August, when they are about four-fifths of an inch long. '' The larvae, on finishing their growth, descend to the lower part of the burrow, to the crown of the tap- root, cutting the pith of the cornstalk into fine shreds, with which they construct a cell where they inclose themselves for pupation." The pupae are to be found in these cells in late August and early September, the pupal stage lasting ten to twelve days. The adults INSECTS INJURIOUS TO CORN 165 commence to emerge by the middle of August and continue to do so until the middle of September. " Some of them leave the pupal cells, but most of them remain there for hibernation." Those which emerged disappeared and probably hibernated in some dense, coarse grass nearby. Those which hibernated in the pupal cells <^/ Adult Egg ,X'<\ v<^ Larva Pupa 19/4 vo. Oi 4) <^f Fig. 139. — Diagram representing the seasonal appearance of the maize bill- bug in 1914 in Kansas. (After W. P. Hayes, Technical Bulletin 6, Kansas Agr. Expt. Station.) emerged the next spring about the time that young corn was sprouting. The beetles are from two-fifths to three-fifths of an inch long, of a dull shining black color, and sculptured as shown in Fig. 138. " The beetles are rarely observed on account of their quiet habits and because they are covered with mud — a condition which is more or less common among several species of this genus 166 INSECT PESTS OF FARM, GARDEN AND ORCHARD and which is caused by a waxy exudation of the elytra to which the soil adheres. The presence of the adults of this species in a cornfield is made evident by the withering of the top leaves of very young corn-plants, the plants having been severely gouged. After the plants grow 10 Fig. 140.-Larva of the maize bill- to 15 inches tall they do not kill bug — twice natural size. (After them, but gouge out such large cav- Kelly, U. S. Dept. Agr.) -^j^g -^ ^^^ ^^^^^^ ^^^^ ^^^^ become twisted into all sorts of shapes. The attacked plants sucker pro- fusely, affording the young, ten- der growth for the beetles to feed upon, even for many days after the non-infested plants have be- come hard." Injury seems to be most serious on low land. Injury by this species somewhat resembles that done by the larger cornstalk-borer (Diatraea zeaco- lella), but is easily distinguished from the work of the other bill- bugs, as the punctures of the lat- ter, which usually form a row or rows of holes in the leaves when they unfold, are not always fatal to the plants. Control. — Inasmuch as most of the beetles hibernate in the corn stubble, they may be readily destroyed by pulling out and burning the stubble. Care must be taken, however, to pull out the taproot, as the stalk will be liable to break above the beetle and leave it in the ground. As the infested stalks have a poor root system, they are easily pulled. Crop rotation and fall plowing are also of great value Fig. 141. — ^Corn plant showing the result of attack of the maize bill- bug: a, larval burrow containing pupa in natural position — reduced two-thirds; 5, egg-puncture con- taining egg— enlarged (After Kelly, U. S. Dept. Agr.) INSECTS INJURIOUS TO CORN 167 The Lesser Com Stalk-borer * This small moth has been sporadically injurious for many years and seems to be on the increase in the Southern States where it is at times injurious to corn, sorghums, wheat, cowpeas and crabgrass, as well as other plants in con- siderable numbers. Description. — The moth is a small, Fig. 142. — The lesser com stalk borer: larva, greatly brownish gray form "^^^^^"^- ^^^^^ ^^^^^^^^ ^""^ ^^«^^' ^' ^O with a wing expanse of less than one inch. The fore wings of the female are darker than those of the male. The larvae are slender caterpillars, three quarters of an inch in length. Their prevaihng color is a light green with darker markings, prominent among which are brownish transverse bands. Fig. 143. — The lesser corn stalk-borer: a, male moth; b, fore-wing of female moth. Greatly enlarged. (After Luginbill and Ainslie, L. C.) Life history. — Eggs are produced throughout the summer and fall and the winter is passed in the larval or pupal stage. There are probably as many as four generations in the southern range of the insect and fewer in the North. * Elasmopalpus lignosellus Zeller. Family Pyalididt^. See U. S. Dept. Agr. Bulletin 539, Luginbill and Ainslie. 168 INSECT PESTS OF FARM, GARDEN AND ORCHARD Injury. — Injury from these insects is, as the name indicates, due to their boring in the stalks of the food plant. It may be anywhere from slight to total. They seem to prefer crops grown on sandy soil. Control. — Absolutely clean cultivation, including cleaning up of fence rows and waste places, along with late fall plowing, are recommended as the best methods of control. Fig. 144. — Map showing present known distribution of the lesser corn stalk- borer (Elasmopalpus lignosellus) in the United States. (After Luginbill and Ainslie, L. C.) The Com Ear-worm * Practically the only insect injuring the ears of field-corn and the worst insect pest of sugar-corn, is the ear-worm. In the extreme South it is almost impossible to grow sugar-corn success- fully on account of its injury, while farther north it largely reduces the profits of corn grown for the cannery, and destroys a consider- able percentage of the kernels of field-corn. It is a most cosmopol- itan insect, being found throughout the United States and in many parts of the world, and has a long list of food plants, being known as the tomato fruit-worm, tobacco bud-worm, and cotton boll- * Chloridea obsoleia Fab. Family Noctuidce. See H. Garman, Bulletin 187, Kentucky Agr. Expt. Station and Farmers' Bulletin 872, U. S. Dept. Agr.) INSECTS INJURIOUS TO CORN 169 worm when attacking these plants, besides which it feeds on beans, peas, and many garden crops and forage plants, such as cowpeas and alfalfa. Life History. — Along the Gulf Coast the first moths appear in April, in the latitude of 33° about the middle of May, and in the latitude of Delaware and Kansas, early in June. The moth is about three-quarters of an inch long with a wing expanse of about 1| inches and is extremely variable in color and markings. Some are dull olive green while others are yellowish Fig. 145. — Corn ear-worms at work. The central cob has been attacked by a nearly full-grown worm, which has bored through the husk near the middle. or nearly white and with almost no markings. In the most typical moths the wings are bordered with dark bands, the wing veins are black and the fore-wings are spotted with black. The eggs are hemispherical in shape, about one-fifteenth inch in diameter, light yellowish, and prettily corrugated with ridges as shown in Fig. 201. Those of the first brood are laid on corn, peas, 170 INSECT PESTS OF FARM, GARDEN AND ORCHARD beans, or whatever food-plants are available, and hatch in three to five days, depending upon the temperature. The caterpillars of the first generation often attack corn when about knee-high, feeding in the axils of the tender leaves, so that when the leaves unroll they bear horizontal rows of holes. The caterpil- lars are exceedingly vari- able in color, being from a light green through rose color and brown to almost black, and either striped, spotted or per- fectly plain. They be- come full grown in about 2| weeks and are then about li to 1| inches long. When done feed- ing the caterpillar bur- rows 2 to 5 inches into the soil near the base of the plant. A cell is then constructed which runs back to within a half inch of the surface of the soil, so that the moth may readily push off this surface soil and escape. The burrow finished, the larva retires to the bottom of the cell and there molts and enters the pupal. The pupa is four-fifths inch long, shining reddish-brown. During the summer the moths emerge about two weeks later, but the last generation in the fall passes the winter in the pupal stage. Thus the complete life cycle from egg to adult moth requires slightly over a month in midsummer, and from six to eight weeks for the spring and fall broods. The second generation of moths appears about the middle of July in the latitude of Delaware and Kansas. In the far South the second generation of moths appears when corn is com- FiG. 146. — Corn ear-worm or cotton boll- worm (Chloridea obsoleta): a, adult moth; h, dark full-grown larva; c, light-colored full-grown larva; d, pupa — natural size. (After Howard, U. S. Dept. Agr.) INSECTS INJURIOUS TO CORN 171 ing into silk and tassel, upon which the moths always prefer to lay their eggs. As a result, the caterpillars of the second genera- tion of the South, and the third farther North, do serious injury to field-corn, gnawing out the kernels at the tips of the ears, and furnishing favorable conditions for molds to propagate, which Fig. 147. — Corn ear-worm. Husk of ear of sugar-corn torn open, showing worms at work on tip and hole through which a full grown worm has left. do further injury. From 2 to 5 per cent of the corn crop of the country, with a cash value of $60,000,000 to $150,000,000, is thus destroyed by the ear-worm annually. The third generation of moths appears the last of August in Delaware and Kansas and gives rise to the third brood of 172 INSECT PESTS OF FARM, GARDEN AND ORCHARD caterpillars, which is there the most destructive brood on field- corn and sugar-corn, frequently causing a loss of from 10 to 50 Fig. 148. — Tip of ear of corn showing eggs of corn ear-worm on silks. (After Quaintance and Brues, U. S. Dept. Agr.) per cent of the latter crop. The caterpillars become full grown during the latter part of September and change to pupae, which hibernate over winter as already described. INSECTS INJURIOUS TO CORN 173 In the Gulf States there are four full broods and along the Gulf Coast there may be five or six, while in the Northern States there are but two generations, with possibly but one in Ontario. Control. — As the pupa pass the winter in the soil, by all means the most satisfactory and practical means of control is to plow infested land in late fall or during the winter, plowing deeply and harrowing. This will break up the pupal cells, crush some of the pupaj, and expose others to the rigors of winter to which most of them will succumb. The early planting of field-corn prevents the moths from lay- ing their eggs upon it, as it will have passed the silking stage and other fields which are in silk will be preferred; it being possible thus to reduce the injury by at least a third by early planting. Silks and foliage of sweet corn are sometimes poisoned with arsenate of lead applied in the form of a dust, three to five appli- cations being used, and much benefit has been recorded from the treatment but it has not yet proven practical for field corn on account of the expense. The European Com Borer * Concerning this insect, a recent importation from Europe, we can do no better than to quote from Mr. Caffrey who, in his introduction to Farmers' bulletin 1046 of the U. S. Department of Agriculture, summarizes the situation as follows: " The European Corn Borer probably is the most injurious plant pest that has yet been introduced into this country. It is now known to be present in an area of about 320 square miles near Boston, Mass. Unless repressed and restricted it may spread throughout the country and cause serious and widespread losses to the corn crop. The larvae, or borers, tunnel through all parts of the corn plant and destroy or severety injure the ears and stalks. The pest also attacks celery, Swiss chard, beans, beets, spinach, oats, po- tatoes, tomatoes, turnips, dahlias, chrysanthemums, gladiolus, geraniums, timothy, and certain weeds and grasses. * Pyrausta nubialis Hiiebner. Family Pyralididcp. See Vinal and Caffrev, Bulletin 189, Massachusetts Expt. Station and Farmers' Bulletin 1046, U. S. Dept. of Agr. The N BORER is the caterpillar ofa small moth. The mbths lay their eg'g's in flat masses^,^ on. the undersides yNi/;A of the-corn leavej'. ' /:W/ The caterpillars^^H?^ hatch from these egg5 and feed at fir3t on. the leaves, tut soon bore into the tassels.the stalk, the leaf-ribs and theear^ They live in th e j^talkb all winter and | "^ in spring change | to reddish-brown pupae^ which 5oon transform. '' again to moths.. The pest also attacks other_^arden plant.s,weeds, and larger grasses,and lives through the winter in the. jtalks of these plants as yyeii as in corn. . Burn All Plants Containing Caterpillar5. Cornstalks, corn stubble, g'rasses, weeds, and |f|j 5talks of garden plants should be thus destroyed J A| throughout infested areas during" fall, 'IL'W^ llllu winter or early spring^.No other effective method is known for cornbating" this pest. 3roken tassels with i extrusrons of saw dust like material at the breaks are the plainest signs of an infested field Holes in the stalk w thsawduit I ke debris extruded uidicate where the borer IS at work Fig. 149. — Department of Agriculture warning against the European corn borer. (After Caffrey, Farmers' Bulletin 1046.) — 174 INSECTS INJURIOUS TO CORN 175 There are two generations each year, so that multiplication and spread are rapid, especially as very few of the borers are destroyed by natural enemies. The winter is passed in the larva or borer stage within infested plants. To suppress this pest burn or otherwise destroy during the fall, winter, or spring all cornstalks, corn stubble, crop remnants, and stalks of garden plants, weeds, or wild grasses within the infested areas Hkely to harbor the overwintering borers. Work of this kind is now being conducted by the Federal, State, and local authorities, and the hearty cooperation of all property owners, tenants, or other interested persons is earnestly solicited. This work must he done very thoroughly. The borers in a few over- looked plants may increase by the end of the season to as many as were present before the clean-up. To prevent the spread of the insect, quarantine measures, both Federal and State, must be strictly enforced to prevent shipment of infested plants or plant products out of the area now infested. Since the date of this bulletin (April, 1919) the borer has been found in New York State, an area of 400 square miles near Schen- ectady having been found to be infested. Since little work has been done on the insect in this country except through the U. S. Bureau of Entomology we give here also a copy of the posters summarizing the apperance of the injury, just as they were sent out by the bureau. It is impossible to predict how rapidly the insect will spread or how well it will adapt itself to our conditions. It can be said, however, that it is poten- tially the most serious pest which has ever threatened the corn of the country. CHAPTER X INSECTS INJURIOUS TO STORED GRAINS * The farmer who stores his grain, awaiting a higher price, is sometimes sadly disappointed to find that it has been so riddled by "weevil " that it brings no more than had it been sold previously. The term "weevil" is rather a comprehensive one, being commonly applied to almost every insect infesting stored food- products. Only a few species are commonly injurious in the farm granary. Grain-weevils Of these the Granary-weevilf and the Rice-weevil { (Fig. 150), are the most common and widely distributed. Both of these 'insects have in- fested grain from the most ancient times, so long, in fact, that the granary-weevil has lost the use of its wings and remains entirely in- doors. They are small, brown beetles, from one-eighth to one-sixth of an inch in length, with long snouts which are of great service in boring into the kernels of grain. By means of them the females punc- ture the grain and then insert an egg in the cavity. The larva * See Farmers' Bulletin 1029, U. S. Dept. Agr., and G. A. Dean, BuUetin 189, Kansas Agr. Exp. Station, t Calandra granaria Linn, j Calandra oryzce Linn. Family Calandridce. 176 Fig. 150. — The grain weevil {Calandra granaria) : a, beetle; h, larva; c, pupa; d, the rice weevil (C. oryza: beetle — all enlarged. (After Chit- tenden; U. S. Dept. Agr.) INSECTS INJURIOUS TO STORED GRAINS 177 hatching from this is without legs, somewhat shorter than the adult, white in color, and of a very robust build, being almost as broad as long. It soon devours the soft interior of the kernel and then changes to a pupa, from which the adult beetle emerges in about six weeks from the time the egg was laid. Only a single larva inhabits a kernel of wheat, but several will often be found in that of corn. Not only do the larvae injure the grain, but the beetles feed upon it, and then hollow out a shelter for themselves within the hull. The beetles are quite long-lived, and thus do considerable damage. The egg-laying period is equally long, and as there are three or four broods in the North and six or more in the South, it has been estimated that the prog- eny of one pair would amount to 6000 insects in a single season. Grain-beetles Another beetle very common in the granary, but of quite different appearance, is the Saw-toothed Grain-beetle* (Fig. 151). Fig. 151. — ^The saw-toothed grain beetle (Silvanus surinamensis) : a, adult beetle; h, pupa; c, larva— all enlarged; d, antenna of larva — still more enlarged; d, the red or square-necked grain beetle (Cathartus gemellatus Duv.) (After Chittenden, U. S. Dept. Agr.) It is a cosmopoUtan pest and is also nearly omnivorous. The beetle is only about one-tenth of an inch long, very much flattened, of a dark-brown color, and may be easily recognized by the six saw- like teeth on each side of the thorax. The larva is of a dirty- white color, and quite dissunilar to that of the granary weevil. * Silvanus surinamensis Linn. Family Cucujidce. 178 INSECT PESTS OF FARM, GARDEN AND ORCHARD Having six legs to carry it about, it is not satisfied with a single seed, but runs about here and there, nibbling at several. When full grown the larva glues together several grains or fragments into a little case, and inside of this transforms to the pupa and then to the beetle. In early spring this life cycle requires from six to ten weeks, but in summer it is reduced to about twenty-five days. Thus there are Fig. 152. — The Cadelle (Tenehroides mauritanicus) : a, adult beetle with greatly enlarged antenna above; b, pupa; c, larva — all enlarged. (After Chittenden, U. S. Dept. Agr.) from three to six or more generations during a season, according to the latitude. The Red or Square-necked Grain-beetle* is about the same size as the last species, but is of a reddish-brown color, and the thorax is almost square, nearly as broad as the abdomen, and not notched on the sides. Tt breeds in corn in the field and in the granary, first destroying the germ, so that it is especially * Cathartus gemellatus Duv. Family Tenebrionidce. INSECTS INJURIOUS TO STORED GRAINS 179 injurious to seed-corn. It feeds mostly out of doors, though sometimes infesting the granary. The Foreign Grain-beetle* is of much the same general ap- pearance, but smaller and of a more robust appearance. It feeds upon a great variety of stored products as well as grain, but rarely becomes troublesome. The Cadellef also has the bad habit of first attacking the embryo or germ of the kernel, and going from one kernel to another, thus destroys a large number for seed purposes. It possesses, however, the good trait of feeding on other injurious grain- insects. The beetle is oblong, flat, nearly black, and about one-third of an inch long. The larva is of a whitish color, with a brown head, the thoracic segments are marked with brown, and Fig. 153. — The Mediterranean flour-moth (Ephestia kuehniella): a, moth; 6, same from side, resting; c, larva; d, pupa — enlarged; e, abdominal joint of larva— more enlarged; /, larva, dorsal view. (After Chittenden, U. S. Dept. Agr.) the abdomen terminates in two dark horny processes. It is a fleshy grub, nearly three-fourths of an inch long when full grown. Flour- and Meal-moths The larvae of several small moths sometimes infest grain in store, but rarely do it serious damage, preferring the softer flour, meal and food-products. The most destructive of these is the Mediterranean Flour moth| (Fig. 153). This insect was practically unknown until * Cathartus advena Waltl. t Tenebroides mauritanicus Linn. Family Trogositidoe. X Ephestia kuehmella Zell. Family Pyralididcp. See W. G. Johnson, Ap- pendix 19th Report State Entomologist of Illinois, and F. L. Washburn, Special Report of the State Entomologist of Minnesota on the Mediter- ranean flour-moth. 180 INSECT PESTS OF FARM, GARDEN AND ORCHARD 1877, but during recent years it has occasioned the loss of many thousands of dollars to mill-owners. It occurs throughout Europe, and is found in Mexico and Chili. It was first recognized in America in 1889, and has since done an increasing amount of damage in California, in New York and Pennsylvania, North Carohna, Alabama, New Mexico, and Colorado, and has become quite generally distributed. " The caterpillars form cylindrical silken tubes in which they feed, and it is in great part their habit of web-spinning that renders them so injurious where they obtain a foothold. Upon attaining full growth the caterpillar leaves its original silken domicile and forms a new web, which becomes Fig. 154. — The Indian meal-moth (Plodia interpunctella) : a, moth; b, pupa; c, caterpillar; /, same — dorsal view, somewhat enlarged; d, head, and e, first abdominal segment of caterpillar — more enlarged. (After Chit- tenden, U. S. Dept. Agr.) a cocoon in which to undergo its transformations to pupa and imago. It is while searching for a suitable place for transforma- tion that the insect is most troublesome. The infested flour becomes felted together and lumpy, the machinery becomes clogged, necessitating frequent and prolonged stoppage, and result- ing in a short time in the loss of thousands of dollars in large establishments." The life cycle of this insect requires ordinarily about two months, but may be completed in thirty-eight days under the most favorable conditions. The adult moth measures a little less than an inch across the expanded wings. The fore-wings are of a lead- gray color, with transverse black markings, while the hind- wings are dirty whitish, with a darker border. The Indian Meal-moth* (Fig. 154) larvae resemble those of the grain-beetles in having a special liking for the embryo of * Plodia interpunctella Hbn. Family Pyralididoe. INSECTS INJURIOUS TO STORED GRAINS 181 wheat-grains. They spin a fine silken web as they go from seed to seed, to which they become attached, and to which is added a large amount of excrement, thus spoiling for food much more grain than is actually injured. The moth has a wing-expanse of an inch; the inner third of the fore-wings being a whitish-gray, and the outer portion reddish-brown, with a coppery lustre. The Meal Snout-moth* (Fig. 155) is of a light brown color, Fig. 155. — ^The meal snout-moth (PyraKs /arinaKs) : a, adult moth ; 6, larva; c, pupa in cocoon — twice natural size. (After Chittenden, U. S. Dept. Agr.) the thorax, base, and tips of the fore-wings being darker brown. The wings expand nearly an inch and are otherwise marked with whitish lines as shown in the figure. It is very similar to the last-mentioned species in its habits, constructing long tubes with silk and particles of the food in which it is living. The life- history is completed in about eight weeks, and four generations may occur in a year. The moisture of "heated" grain is most favorable for the development of this pest, and it need not be feared if grain is kept in a clean, dry place. The Pink corn-wormf has recently assumed importance in the southern states as an enemy of stored corn. It is a moth similar in shape to the Anguomois grain-moth, but smaller and different in color. Its wing expanse is less than one-half inch and its color is chestnut-brown with whitish-yellow markings. There are long fringes on the margins of both pairs of wings. The eggs are first laid on corn in the field, usually following injmy from the earworm or other insect. Later generations attack corn in the crib. The larvae are small pinkish caterpillars. They feed on grain and even on husks and cobs and spin webs wherever they go. * Pyralis farinalis Linn. Family Pyralididce. t Batrachedra rileyi Wals. Family Elachistidce. 182 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Angoumois Grain-moth * By far the worst granary pest throughout the South is the " fly-weevil," or Angoumois grain-moth. History. — This insect is an importation from Europe and receives its name from the fact that in 1760 it " was found to swarm in all the wheat-fields and granaries of Angoumois and of the neighbor- ing provinces [of France], the afflicted inhabitants being thereby deprived of their principal staple, and threatened with famine and pestilence from want of wholesome bread." The insect was first noted in this country in North Carolina in 1730, and in 1796 was so abundant as to extinguish a lighted candle when a granary was entered at night. It is essentially a southern insect, being very injuri- ous to stored corn in the Gulf States. Of late years it seems to be mov- ing steadily north- ward, being re- ported as injurious in central Pennsyl- vania and Ohio. Wheat, corn, oats, rye, barley, sor- FiG. 156. — The Angoumois grain-moth (Sitotroga cereal- ghum-s e e d, and ella): a, eggs; b, larva at work; c, larva, side view; d, pupa; €, moth; /, same, side view. (After Chitten- even cow-peas are den, U. S. Dept. Agr.) subject to injury. Life History. — The injury is not done by the moth, as might be reasonably supposed from the fact that it is the only form of the insect usuafly seen, but is done by the small caterpillars which feed within the grain, where they may be found during the winter. The caterpiflar eats to the surface of the kernel, but not through it, thus leaving a thin lid which the moth can easily push aside when it comes out in the spring, and then covers itself with a fine silken web. At this time the caterpfllar is usuafly fully grown and is about one-fifth of an inch long, of a white color, with the head yeflowish and harder, and having six jointed * Sitrotoga cerealella Oliv. Family Gelechiidoe. See J. L. King, Circular No. 1, Pennsylvania Dept. Agr. INSECTS INJURIOUS TO STORED GRAINS 183 .A V^-- legs in front, a series of four pairs of fieshy pro-legs along the middle, and another pair of soft legs at the end of the body. With warm spring weather the caterpillar changes to a pupa, and about the time that the wheat comes into head the adult moth emerges. As soon as it emerges, whether outdoors or in a barn, the moth at once flies to the grain-field, where the eggs are deposited. The exact time at which the moths emerge varies, but occurs some time late in May or in June. The moths quite closely resemble the clothes-moth often found flying about houses. The wings are quite narrow, and when expanded measure about one-half an inch from tip to tip, being of a yellowish or buff color, marked Avith black. The eggs are laid in the longitudinal channel on the side of the grain. Each female lays from sixty to ninety eggs in lots of about twenty each, one lot thus being about enough to in- fest the kernels of a head. The eggs hatch in from four to seven days. The young cat- erpillars are at first very active and soon find tender places and bore into the kernels, leaving almost invisible openings. These caterpillars become full grown in about three weeks, just about the time the grain is mature. About harvest-time the second brood of moths appears. These lay their eggs during July, depositing them on the ripe heads if the harvest be a little de- layed, but on the wheat in stack if harvest is prompt. Usually the caterpillars hatch- ing from these eggs become full grown and remain in the grain over winter, but in warm seasons, especially if warm in Sept- ember or when the pest is unusually abun- dant, a third brood of moths appears early in September. These lay another «Ji ■'""""-^■i" % Fig. 157. — Ear of pop- corn, showing work of Angoumois grain- moth. (After Riley.) 184 INSECT PESTS OF FARM, GARDEN AND ORCHARD batch of eggs about the middle of September, depositing them up- on the open ends of grain in stack or mow, which thus becomes more infested than that in the centre. In grain stacked outside, the caterpillars of this brood become full grown slowly and remain in the grain over winter, but if in the barn they grow faster and a fourth brood of moths appears about the middle of October, the moths being noticed in threshing. The insects continue to breed within doors all winter as long as any grain remains, though they become sluggish and cease feeding during cold weather. The number of broods is entirely dependent upon the latitude and weather conditions; in the South, where they can breed continu- ously, there being as many as eight in a year. Corn is frequently attacked, but not until it is ripe and husked, and then but rarely when husked in October and November and stored outdoors in slatted cribs. Seed-corn stored in barns, and in the South in almost any situation, is often badly injured. Aside from the loss in weight, grain when badly infested becomes unfit for milling purposes, and will even be refused by cattle and horses, which should not be urged to eat it, though hogs and fowls will readily consume it. Remedies. — Dr. J. B. Smith, in an interesting bulletin upon this pest, to which we are indebted for much of the above, advises as follows: "Thresh as soon after harvest as possible, and bulk in tight bins or in good sacks. [By "tight bins" are meant those which will not permit the entrance or exit of the moths.] If the grain is dry when harvested, it may be threshed at once; if not, as soon as it is in good condition. If the sacked grain is infested, there will not be wormy kernels sufficient to heat the grain. The moths cannot make their way out and are stifled. Nothing can come in from outside and the grain remains safe. The threshing itself kills many of the insects and jars and rubs off many of the eggs. If binned, the bins should be tight and the grain should be tested occasionally for any appreciable heating. If it heats per- ceptibly, it indicates considerable infestation, and it should be treated with carbon bisulfide at once, used at the rate of one drachm per cubic foot, or 1 pound for 250 cubic feet bin-space." Recent investigations have shown that more bisulfide will often be necessary. Those having wheat unthreshed, whether in stack or mow, should thresh at once, and treat as above directed, except that if INSECTS INJURIOUS TO STORED GRAINS 185 much of it is noticed to be wormy, it should be treated with carbon bisulfide at once, as soon as threshed, which if done thoroughly will prevent any further infestation that year. Barns and storehouses should be cleaned up and freed from all loose and scattered grain — chickens will help in this — before April 1st, so that no moths will be allowed to develop and infest the grain in the field. Places where grain has been in stock the pre- vious season should be cleaned up by the aid of chickens. Thus if there is any probability of grain being infested, it should be kept tightly covered in the spring so as not to permit the spread of the moths to the fields. Prevention of " Weevil " Undoubtedly grain-insects can usually be more successfully combated by a proper housing of the grain. No matter how often the insects are destroyed in a granary, if the remainder of the barn is full of dust, sweepings, and refuse, as it generally is, on which the beetles can feed and in which they will breed, and if the gran- ary is not absolutely tight, as soon as the gas passes off the insects from the barn will again enter the granary, and soon it will be as badly infested as ever. Cleanliness. — " Cleanliness will accomplish much toward the prevention of injury from these pests, the cause of a great propor- tion of injuries in granaries, mills, elevators, and other structures where grain and feed are stored being directly traceable to a dis- regard of neatness. Dust, dirt, rubbish, and refuse material con- taining sweepings of grain, flour, and meal are too frequently per- mitted to accumulate and serve as breeding-places for a multitude of injurious insects. " The floors or corners and walls of the barn or storehouse should be frequently swept, and all material that has no commer- cial value burned." The Granary. — "The ideal farmer's granary, from the stand- point of insect ravages, should be built at some distance from other buildings, and the rooms constructed of matched floorings so as to be as near vermin-proof as possible. The doors should fit tightly, closing upon a rabbet, which may be covered with felt or packing, and the windows covered with frames of wire gauze to pre- vent the passage of insects. The floor, walls, and ceilings should be smooth, so as not to afford any lurking-places for the insects, 186 INSECT PESTS OF FARM, GARDEN AND ORCHARD and it would be well to have them oiled, painted, or whitewashed for further security. A coating of coal tar has been strongly recommended for the latter purpose." " The value of a cool place as a repository of grain has been known of old, and a building in which any artificial heat is em- ployed is undesirable for grain storage. The ' heating ' and fer- mentation of grain, as is well known, is productive of ' weevil, ' and this should be prevented by avoiding moisture and by ventilation. The storage of grain in large bulk is to be commended, as the surface layers only are exposed to infestation. This practice is particularly valuable against the moths, which do not penetrate far beneath the surface. Frequent agitation of the grain is also destructive to the moths, as they are unable to extricate them- selves from a large mass, and perish in the attempt. The true granary-weevils (small dark-brown beetles with long curved snouts, similar to the pea- weevil), however, penetrate more deeply, and although bulking is of value against them, it is not advisable to stir the grain, as it merely distributes them more thoroughly through the mass." — Chittenden Recent observations and experiments* have shown that in the southern states, at least, injury to corn from the forms of weevil which infest the ears in the field, as well as some corn ear worm injury, may be largely prevented by planting varieties of corn which produce ears covered with husks which extend beyond the tip of the ears and form a close sheath for the ear, leaving no opening for the entrance of the weevil. Since there is more hkeli- hood of infestation from several species of weevils on corn in the field in the South, the use of such varieties would seem to be good practice for that region. Destruction of " Weevil " '\Carhon Bisulfide. — " The simplest, most effective, and most inexpensive remedy for all insects that affect stored grain and other stored products is the bisulfide of carbon, a colorless liquid, with a strong disagreeable odor, which, however, soon passes away." At ordinary temperatures it vaporizes rapidly, forming a heavy gas, which is highly inflammable and a powerful poison. * E. A. Back, Farmers' Bufletin 1029, U. S. Dept. of Agr, t See W. E. Hinds, Farmers' Bulletin 799, U. S. Dept. Agr. INSECTS INJURIOUS TO STORED GRAINS 187 Application. — It may be applied directly to the infested grain or seed without injury to its edibleness or viability by spraying with an ordinary watering-can having a fine rose nozzle. In moderately tight bins it is more effective, however, as it evaporates more slowly and diffuses more evenly, if placed in shallow dishes or pans, or on bits of cloth or cotton waste distributed about on the surface of the grain or infested material. The liquid volatil- ' izes rapidly, and, being heavier than air, descends and permeates the mass of grain, killing all insects and other vermin present. The bin should then be covered with boards, canvas, or blankets, and allowed to remain at least twenty-four hours. If to be used for seed, it should not be left for over thirty-six hours ; but if not, leave it forty-eight hours, which will do it no injury for food After treating keep the grain covered to prevent reinfestation. Amount to Use. — It was formerly recommended that the bisul- fide be applied at the rate of 1 to 3 pounds to 100 bushels of grain or 1000 cubic feet of open space. Recent experiments, however, have shown the total inadequacy of this dosage. Experiments made by Hinds and Hunter* show that the effectiveness of the gas is in direct proportion to the temperature. Below 60° F. the fumigation is ineffective and inadvisable. A dosage which will kill practically all the weevil at 67° to 70° will kill but 60 to 70 per cent at 60° to 65°. They recommend the use of 5 pounds per 1000 cubic feet where the room or bin is quite tight and the tem- perature is 70° or above. For open rooms and lower tempera- tures, the dosage must be largely increased and may not be profit- able. The above estimates are based upon the grain being in a cubical shape; if it is spread out shallow, more bisulfide will be necessary. Caution. — " Certain precautions should always be observed. The vapor of carbon bisulfide is deadly to all forms of animal life if inhaled in sufficient quantity, but there is no danger in inhaling a small amount. The vapor is highly inflammable, but with proper care that no fire of any kind, as, for example, a lighted cigar, lantern, or light of any kind, be brought into the vicinity until the fumes have entirely passed away, no trouble will be experienced." Hydrocyanic Acid Gas. — Mills and storehouses which needed * Hinds and Hunter, Journal of Economic Entomologv, Vol. Ill, p. 47: R. I. Smith, Bulletin 203, N. C. Agr. Exp. Sta. 188 INSECT PESTS OF FARM, GARDEN AND ORCHARD treatment were formerly fumigated with carbon bisulfide, which is still employed to a considerable extent, but this has been largely replaced by fumigation with hydrocyanic acid gas, which obviates the risk from fire. Directions for the use of this gas should be obtained from the entomologist of the State Experiment Station or from the Bureau of Entomology of the U. S. Depart- ment of Agriculture. Sulfur Fumes. — Professor R. I. Smith (1. c.) has made experi- ments with sulfur dioxid, produced by burning sulfur slightly wet with alcohol, and finds that it will effectively kill grain insects but injures the germinating power of the grain. " It was found that the fumes produced by burning 2^ pounds of sulfur either in a moist or dry atmosphere of 1000 cubic feet space, for twenty hours, would kill all exposed adult insects and practically all the young stages in the grain, but that this also destroyed its germinat- ing power. . . While this treatment cannot be recommended for general fumigation, there is no doubt of its being the easiest and cheapest method of fumigating corn cribs, granaries and similar places whenever they are being cleaned out and freed of insects in preparation for the reception of more grain." Heat. — The heating of grain was one of the earliest means known of combating grain insects, but has been little used in this country. Recently, however. Prof. Geo. A. Dean of the Kansas Agricultural Experiment Station,* has shown that by super- heating mills they may be rid of insect pests much more quickly and cheaply than by fumigation, and with no risk from fire, or from cyanide poisoning. His experiments show that if the temperature surrounding an insect be maintained above 120° F., with a normal amount of moisture, that in a very few minutes it will be killed. This has become one of the most popular methods of cleaning mills and may be used for small quantities of grain where there are facilities for heating it or placing it in a super- heated room, but probably carbon bisulfide fumigation will be found more practicable for small amounts. * Geo. A. Dean, Journal of Economic Entomology, Vol. IV, p. 142 and Bulletin 189, Kansas Agr. Expt. Station. CHAPTER XI INSECTS INJURIOUS TO CLOVER AND ALFALFA.* The Clover Root-borer f The Clover Root-borer is practically the only insect pest which seriously injures clover roots. It has long been known as a clover pest in Europe, but was first noticed in this country in western New York in 1876, whence it has spread southward to West Virginia and westward to Illinois and southern Michigan, and has also been injurious in Oregon. Life History. — During the winter the beetles may be found hibernating in their burrows in infested clover roots. They are not readily distinguishable, for they are scarcely one-eighth Fig. 158. — ^The clover root-borer {H7jlastinus obscurus): a, adult, natural size at right; b, larva or grub; c, pupa — much enlarged. (After Webster, U. S. Dept. Agr.) inch long, and are of a reddish-brown color much like that of the burrow. With the warmer weather of spring they commence * See The Insect Pests of Clover and Alfalfa, J. W. Folsom, 25th Report of the State Entomologist of Illinois, pp. 41-124, and Bulletin 134, Illinois Agr. Expt. Station. t Hylastinus obscurus Marsham. Family Scolytidae. 189 190 INSECT PESTS OF FARM, GARDEN AND ORCHARD burrowing and feeding in the roots, and during late May and early June the females deposit their eggs along the sides of the tunnels. "The female gouges out a shallow cavity, more often in the crown of the plant, sometimes at the sides of the root even 2 or 3 inches below the crown, and in this places singly, but not far separated, about a half dozen pale whitish, elliptical, very minute eggs. These hatch in about a week, and the larvse for a time feed in the excavation made by the mother, but soon burrow downward into the root, and before the 1st of August, the majority of them have become full-grown, and passed into the pupal stage. By October nearly all have become fully developed beetles, but they make no attempt to leave the plant until the following spring." The spread of the insect occurs very large- ly in the spring when the beetles fly from field to field, seeking uninfested plants in which to perpetuate their kind. It has been observed that alsike clover is not so badly injured as the mammoth and common red clover, on account of the fibrous roots and the tendency of its tap- root to divide. In Europe alfalfa is injured, but little injury has yet been reported to that crop in this country, as yet. "While an infested clover plant sooner or later succumbs to an attack by this in- sect, life may be lengthened or shortened by meteorological conditions. Thus, if the showing work of clover gpHng or early summer is very dry, the root-borer. Slightly en- ^ ^^ , . /, . ^. ,\ • r larged. (After Web- plants begm to dry m patches late m June, ster,) U. S. Dept. Agr. ^s soon as the hay crop is removed; but if there is much rain during this period, the weakened plants may continue to live until winter, dying out before spring. In either case the farmer is likely to be misled and attribute the loss to the weather." Clover is practically exempt from attack the Fig. 159. — Clover root INSECTS INJURIOUS TO CLOVER AND ALFALFA 191 first year as the roots are not large enough to accommodate the insects, and it is not until the second year that the plants are destroyed. Control. — The only effective means of control suggested is summer fallowing as soon as the hay crop has been removed. Fig. 160. — Present known distribution in the United States of the .clover-root curculio. (After F. M. Webster, L. C.) The field should then be plowed up at once, before the larvse have transformed to pupse, so that the hot sun, and dry winds, Fig. 161.— Stages of the clover-root curculio. (After Webster, L. C, from Wildermuth): a, adult; 6, larva; c, pupa. will dry out the roots of the clover and thus starve the larvae, thereby preventing their developing and migrating to other fields. Clover fields should not be allowed to stand over two 192 INSECT PESTS OF FARM, GARDEN AND ORCHARD years in infested localities. No injury seems to be done in pas- tures. A system of rotation in which the crop is mowed for hay and seed the first year, and pastured and then broken up the second year, should keep the pest under control. An insect very similar in life-history and nature of injury is the Clover-root Curculio.* This insect is also a snout beetle but belongs to a different family. In spite of this, the adults and larvae will both probably be confused by the ordinary observer. The curcuHo has been observed working on alfalfa. f The Clover Leaf-weevU t The clover leaf-weevil is a stout, oval beetle, about one-third inch long, with a long, thick snout. It is of a brownish color, with several narrow gray lines above and broad gray stripes on each side, and with twenty rows of small, deep punctures on the wing-covers. It also is a native of Europe and made its first appearance in the same section of western New York as the last species, about 1881. Since then it has spread eastward to Rhode Island and Vermont, southward to North Carolina and West Virginia and westward to Wisconsin and Illinois. Every few years the weevils and their larvae destroy much of the foliage in restricted localities, but rarely are they very injurious the next season. Red clover, alfalfa, and white clover are preferred in the order named; in Illinois the mammoth and alsike are also eaten. Life Hitsory. — In early fall the female beetles lay their eggs in crevices among the stems near the base of the plant, which hatch in from three to six weeks. The young larvae which hatch from them are without legs, but manage to climb by means of the prominent tubercles on the lower surface of the body. They are light yellowish-green, becoming deeper green as they grow older, the head is brown, and down the middle of the back is a white or pale yellow stripe bordered with reddish. The larvae become partially grown before winter sets in, when they hiber- nate in rubbish or just under the soil until spring, when they continue to feed upon the foliage and become full-grown in May and early June. They feed mostly at night and are hardly * Sitones hispidulis Fabricius. Family CurculionidcB. t See F. M. Webster, Farmers' Bulletin 649, U. S. Dept. of Agr. J Phytonomus punctatus Fab. Family Curculionidoe. INSECTS INJURIOUS TO CLOVER AND ALFALFA 193 noticeable in the day, when they he protected around the base of the plant, lying curled up head to tail. The injury to the foliage is quite characteristic, the edges of the leaves being eaten in a regular manner as shown in Fig. 162. When full grown the larva buries itself just under the surface of the soil and makes an oval cell, in which it spins a delicate cocoon consisting of a coarse network of pale yellow threads, which later turn brown, Fig. 162. — Clover leaf -weevil {Phytonomus pundatiis Fabr.) : a, egg magnified and natural Size; bbbb, larvae; c, recently hatched larva; d, head of larva; e, jaws of the same; /, cocoon; g, same magnified to show the meshes; h, pupa; i, weevil, natural size; j, the same magnified; k, top view of the beetle; I, tarsus and claws of the beetle; m, antenna of the beetle. (After Riley.) as shown in Fig. 162, Occasionally the cocoon is made on the surface or among the bases of the stems. In this the pupal stage is passed, lasting two or three weeks; the beetles being most common in July and August. The damage which the beetles do to the second crop of clover is fully equal that done by the larvae to the first, and is more apparent because the soil is then dry and the plant grows more slowly. 194 INSECT PESTS OF FARM, GARDEN AND ORCHARD That this insect has not become a more serious pest is due to the fact that as often as it becomes excessively abundant the larvae are almost completely destroyed by a fungous disease.* When affected by this disease the larvae climb to the top of a blade of grass, curl tightly around the tip, and soon die, first becoming covered with a white mold and then turning to a jelly- like mass. The spores of the fungus become scattered to healthy individuals, which soon succumb, so that before long nearly all are destroyed, and rarely do enough survive to cause trouble the next year. Frequent reports are received of poisoning of cattle which have fed on clover having numbers of the larvae which have died from this fungus. Accounts vary, some reporting serious sick- ness and even death as the result and others, probably more authentic, reporting merely temporary sickness. In any case, it will be well to keep cattle from the infested plants. Control. — On account of this disease repeated injury has been so rare that no means of artificial control has been necessary. "The necessity for the employment of any remedy does not appear until the clover is well on in its second year's growth," says Dr. Folsom (I.e.). "If damage is anticipated, however, it would seem advisable to pasture the clover lightly or to clip back in the spring; this does not hurt the clover, is highly desir- able as a means of forestalling the attacks of some other clover pests (see page 201), and might check the larvae of the leaf-weevil somewhat, though it is possible that they would subsist on the cut stems until the new growth started; and in cold weather they can live a long time without any food. After the second season red clover should be plowed under to get rid of this pest, as well as for other agricultural reasons." The Alfalfa Weevil f In recent years a first cousin of the last species has been introduced into Utah, where it has become firmly estabhshed and promises to become the most serious obstacle to alfalfa culture. The alfalfa weevil is a native of Europe, western Asia, and northern * Em'piLsa sphceroperma Fres. t Phytonomus posticus Gyll. Family Curculionidce. See E. G. Titus, Bulletin 110 and Circular 10, Utah Agr. Exp. Sta., and ^F. M. Webster, Circu- lar 137, Bureau of Entomology, U. S. Dept. Agr. INSECTS INJURIOUS TO CLOVER AND ALFALFA 195 Africa, where it is common but never very seriously injurious. It was first noticed in America near Salt Lake City, Utah, in 1904, and has been increasing and spreading until it now occupies an area of fully 100 square miles around Salt Lake City. The beetles are from one-eighth to three-sixteenth inch long, dark brown, marked with black and gray hairs which gives them a mottled appearance as shown in Fig. 165. These hairs or scales are gradually rubbed rCB. I MAR. I APR. I MAY JUNE JULY | AUcT SEPT. | DCT. syvM 'A\aVX ^^y^t^^^ggr^g^VBa'^SAl &55a (jf^iifi^ -p^C^; p.Wm\,ar^r>o -nLA»VX. Fig. 163. — Chart showing the life history of the Alfalfa Weevil. (From H. R. Hagan, Utah Agr. Expt. Sta. Circular 31. off, SO that in spring many individuals are entirely black with small grayish spots. Life History. — The beetles seek shelter for hibernation before frost in the autumn, either in the crowns of the alfalfa plants, or under thick grass, weeds, rubbishy leaves, or in hay or straw stacks. Often they winter in barns where the hay is stored, the floors of which are often found covered with the beetles in winter and spring. Ifc is estimated that fully 80. per cent of the weevils survive the winter in Utah. In the spring the beetles emerge and attack the young alfalfa plants as soon as there is sufficient food for them, usually late in March. The females commence laying eggs in early April and continue oviposition until early July. In early spring while the plants are small the 196 INSECT PESTS OF FARM, GARDEN AND ORCHARD females often push their eggs down between the leaves, but the usual method is to insert them in punctures made in the stem. This puncturing of the young stems often re- sults in considerable damage in early spring. A single alfalfa plant which had escaped from cultivation was found to contain 127 of these punctures, and as each puncture contains ten or fifteen eggs, this plant probably bore some 1200 eggs, although it was exceptional. The eggs hatch in about ten days and the small white larvse make their way to the leaves in which they eat small holes. They soon turn a decidedly green color, and when full grown are about one-half inch long with a white stripe down the middle of the back Fig. 164. — The alfalfa weevil, adults, clustering on and attacking sprig of alfalfa — natural size . (After Webster, U. S. Dept. Agr.) Fig. 165. — The alfalfa weevil {Phytonomus posticus): a, eggs; b, cocoon; c, larva; d, pupa; e, adult — all much enlarged. (After Webster, U. S. Dept. Agr.) INSECTS INJURIOUS TO CLOVER AND ALFALFA 197 and somewhat curved as shown in Fig. 165. They attack the young leaves and crown so that a badly infested field will not get over six inches high; too short to mow. The larvae are most abundant in May and decrease through June. When full grown the larvae crawl or drop to the ground and spin their cocoons in the dead leaves or rubbish. The cocoon is globular and com- posed of a network of rather coarse white threads, Fig. 165. In it the larva transforms to a pupa, which stage lasts from one to two weeks, when the adult beetle emerges. From early to midsummer the beetles become more and more abundant, and not only feed on the fresh growth, but attack the bark of the stems so that where excessively abundant they totally destroy the second crop. "The entire life of the insect, from the deposition of the egg to the emergence of the adult, may be anywhere from forty to seventy days, while the beetle itself may live, including the winter, from ten to fourteen months." — Webster. Inasmuch as literally milHons of the beetles have been gath- ered by machines from a single acre, and as the beetles have been found in considerable numbers on freight and passenger trains, it is highly probable that the pest will be spread by the several trunk-lines of railroad which pass through the infested region, as in many places alfalfa has escaped from fields and grows as a weed along the railway tracks. It is, therefore, highly important that alfalfa growers be on their guard against this pest and take prompt measures for its destruction wherever it may gain a foothold. The weevils also spread rapidly by flying in spring and summer, which migration is aided by the winds. They may also be spread in articles shipped from an infested region and on wagons or automobiles. Control. — The methods of control have not, as yet, been satisfactorily determined, though the entomologist of the Utah Agricultural Experiment Station, E. G. Titus, from whose report the following summary is taken, has made extensive experiments with various methods. Old alfalfa fields are always worst injured, and fields should not be left down in alfalfa over about seven years. Thorough disking in the early spring has proved to be one of the essential factors in securing a good crop, as it increases the stand and 198 INSECT PESTS OF FARM, GARDEN AND ORCHARD stimulates a quick growth which enables the plants better to withstand the weevil injury. The use of a brush drag with which a spike-tooth harrow is combined has been found an excellent means of kilhng the larvae, as they are knocked to the ground and large numbers killed by the fine dust. If the field is very hard it is advisable to disk it before using the drag. After the use of the drag, the fields should be watered where there is irrigation. In summarizing the methods of control, Professor Titus recommends: " That alfalfa be disked in early spring to stimulate it to better growth. That the first growth be cut when the most of the eggs have been laid (middle of May) and then brush-drag the field thoroughly. Fields should be brush-dragged again after the first crop has has been cut. All weeds and rubbish should be clean- ed from the fields, yards, ditches and fence rows so that there will be less op- portunity for the weevils to find winter shelter. Alfalfa should not be allowed to grow more than seven or eight years in infested districts." Quarantine measures to prevent the spread are matters of local and state jurisdiction but are of the highest importance to the alfalfa growers of the country. Fig. 166.- -The Clover-mite pratensis). {Bryohia The Clover-mite * The Clover-mite is nearly related to the common red spider of greenhouses, with which it is often confused, belonging to the same family of vegetable-feeding mites. It is, however, about twice the size of the red spider, being four one-hundredths inch * Bryohia -pratensis Garman. Family Tetranychidoe. See C. L. Marlatt, Circular 19, 2d Ser., Division of Entomology, U. S. Dept. Agr. INSECTS INJURIOUS TO CLOVER AND ALFALFA 199 long. Though known as the clover mite, on account of its feed- ing upon that plant, yet this insect was first known as, and is still, an important enemy of fruit-trees, more especially on the Pacific coast, but also in other sections of the country. The most injury seems to have been done to clover in the Central States as far south as Tennessee, though it has suffered somewhat even in the East. When attacked by the mite the leaves of clover or fruit- trees become yellow and have a sickly appearance, as if affected with a fungous disease. Especially upon the upper sides of the tender leaves of clover the juices are extracted over irregular areas, looking more or less hke the burrows of some leaf-mining larvae. Owing to the small size of the mites they may be doing considerable damage to the foliage and yet remain unnoticed; but in the egg stage the pest is much more readily detected and attacked. In the more northern States the eggs are laid in the fall, and do not hatch until the next spring. Farther south, however, the adult mites hibernate over winter. The eggs are of a reddish color, laid upon the bark of trees, especially in the crotches, and in the West are sometimes so thickly placed as to cover considerable areas two or three layers deep. When the adult mites leave the clover-fields in the fall to find hibernating quarters upon fruit-trees for the winter, they often become quite a nuisance by invading dweUing-houses which are in their path. This is more particularly the case throughout the Mississippi Valley. Remedies. — The only practical way of protecting clover from the mite is by destroying the eggs and hibernating mites upon the fruit-trees in winter. This may be done by burning all the prunings and thoroughly spraying the trees with kerosene emul- sion diluted with five parts of water, or with miscible oils or lime-sulfur mixture. Such a spraying will also protect the fruit- trees from the mite, and will destroy numerous other insects, such as the pear-leaf blister-mite, which hibernates upon the trees. Such small insects, so minute as usually to escape notice, are often responsible for a poor growth, and should be properly checked whenever known to be injurious. 200 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Clover-seed Midge * The Clover-seed Midge seems to occur wherever red and white clover is grown in this country, and is a pest which must be taken into consideration in raising seed, for frequently it is not recognized as the cause of the failure of the seed crop. Alsike clover, and probably mammoth clover, is practically uninjured, as it flowers enough later to escape attack, nor is alfalfa infested. Life History. — The parent of all this trouble is a small midge, one-twelfth inch long, with black head and thorax and reddish Fig. 167. — ^The clover-flower midge (Dasyneura leguminicola): a, enlarged side view of female, with scales denuded, to show more clearly the struc- ture; b, head, more highly magnified, to show structure of the eye, palpi, and basal joints of antennae; c, tip of ovipositor, highly magnified and showing at end of next to last joint the manner in which it is clothed with minute hairs; d, highly magnified antennal joints, their minute hairy clothing shown on the lower one; 2, a, larva enlarged, ventral view; h, head retracted, highly magnified. (After Riley.) abdomen, so small, indeed, that it will rarely be noticed. The antennse have sixteen or seventeen segments, and the wings have but few veins, as shown in Fig. 167. The female bears a slender retractile ovipositor Avhich, when extended from the tip of the abdomen, is fully as long as the body, while the tip of the abdomen of the male is furnished with clasping organs. The midges appear in late spring just as the clover commences to head. The eggs are laid among the hairy spines of the clover- head or beneath the bracts around it, are yellowish to orange * Dasyneura leguminicola Lintner. Family Cecidomyiidce. Also called the Clover-flower Midge. See Farmers' Bulletin 971, U. S. Dept. Agr. INSECTS INJURIOUS TO CLOVER AND ALFALFA 201 in color, of an oval shape, and about one one-hundredth inch long. Upon hatching the maggot works its way into the open end of a floret, where it sucks the forming seed, and prevents the petals of the floret from expanding, so that although some of the flowers in the head will bloom, the field as a whole does not blossom as usual. The maggot is footless, white to orange- red in color, and about one-tenth inch long when full grown. Upon becoming grown in late June and the first week of July the maggots enter the soil and just below the surface make tough, oval, silken cocoons, in which they pupate. The pupal stage lasts about three weeks or more, and the flies of the second generation appear in Central Illinois in late July and early August, being abundant as the second crop of clover heads appear. The eggs are laid in the clover heads and hatch in about three days, and the second generation of maggots do the worst damage to the seed in late August and early September; in the same manner as did the first generation. They become full grown by frost and either hibernate as full-grown larvae, in which case they pupate early the next spring, or pupate before frost and pass the winter as pupae in the soil. Control. — Fortunately this pest may be very readily controlled by adapting the methods of harvesting so as to destroy the devel- oping maggots. If clover is grown alone it should be cut early before the maggots have become mature This results in drying, up the food plant and thus destroying the larvae and hastens the development of the second crop of clover heads, so that the midges of the second generation have but few green heads in which to lay their eggs. Cutting need not be done until the field is fairly fresh with bloom, but should not be delayed until the flowers commence to wither. Where timothy and clover are grown together they should be pastured lightly or chpped back in May, which will result in bringing both the first and second blooming after the greatest abundance of the midges. As the midges do not travel far, it would seem advisable to "prevent the sporadic heading of first-year clover by mowing it back a few weeks after small grains have been harvested, at a time when growth is vigorous, but yet sufficiently early to permit considerable growth before frost sets in. Volunteer clover should always be cut, as it affords a rich nursery for all kinds of clover insects." — Folsom. 202 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Clover-seed Chalcid * Evidence accumulates that the shortage of the clover-seed crop may frequently be due to the larva of a little chalcis-fly which hollows out the ripening seed, leaving it brown, brittle and hollow, so that the af- fected hulls are blown away with the chaff in threshing. As there is no evidence of the pest in the appearance of the heads, and as the worst affected seed is thus overlooked i n threshing, its work will often evade detection. Fig. 168. — The clover-seed chalcis {Bruchophagus funebris): adult female, much enlarged; antenna of male at left, more enlarged. (After Webster, U. S. Dept. Agr.) If the seed crop is short it will be well to examine seed for the larvae; many of the seed will be found shriveled and misshapen, and frequently considerable numbers of the adults will issue from the seed soon after threshing. The adult is a small, wasp-like fly one-twelfth to one-sixteenth inch long, black in color, and with four wings, the hind-wings very small and the fore-wings with but a single vein. It belongs to a family almost all of which are parasitic on other insects, and for many years it was thought to be a para- site of the clover-seed ^/,, W midge, until its true role was discovered. In recent years exam- inations o f ripening heads from all parts of the country show it is ° ^ " ^ nrnhflhlv Hiqfribiitpd Fig. 169.— The clover-seed chalcis: a, egg— highly probably dlStribUtea j^^gnified; 6, larva an, head more enlarged; c, wherever clover is pupa — much enlarged. (After Webster, U. S. grown and that from Dept. Agr.) * Bruchophagus funebris Howard. Family Chalddidoe. INSECTS INJURIOUS TO CLOVER AND ALFALFA 203 20 to 80 per cent of the seed is often destroyed. Both red and crimson clovers are attacked, and a recent bulletin * from the Department of Agriculture states that the insect is actually threatening to destroy the alfalfa seed industry in certain sections which formerly produced it in quantity. Life History. — The winter is passed by the fully grown larvae in seed on the ground. The adults emerge in the spring, the maxi- mum appearing about June 10th in central Illinois, according to Dr. Folsom, to whom we are indebted for the most careful study of the pest. The females deposit their eggs in the soft seed, just as the floret is withering, being unable to penetrate the seed after it has hardened. The egg is whitish, about .01 inch long, and with a peculiar tail-hke appendage (Fig. 169). The maggot-like larva feeds upon the seed, gradually hollowing it out, and when full grown is about one-twelfth inch long, stout and footless, with a small head. The pupal stage is passed within the seed and a second generation of adults emerges about the middle of August. These lay their eggs in the second growth, and some of the adults from these appear the same season and the rest not until the following year. There seem to be at least three generations a year in central Illinois, but the life history is com- plicated by the irregularity in the time of development, though the greatest numbers of adults appear about June 10th and August 10th, just as the clover-seed is green. Control. — Mr. T. D. Urbahns, in the bulletin mentioned, recommends cutting the seed crop promptly and stacking it as soon as possible, using well cleaned seed, destroying burr-clover and cleaning up of waste land as well as destruction of screenings from the thresher and winter cultivation as being practices likely to reduce the damage from the chalcis. He particularly recom- mends that infested crops be harvested, even if they are of no value for seed, since, if they are left standing and pastured they will infest a whole locahty. The Clover-seed Caterpillar f "In its ability to diminish the seed crop, this pest ranks with the seed-midge and the seed-chalcid. Attacking a clover head that is green or partly in bloom, the httle caterpillar eats out a * Farmers' Bulletin 636, U.JS. Dept. Agr. t Enarmonia interstinctana Clem. Family Grapholithidce. 204 INSECT PESTS OF FARM, GARDEN AND ORCHARD cavity in the head, destroying many of the unopened buds and some of the tender green seeds, and spoihng the head as a whole. When no young clover heads are at hand, the caterpillar feeds on tender green leaves at the crown of the plant." — Folsom. Red clover is the principal food plant, but white, alsike, and probably mammoth clovers are also affected. The published records show that it occurs in the Northeastern States southwest to Missouri, but it doubtless occurs elsewhere where clover is grown, as it might readily be carried in hay. Life History. — The adult is a pretty Uttle brown moth, with a wing expanse of two-fifths inch, with silvery markings as shown in Fig. 170, the most conspicuous marks forming a double crescent when the wings are closed on the back. The moths appear about the end of May in central Illinois, or just as the clover is coming in- to bloom, being active in early evening, when the females lay their eggs in the heads. The egg is circular in shape, about .01 inch in diameter, yellowish-white in color, and hatches in five or six Fig. 170— Clover-seed caterpillar {En- days. In first-year clover that has annonia interstindana): a cater- ^ot headed and in second-year pillar: o, pupa; c, moth, all much enlarged: d, moth natural size, clover recently c u t , the eggs are (After Osborn.) jg^j^j ^^ young stems and leaflets at the base of the plant, where the larvae stay. "Hatching usually at the base of a green clover-head; the larva eats into the head, destroying the green florets as it goes. A small green head is often destroyed entirely, before it is many days old; a larger head is injured only locally at first, remaining green on one side, while the other and unaffected side may come into full bloom." Judging from the appearance of the head the work might be that of the seed-midge, but whereas it is hidden away in a single floret, this caterpillar makes a large dirty excava- tion involving many florets, and is readily found by tearing open the head. The caterpillar attacks the bases of the florets, includ- ing the semifluid ovules, but does not attack seeds which have INSECTS INJURIOUS TO CLOVER AND ALFALFA 205 hardened. "Even when the direct injury is confined to a portion of the clover-head, the entire head is ruined, for it at length dries up and loses the rest of the florets, leaving only the dead and brown receptacle. Less conspicuous, though not inconsiderable, is the injury at the crown of the plant, done chiefly in September and October, by caterpillars of the same species feeding upon the leaves." — Folsom. The total injury varies greatly, but not infre- quently 20 per cent of the heads are infested, and in Iowa infesta- tion has sometimes been exceedingly severe. In any event, every head destroyed means the loss of more than one hundred seeds. The larvse become full grown in four to five weeks. The full grown caterpillar is about one-third inch long and varies in color from dirty-white tinged with green to orange, according to the food. The larva spins an oval white silken cocoon, two-fifths inch long, either in the head or at the surface of the ground, which is more or less covered with bits of excrement and floral tissue. The pupa is one-fifth inch long, brown, with the thorax and wing-cases darker, and with two transverse rows of teeth on the back of the abdominal segments except the last, which bears six stout blackish hooks at the tip. The pupal stage lasts two to three weeks and a second generation of moths emerges about the third week of July (in central IlHnois). The hfe cycle is repeated in the same manner and a third generation of moths appears about September 1st. The larvae of the last brood feed either in immature clover-heads or at the crown of the plant. Most of them become full grown and transform into pupae, in which stage they hibernate over winter, while others become full grown, but fail to pupate and hibernate under rubbish. Control. — Cutting and storing the hay crop early in June as advised for the clover-seed midge will kill the larvae while still in the heads. "The hay should be handled hghtly and stacked or stored as soon as possible. Osborn and Gossard * have at- tested the value of this method, and have given these further recommendations: (1) Cut volunteer clover m early June and dispose of the heads speedily; (2) do not allow clover to run for more than two years; (3) sow seed on land remote from old fields; (4) pasture clover in the fall of the first year; (5) plow * Osborn and Gossard, Insect Life, Vol. IV, p. 254; Bulletins 14 and 15, Iowa Agr. Exp. Sta.; 22d Report Entomological Society of Ontario, p. 74. Gossard, H. A., Bulletin 19, Iowa Agr. Exp. Sta. 206 INSECT PESTS OF FARM, GARDEN AND ORCHARD an old clover-field under in October or November or in early- spring, then harrow and roll. These practices operate at the same time against several other clover pests." — Folsom. The Clover-hay Worm * The Clover-hay Worm attac^ks stacked or stored clover, par- ticularly where it is held over a year or where placed on old hay, eating much of the lower layers and rendering it unfit for food. - -t-i ■ 4 1 ^'^'^yf- ^^*^=*'^«*i^-^ Fig. 171. — Clover-hay worm, greatly enlarged. (After Folsom.) It has been known to be injurious from Kansas eastwaid, but occurs throughout most of North America, as well as parts of Europe, Asia, and Africa. Fig. 172. — The clover-hay worm moth, wings expanded (after Folsom) and at rest (after Pettit) — enlarged. "The larvae attack the bottom of a clover stack to a height of 2 feet or more from the ground; similarly, in the barn, they occur next the floor. They interweave the hay with white silken webs, intermixed with black grains of excrement. . . ; they reduce much of the hay to chaff, and their webs give the hay * Hypsopygia costalis Fab. Family Pyralididce. INSECTS INJURIOUS TO CLOVER AND ALFALFA 207 the appearance of being mouldy; in fact, such hay actually becomes mouldy if it has been lying near the ground. This hay is refused by horses and cattle and is fit only to be burnt. When the hay is removed, swarms of wriggling brown caterpillars are left." The work of the caterpillars is usually noticed in late winter and spring. Life History. — The moths appear from the middle of June until early July in the Northern States and most of the first generation have disappeared by the end of July. The moths have a wing expanse just under an inch, with silky, wings tinged with purplish above, margined with orange and fringed with golden-yellow. On each side of the fore-wings are two large, golden spots which divide the anterior margin into thirds and continue backward as narrow lilac lines (Fig 172). The hind- wings are marked by two transverse, wavy, straw-colored lines. As soon as some clover-hay is found the female deposits her eggs and the caterpillars feed upon it. When full grown they are about three-quarters inch long, of a dull-brown color. The segments are divided by a transverse groove, and each bears several shining areas, with a fine white hair in each. White silken cocoons, one-half inch long, covered with bits of hay and excrement, are made by the larvae in the hay or in cracks and crevices of the barn, in which they transform to pupae, which are of a honey-yellow color, with the parts clearly defined by the darker color of the sutures. The moths of the second brood emerge from the middle of August until September 1st, but may be found flying until late October. Caterpillars of all sizes may be found in barns throughout the winter and pupate in the spring. Control. — Usually no serious injury is done except where clover-hay is kept over the second year or longer. When it is fed out each spring, before the next crop is harvested, there is no food for the young caterpillars, and they perish before the new crop comes in. Consequently mows should be cleaned out each spring. New clover-hay should never be placed on top of old hay, and stacks should be placed at some little distance from the old stacks if possible. Burn up the refuse from old stacks, or what remains in the bottom of the mow. Stacks should be raised above the ground on a foundation of logs or rails, so as to keep the bottom as dry and cool as possible, as 208 INSECT PESTS OF FARM, GARDEN AND ORCHARD the caterpillars love warmth and moisture. It has been found that salting the hay for 2 or 3 feet at the bottom will prevent injury, and many farmers salt their clover-hay, using about two quarts of salt to the ton. The Clover Leafhopper * The Clover Leafhopper is an insect which may be found in clover and alfalfa fields over a wide range. It is a very small insect, hke most common leafhoppers, and its injury is widely distributed, so that it often attracts no notice, but is none the less real. The insects are slender forms, one-eighth inch in length and of a grayish color with darker markings. They hop actively when disturbed and may, at times, be noticed in clouds when one walks through a clover field. Injury. — The injury is caused in two ways. First, they suck the sap from the stems and foliage of the plant and, later, they »U\.vo\tA(X Fig. 173. — The clover leaf hopper (Agallia sanguinolenta) : a, adult; b, nymph, side view; c, nymph, dorsal view; d, face; e, elytron; /, female geni- talia; g, male genitalia. All enlarged. (After Osborn and Ball, from Gibson, I. c.) puncture the tissues and deposit their eggs within them, the result being irregular swellings which interfere with the growth. Life History. — There are at least three generations but they are more or less indistinguishable on account of over-lapping. They hibernate as adults. The young or nymphs resemble the adults in a general way but are greener in color and less active. Control. — Clean culture, burning of rubbish in the fall and early cutting of the clover and alfalfa as well as close pasturing * Agallia sanguinolenta Prov. Family Jassidos. INSECTS INJURIOUS TO CLOVER AND ALFALFA 209 of grass lands while the adults are numerous are the Bureau of Entomology recommendations for control.* When leafhoppers are unusually numerous and destructive they may be captured in enormous numbers by the use of a hopperdozer or hopperette, constructed along the same lines as those used for grasshoppers. Miscellaneous Insects of Clover and Alfalfa In addition to the insects already discussed there are many others which attack these crops, either occasionally or regularly. Among these should be mentioned the grasshoppers, a complete discussion of which will be found in Chapter VII, the pea-louse, Fig. 174. — The alfalfa caterpillar: full-grown larva. Enlarged about three diameters. (After Wildermuth, 1. c.) which is fully discussed in Chapter XV, and the bhster beetles, also discussed in Chapter XV and the one following and in Chap- ter VII. Besides these there are several species of caterpillars found in greater or less abundance in clover and alfalfa at all times. These include the following: The Alfalfa Caterpillar f which is the larva of one of our most common yellow butterflies always associated with clover fields and so familiar to all as to need no description. The larva is green in color and similar to the common cabbage worm, dif- fering in the possession of a light stripe on each side through which runs a bright red hne. The insects seem to hibernate in all stages and there are two or more broods. Damage to the crops is usually not severe in any one place but evenly distributed and aggregates more than would be sup- * See Farmers' Bulletin 737, U. S. Dept. Agr. t Eurymus eun/theme Boisd. Family Pieridae. See V. L. Wildermuth, U. S. Dept. Agr. Bulletin 124. 210 INSECT PESTS OF FARM, GARDEN AND ORCHARD posed. In some localities damage is severe and control measures must be employed. When this is necessary the following prac- '^^y^iy^km^j'^^^yi:' ' '^ "^K / /^' Fig. 175. — Map showing distribution of the alfalfa caterpillar. (After Wildermuth, 1. c.) tices are advisable: Cut the crop early and close to the ground; pasture closely where possible; disk badly infested fields and Fig. 176. — Map showing distribution of the green clover worm in the United States. After Hill.) then run over them a roller or a brush drag; keep cultural con- ditions in a high state of perfection at all times. INSECTS INJURIOUS TO CLOVER AND ALFALFA 211 The Green Clover-worm * is another caterpillar which is frequently abundant in fields of clover, aKalfa, soy beans and related crops. It is a green caterpillar with darker stripes, an inch or more in length and the larva of one of the common dull- colored moths of the cutworm type. It is best controlled by harvesting the crop when the worms are present in the greatest abundance but are not quite grown, whether the crop is quite ready to cut or not. In this way many are starved and others perish from exposure to the sun after the crop has been removed. Supplement this with the brush drag if the worms are especially numerous. The AKalfa Looper f is one of the serious occasional pests of alfalfa in the Northwest. It is abundant mainly in irrigated regions. Control measures recommended are similar to those for the green clover-worm and al- falfa caterpillar and are at times supplemented by the ^^'™°*" ^^ use of poisons. Fig. 177.— The green clover worm; adult or The Garden Webworm ™°^^- ^^^^^ enlarged. (After Hill). (See Chapter XIX) sometimes defohates alfalfa and related plants and leaves over the injured stalks the webs which serve to identify it. Control measures apphcable to it are ahnost exactly similar to those for the other caterpillars Usted. * Plathij'pena scabra Fabr. Family ' Noctuidae. See Farmers' Bulletin No. 982, U. S. Dept. Agr. t Autographa californica Speyer. Family Noctuidae. See J. R. Parker Jour. Econ. Ent., Vol. 8, No. 2, 1915. CHAPTER Xir INSECTS INJURIOUS TO TOBACCO * The Tobacco Flea-beetle f The Tobacco Flea-beetle is one of the important pests of that plant throughout the Middle States, being particularly injurious to young plants. The beetles damage the leaves by eating small holes in the upper or un- der surfaces, or clear through them, so that when badly eaten the leaves look as if they had been peppered with shot. The little beetles which do this damage are hardly more than one-twentieth inch long light brown in color, with a dark band across the wing- covers. A few of them could Fig 178.— Tobacco flea-beetle (^pz^no; par- do but little damage, but they vula): a, adult beetle; b, larva lateral . . , view; c, head of larva; d, posterior leg soon mcrease m numbers, so of same; e, anal segment, dorsal view; that they SWarm over the /, pupa— a, 6, /, enlarged about fifteen . times; c, d, e, more enlarged. (After leaves and mjure them badly. Chittenden, U. S. Dept. Agr.) Similar injury is done to potato, egg-plant, and tomato, and the beetles also feed on horse- nettle, nightshade, and Jamestown weed. Life History — The eggs are laid in the soil and the larvae feed upon the roots of common weeds, such as the nightshade and Jamestown weed. The larva is dehcate, thread-like and white, * See L. O. Howard, Farmers' Bulletin 120, U. S. Dept. Agr., The Prin- cipal Insects Affecting the Tobacco Plant. A. C. Morgan, Circular 123, Bureau of Entomology, U. S. Dept. Agr.; Yearbook, U. S. Dept. Agr., 1910, pp. 281-296; and Z. P. Metcalf, N. C. Dept. of Agr. Bulletin, Oct., 1909. t Ejntnx parvula Fab. Family Chrysomelidae. INSECTS INJURIOUS TO TOBACCO 213 except the yellowish head, and about one-eighth inch long. It pupates in the soil. When the beetles become very numerous the larvae some- times develop on the roots of tobacco, but rarely do serious damage. The life history has not been determined exactly, but the full life cycle seems to occupy about a month, so that there are probably several generations in a year. Control. — Inasmuch as the larvse develop on the roots of the weeds mentioned, it is evident that they should be kept down by thorough cul- tivation. Where the beetles appear, the plants should be sprayed or dusted with Paris green, or probably better, arsenate of lead, the same as for the horn-worm. Dipping the plants in arsenate of lead, 1 pound to 10 gal- lons of water, just as they are set, has been found to afford very satisfactory protection in Connecticut. The Tobacco Stalk-worm * Professor W. G. Johnson found this' species, also known as the Corn-root Web worm, to be a serious pest to grow- ing tobacco-plants in southern Mary- land, where it seems to have been a tobacco pest for a good many years, and it has also been noted in Delaware. The Injury.— The injury to tobacco Fig. 179.--T o b a c c o leaves . -1 , "i r, n T 1 damaged by Epitrix parvul. is described by Professor Johnson as (After Howard, U. S. Dept. follows: " The uninjured tobacco had -^sr-) a leaf spread of from ten to twelve inches. A few rods beyond, where the soil was not so gravelly and better, we found the larvse * Crambus caloginosellus Clem. Family Crambidce. See p. 161 and Bul- letin 20, n. s., Div. Ent., U. S. Dept. Agr., pp. 99-101, 1899. 214 INSECT PESTS OF FARM, GARDEN AND ORCHARD had literally destroyed the first and second plantings and were at work upon the third, damaging it severely, although the ground had been replanted before the last planting. Here and there was a young plant just beginning to wilt, and invariably we found the larva at work either in the stalk or at the base of the plant just below the surface of the ground. So far as I could ascertain, the attack is always at the surface or just below. In many instances the larvae had hollowed out the stalks from the base of the roots to the branches of the first leaves. Many plants were gnawed irregularly around the stalk below the surface, and some, in fact, were completely cut off at the surface, the insect always working from below. In the great majority of cases the larvae were found in a small mass of web near the plant, and sometimes within it. In one plant, less than six inches high, we found four larvae within the stalk, but as a rule only a single one was present." Professor Johnson concluded "(1) that it is most likely to occur over local areas in tobacco following timothy or grass; (2) that the character of the soil has little or nothing to do with its ravages; (3) that the attack upon corn is also a frequent occurrence in the same section; especially when following grass or timothy." Remedies. — He recommended "(1) that growers of tobacco avoid planting upon grass or timothy sod; (2) that where grass land is plowed down it would be well to put it in wheat, following with clover, before tobacco. If desirable, corn could follow the grass and the land could be seeded in crimson clover at the last working. This would serve a twofold object by revealing the exact location of larvifi in the area under cultivation by their attack upon corn, when they could be destroyed largely by frequent harrowing and rolling, and by affording a most excellent soil crop to turn down the following spring, which would be a decided advantage to the tobacco; that if it is found neces- sary to have tobacco following grass, it should be broken in the spring as early as possible, and frequently rolled and har- rowed, at the same tune delaying the setting of the plants as long as possible in order to destroy and starve the larvae within the ground." INSECTS INJURIOUS TO TOBACCO 215 The Spined Tobacco-bug * Professor H. Garman has found a small bug, which he has termed the Spined Tobacco-bug, doing more or less injury to plants in Kentucky, and as this insect is widely distributed throughout the country, it probably does more or less damage elsewhere, though never a serious pest. Concerning its work, he says: "Occa- sional plants in tobacco-fields are at times observed to have become suddenly wilted, the leaves hanging limp, much as if the stalk had been severed. After a time they recover again, and, beyond a temporary check on their growth, appear to have suffered but little injury. If such plants are searched carefully while still wilted, a flat, brown bug with each side of the body produced into an angle, or sharp spine, will be found upon the stalk along the base of the leaves. It is very shy and keeps out of sight, hence any Fig. 180. — The spined tobacco-bug {Euschistus variolarius), nymph at left; adult at right — enlarged. (After Howard, U. S. Dept. Agr.) brisk movement on the injured plants is likely to cause it to drop to the ground and conceal itself." These insects are true bugs, suck- ing their food through a beak, which is bent under the body between the legs when not in use. They are about half an inch long, of a drab color above and greenish or yellowish below. Usually only one bug is found on a plant, so that the best way to prevent the injury is to pick them from the plants, and keep down such weeds as thistles and mulleins, upon which such in- sects feed, in the adjoining fields. * Eutschistus punctipes Say (variolarius Pal. Beauv. See Bulletin No. 66, Ky. Agr. Exp. Sta., p. 33. Family Pentatomidoe. 216 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Homworms or Tobacco-worms * Of all the insects feeding upon tobacco, the Hornworms are the most widely injurious and therefore best known. The cater- pillars of two species of moths are commonly included under this popular name, both species occurring throughout the tobacco- growing States, the northern tobacco-worm being more common in the North and the southern tobacco-worm more common in the Fig. 181. — Northern tobacco-worm, or "hornworm" (Phlegethontius quinque- maculnta): a, adult moth; h, full-grown larva: c. pupa — natural size. (After Howard, U. S. Dept. Agr.) South. The differences in the adult moths may be readily appre- caited from Figs. 181 and 182, the southern form being darker and with brighter orange spots on the abdomen, and the white lines on the hind-wings being less distinct. The larvse of both species commonly attack tomato vines and are commonly called tomato worms where tobacco is not grown. * Phlegethontius quinquemaculata Haworth (Northern), and P. sexta Johanssen (Southern). Family Sphingidae. 216 INSECTS INJURIOUS TO TOBACCO 217 Life History. — The pupae pass the winter several inches below the surface of the soi) and from them the moths emerge in May and June, according to the latitude and season. The females deposit their eggs singly, upon the lower surfaces of the leaves, from which the little caterpillars hatch in from four to eight days. The char- acteristic work of the larvae is too well known to every tobacco grower to necessitate description. The caterpillars become full grown in about three weeks, during which time thev moult some FiQ. 182. — Southern tobacco- worm {Phlegethontius sexta): a, adult moth; b, full-grown larva; c, pupa — natural size. (After Howard, U. S. Dept. Agr.) five times. The full grown larvse are three to four inches long, of a dark green color with white stripes on the side of the body, those of the northern species having a V-shape, while those of the south- ern species being simple oblique hands. At the tip of the abdomen is a stout horn, from which is derived the name of hornworm, which in the northern species is black and in the southern is red. The pupae are formed in the soil, are dark brown, about two inches long, and have a peculiar handle-like process, the sheath of the 218 INSECT PESTS OF FARM, GARDEN AND ORCHARD proboscis, which somewhat resembles a horn and which may account for the name of " hornblowers," commonly given them in Marylar/d and Virginia. The pupal stage lasts about three weeks, when the adults emerge, the whole life cycle requiring from six to eight weeks. Usually two generations occur in a season through- out most of the tobacco belt, but in the North there seems to be but one generation, and in the Gulf States there may be three generations. Occasionally the worms are overlooked in cutting the tobacco and are carried into the barn, where they may do considerable injury even after the tobacco is partially dry. Control. — The most common method of control is hand-pick- ing, usually termed "worming." In seasons when the worms are not overabundant this may be the most practical method of con- trol, but it is both tiresome and expensive, and the planter has no means of predicting whether the worms will be more or less abun- dant. Large flocks of turkeys driven through the fields will aid most efficiently in this work. In many sections the worms are now controlled by spraying or dusting with Paris green or arsenate of lead. More or less popu- lar prejudice against the use of arsenicals has existed, as it was thought the tobacco might be poisonous to the consumer. Careful chemical examinations have shown, however, that the amount left on the foliage after three sprayings would be far too small to have any deleterious effect. The same prejudice formerly existed against the use of arsenicals on potatoes, cabbage and other crops but experience has shown it to be unwarranted. A real objection to the use of Paris green is that it sometimes slightly burns the foUage, so that arsenate of lead will doubtless be found preferable. Morgan* recommends dusting rather than spraying and con- demns the use of Paris green. His summary of recommendations is as follows : "Paris green, although an effective insecticide, frequently burns tobacco very severely and may reduce the value of the crop by as much as 50 per cent in exceptional cases. Arsenate of lead never seriously injures tobacco even under the most unfavorable conditions. A dosage of Paris green large enough to be effective against horn- worms can not be applied without grave danger of burning tobacco. * Morgan, A. C. Farmer's Bulletin 867, U. S. Dept. of Agr. INSECTS INJURIOUS TO TOBACCO 219 Paris green, which is applied in dust form without a carrier, is used at the rate of from 1 to 2 pounds per acre. Fig. 183. Hibernation of southern tobacco-worm ;c, pupa in hibernating cell in soil, at the depth of which pupation usually takes place in the stiff er soils; a, cross-section of pupal cell viewed from below; b, pupal cell showing entrance hole of larva — two- third natural size; (After A. C. Morgan, U. S. Dept. Agr.) Arsenate of lead is safe and effective during rainy weather, whereas Paris green is dangerousi and ineffective. 220 INSECT PESTS OF FARM, GARDEN AND ORCHARD It is recommended that arsenate of lead be used against the tobacco horn worms and that it be appHed as a dust or powder. The dosage of arsenate of lead in powdered form varies from 3^ pounds to 5 pounds per acre. If applied as a spray, use from 3 to 4 pounds in 100 gallons of water. To apply arsenate of lead in powdered form, without a carrier, use a dust gun having a fan diameter of at least 10 in<;hes and a special device for pre- venting clogging of the delivery pipe. If a gun with such a device is not used, it will be necessary to mix the arsenate of lead thor- oughlywith equal parts of dry wood ashes. Apply arsenate of lead when there is no breeze and when dew is on the plants. Use only such brands of arsenate of lead as are guaranteed to contain at least 30 per cent of arsenic oxid, of which not more than 1 per cent is free, or water-soluble.'' Natural Enemies. — Very frequently worms are found covered with what seem to be small, white eggs. These are not eggs, how- ever, but are the small silken cocoons of a little wasp-like parasite {Apan- teles congregatus) whose larvse feed I internally upon the juices of the worm and thus ultimately kill it before it transforms to a pupa. Such parasitized worms should never be Yig. 185.— Southern tobacco-worm destroyed, as the parasites are of with cocoons of parasite. 1 xi 4.U J 4.U (^^^r Garman.) more value than the damage the worm might do. Very frequently the caterpillars are attacked by a bacterial disease which causes them to turn dark and become shrunken and flaccid. Fig. 184. — Southern tobacco-worm killed by fungus. (After Garman.) INSECTS INJURIOUS TO TOBACCO 221 h Fig. 186. — The true budworm (Chloridea vire- scens): a, adult moth; b, full-grown larva, from side; c, same, from above; d, seed-pod bored into by larva; e, pupa — natural size. (After Howard, U. S. Dept. Agr.) The Budworms * Two caterpillars of the same genus commonly attack the bud of tobacco and have been distinguished by Dr. L. O. Howard as the true budworm and false budworm, the latter being the same as the well-known cotton boll- worm or corn ear- worm. f "The true budworm (Chloridea viresceJis) ' oc- curs in the more south- ern portions of the to- bacco-growing regions," says Dr. Ho ward, | " but has not been noted in to- bacco-fields north of Maryland. The adult insect is a small greenish moth, well illus- trated in Fig. 186. The larva or caterpillar of this moth, also illus- trated, is nearly always found in the bud of the tobacco-plant about the time the plant is ready to top. In some seasons they occur in large numbers and damage the tobacco considerably. In the early part of the season, as a general thing, but few of them are found, and in ordinary seasons they are not especially noticed during the early" worming" of the tobacco. In August they begin to be more abundant, and generally leave the plant about the end of the month, entering the ground, transforming to pupae and issuing as moths toward the end of September. These dates are for Virginia, but hold reasonably well as far south as Mississippi. The greatest damage done by this insect is by the August brood, when it enters the roUed-up leaves or bud of the plant. In September and October the next generation of caterpillars is found boring into the seedpod and occasionally into the flower-stem . . . The caterpillars of the last fall generation enter the ground and hib- ernate as pupse. The insect has several other food-plants aside from cotton, but its most abundant food in the South is the weed * Chloridea mrescens Fab., and C. obsoleta Fab. Family Noctuidce. t See corn ear-worms for full description and illustrations. t Farmers' Bulletin 120, U. S. Dept. Agr. The principal Insects Affect- ing the Tobacco Plant. 222 INSECT PESTS OF FARM, GARDEN AND ORCHARD known as ground cherry (Physalis viscosa).'' The Hfe history of this species is very similar, therefore, to the false budworm or bollworm. The corn ear-worm (which see) is usually found attacking tobacco in Virginia and Kentucky only late in the season after corn has commenced to harden. It then bores into the buds, seed- pods, and flower-stalks, in the same manner as the last species. In Florida, however, Pro- fessor A. L. Quaintance states that its worst in- jury is done early in the season before corn or cot- ton are available, the eggs being laid in the bud and the young larvae feed- ing on the unfolded leaves, doing very serious injury. In Florida the corn ear-worm or false budworm is more com- mon than the former species. Control. — P o i s o n e d corn-m e a 1 has been found to be a satisfactory remedy for both species when they bore into the bud. Mix a teaspoonful Fig. 187.-Larva of false budworm (Chloridea °^ arsenate of lead into a obsoleta), showing work on seed capsules of quart of finely ground tobacco plant. (After Quaintance.) cornmeal and sprinkle into the buds from a can perforated like a pepper can. This should be applied frequently, especially after heavy rains. Large buds should be opened and a pinch of the poison placed within. When spraying or dusting with an arsenical is prac- ticed against the hornworms it will aid in the control of the bud- worms, and may be advisable for them alone where injury is serious. When the injury by the false budworm occurs only INSECTS INJURIOUS TO TOBACCO 223 late in the season, it would seem that the moths might be attracted to a trap crop of late corn in the same manner as cotton is pro- tected from it. The Tobacco Leaf -miner * The larva of a small moth has become quite injurious in part, of North Carolina and Florida by mining the inside of the leafs and is thus known as the Tobacco Leaf -miner. This insect occurs in other parts of the country, but has become injurious only in the states named and in recent years. The injury is done by the larvae eating out irregular patches of the tissue in the leaves, leav- ing only the upper and lower surfaces, the lower leaves being infested the worst. The leaves are rendered unfit for wrappers, split- ting and tearing very easily on account of these blotches. A larva does not con- fine its work to one place, but makes several mines, and a single larva may thus destroy the value of a leaf for wrapping pur- poses. This migratory habit is of considerable importance, as in leaving the old and in making new mines the larvae must necessarily eat a certain amount of the surface of the leaf, and can thus be killed by an arsenical spray. The life liistory of tht? insect is not completely known, but as only about twenty days are required for all its transformations, several broods probably occur during a season. The original food-plant of this pest has been found to be the common horse or bull-nettle (Solanum carolinense), which fact further emphasizes the caution already given, to keep all weeds carefully cut down around the tobacco- field, especially those nearly related to tobacco botanically. Many planters destroy the larvae by simply crushing them with the hand, and this can be done quite rapidly, and if done before the mines become numerous should be sufficient to check the injury. * PhthorimoBa operculella Zell. Family Tineidoe. Fig. 188. — Tobacco leaf-rriner or split-worm: adult moth above; larva below at right; pupa below at left, with side view of enlarged anal segment — all enlarged (After Howard, U. S. Dept. Agr.) 224 INSECT PESTS OF FARM, GARDEN AND ORCHARD Where spraying or dusting is practised against the hornworm it should be sufficient to destroy most of the miners, as, if the leaf is thoroughly coated with poison, they would get a fatal dose in starting a new mine. The Cigarette-beetle * The most serious pest of dried tobacco is the httle brown Cigarette-beetle, which also attacks various drugs and stored food products. The beetle is but one- sixteenth inch long, of a brownish color, and with the pro-thorax bent down so that the head is obscured as if under a hood. ''Working as it does in all kinds of cured tobacco and living in this substance during all the stages of its existence," says Dr. L. 0. Howard, "it damages cigarettes and cigars principally by boring out of them, making round holes in the wrappers so that they will not draw. Leaf tobacco is injured for wrapping purposes by being punctured with holes made both by the larvae and beetles, and fillers and finecut are injured by the reduction of their substance by the actual amount consmned by the larvae." " The cigarette-beetle is practically cosmo- politan, and probably occurs in most tobacco factories in the Southern States, as well as in most wholesale drug stores. In the far South this insect multiplies rapidly through- out the greater part of the year, and its development is practically continuous in artificially warmed factories farther north." Life History. — In heated factories the in- sect may be found in all stages throughout the year. Otherwise it seems to pass the winter months in the larval state. The Fig. 189.— Work of larva is slightly larger than the beetle and (itrH™wLt"u!s: covered with hair ^ shown in Fig. 190. Dept, Agr.) When full grown it spins a compact silky * Lasioderma serricorne Fab. Family Ptinidw. INSECTS INJURIOUS TO TOBACCO 225 cocoon covered with bits of whatever it is breeding in and in it transforms to the pupa. In a, warm room the entire life cycle has been passed in forty-seven days, and it seems probable that in the District of Columbia, there are two generations a year. The life is undoubtedly intimately related to the moisture and temp- erature conditions under which it lives. Control. — When a factory or storehouse has become badly infested a thorough cleaning is the first step in the control of the pest, as tobacco fragments and dust are usually present every- e Fig. 190. — The cigarette beetle: a, larva; b, pupa; c, adult; d, side viw of adult; e, antenna — all greatly enlarged; e, still more enlarged. (After Chittenden, U. S. Dept. Agr.) where and ideal conditions for the multiplication of the pest are afforded. Infested tobacco should be opened up, if packed tightly, placed in tight boxes or in a tight room and exposed to the fumes of carbon bisulfide, using it the same as for grain insects. The quantity used will depend upon the tightness of the enclosure, the way in which the tobacco is packed, and the tem- perature. One pound to every 200 cubic feet will usually be ample. In factories where the beetle is abundant the tobacco should be steamed before use, which will kill all stages of the insect. Loose tobacco, cigars, and cigarettes, should not be left exposed to the beetles, but should be covered up or placed in tight receptacles to prevent their access. Badly infested factories and storehouses may be fumigated with hydrocyanic acid gas. Heating would be effective where practical. Several other insects are more or less serious pests of tobacco in certain parts of the country or under local conditions. The Tobacco Thrips* has caused considerable loss to growers of wrapper tobacco in Florida where it is grown under shade. * Euthrips nicotanice Hinds. Order Thysanoptera. See W. A. Hooker, Bulletin 65, and Circular 68, Bureau of Entomology, U. S. Dept. Agr. CHAPTER XIII INSECTS INJURIOUS TO COTTON * Plant-lice f With the formation of the first true leaves of cotton, winged aphids or plant-lice appear in large numbers on the under side and on the terminals, the "buds "of the plants often being black with them. Almost all of them are the common greenish Melon- aphist (see page 344), which infests melons later in the season. It is evident, therefore, that the practice of planting cotton between rows of melons is undesirable. The aphids migrate to the cotton while it is young from various common weeds upon which they have passed the winter. Another species, known as the Bur-clover Aphis § occurs on cotton at about the same time and is not readily distinguishable from the previous species, but is darker and has a shining reddish or brownish-black color. In cold weather these plant-lice often cause considerable injury to the young plants, and greatly retard their development, since they multiply very rapidly and feed mostly on the growing terminals. If there be a few warm days, however, hordes of small Hymenopterous parasites appear and in a few days often completely rid the plants of the pest. Control. — Although these aphids may be destroyed by spray- ing with kerosene emulsion, whale-oil soap, or tobacco water, as a rule the use of these on any considerable scale will hardly be profitable. Keeping the fields clear of weeds by fall and winter plowing will undoubtedly have a beneficial effect in reducing * See Hunter and Hinds, The Mexican Cotton Boll Weevil, Bulletin 51, Bureau of Entomology, U. S. Dept. Agr.; Quaintance and Brues, The Cotton Bollworm, Bulletin 50, Bureau of Entomology, U. S. Dept. Agr.; Sanderson, Miscellaneous Cotton Insects of Texas, Bulletin 57, Bureau of Entomology, Farmers' Bulletin 223, U. S. Dept. Agr. t Family Aphididce. t Aphis gossypii Glov. § Aphis medicaginis Koch. 226 Fig. 191. — The cotton worm {Alabama argillacea): young and full-grown larvae or worms, pupa, cocoons in folded leaves, and moths, at rest, and with wings expanded — three-fourths natural size. (After Comstock.) 227 228 INSECT PESTS OF FARM, GARDEN AND ORCHARD the numbers of aphids and in most cases will be the only treat- ment necessary. The corn root-aphis is also recognized as a pest of cotton, especially the young plants. When it appears it may be controlled to some extent by frequent shallow cultivation of the young plants until they are well established. Infestation may be avoided by a system of rotation where cotton does not follow either cotton or corn in infested fields.* The Cotton Worm f Until the advent of the boll weevil, the cotton worm was much the most serious insect pest of cotton. Since then, however, Fig. 192. — Pimpla conquisitor, one of the principal parasites of the cotton- caterpillar: a, larvse enlarged; b, head of same still more enlarged; c, pupa; d, adult female enlarged; e, f, end of abdomen of adult male, still more enlarged. (From Fourth Rept. U. S. Entom. Comm.) i its importance has been rather overshadowed in the mind of the planter by the onslaught of the invading Mexican pest and where the boll weevil is abundant the stripping of the late foliage by the cotton worm really aids in the control of the weevil, as will be explained later. Life History. — During the winter months the adult moth hibernates in the most southern portion of the cotton-belt, in the rank wire-grass occurring in the more thickly timbered regions. * See W. A. Thomas, S. C. Expt. Sta. Bulletin 175. ^Alabama argillacea Hubn. Family Noctuidw. See W. E. Hinds, Bul- letin 164, Alabama Agr. Expt. Station. INSECTS INJURIOUS TO COTTON 229 Only a few of these survive, but they are very capable ancestors. In early March they lay eggs upon volunteer cotton when it is only an inch or two high. The eggs are laid singly, usually upon the under surface of the leaves near the top of the plant, and about 500 are laid by each female. The egg is of a flattened convex shape, bluish-green in color, and with prominent ridges converging to the apex. In midsummer the eggs hatch in three or four days, but in spring and autumn a much longer time is required. The young larvae are a pale yellow color, but soon assume a greenish tinge, and are marked with dark spots which become more dis- tinct after the first moult, when they become marked like the full- grown caterpillars, being more or less striped with black. During the early season the greenish cater- pillars predominate, but later the black stripes become heavier and the darker forms prevail. The appetites of these caterpillars are only too well known to the cotton- grower. At first they are content with eating only the under surfaces of the leaves, occasionally pierc- Fig. 193. — Cotton-worm egg parasite (Pentar- in(T ihrnuffh Th^n ih^ ^^^'^"' ^i^^^^em); a, adult female, greatly mg tnrough. ihen the enlarged; 6, ovipositor; c, female antenna; leaves commence to look d, male antenna. (From Fourth Rept. U. S. ragged, and when they Entom. Comm.) become scarce the tender twigs and buds are attacked. When they are excessively abundant the larvae develop cannibalistic tendencies, like the boll worms, and often feed upon the weaker caterpillars. The larvae become full grown in from one to three weeks, during which time they moult some five times. When mature the caterpillar crawls into a folded leaf, which is often so eaten away that the pupa hangs exposed, and there spins around it a thin silken cocoon and transforms to the pupa, in which state the insect remains dormant for from one to four weeks, when it emerges as an adult moth. 230 INSECT PESTS OF FARM, GARDEN AND ORCHARD The moth is a dull olive-gray color with a wing expanse of about 1^ inches, which sometimes have a purplish lustre, and which are marked with darker lines as shown in Fig. 191. Like most of the owlet moths it flies only after sunset, but unlike them, it is not confined to the nectar of flowers for food, as its mouth is peculiarly adapted to piercing the skin of ripe fruit and feeding upon its juices. Injury by the cotton worm moth to ripened peaches is frequently noticed in the peach orchards of West Virginia and regions farther north. The moths are strong fliers, those of the later broods being frequently found as far north as Canada. The first two generations develop rapidly and in the extreme South the moths emerge by early April and are carried north- ward by the prevailing winds. Eggs deposited by them give rise to a brood of moths which in turn fly farther northward, and thus the worms are gradually found throughout the whole cotton belt, though with a considerable confusion between the various generations. At least seven generations occur on the Gulf Coast, and three at the northern limit of the species. Considering the number of eggs laid by each female and this number of generations, it may be readily perceived how such immense numbers of the caterpillars may arise by the latter part of the season, in a region where practically none remain over winter. If none was killed, the progeny of a single moth after four generations would amount to over 300,000,000,000 individuals, or if placed end to end, the third generation would be enough to encircle the earth at the equator over four times. Enemies. — It is thus very fortunate that there are many deadly enemies of the cotton worms, which commence their war- fare upon them with their first appearance in spring and continue it with increasing ardor throughout the season. One of the most effective of these is a minute little insect, Trichogramma pretiosa, which develops within the eggs. Mr. H. G. Hubbard once observed that in Florida from 75 to 90 per cent of the fourth brood of eggs were destroyed by this parasite, while only three or four eggs in a hundred escaped in the sixth brood. Another of the most useful parasites, Pimpla conquisitor, was noticed as early as 1847 to destroy nearly aU of the pupae of the last brood. The eggs of the Pimpla are laid upon the caterpillar, and the INSECTS INJURIOUS TO COTTON 231 maggots enter the worm and feed upon its juices. It changes to a pupa as usual, but the pupa soon dies, and large numbers are thus killed. Several similar parasites prey upon the cotton worm, and it is to be regretted that we know of no way of encourag- ing their valuable work. The common insectivorous birds eat large numbers of the worms, especially when they are scarce in early spring, and they should be protected by enacting and .enforcing most stringent laws against their wanton destruction. Control. — The most commonly used and effective remedy is to dust the plants with arsenate of lead. Dusting machines drawn by a team which will cover four rows at once are in common use. The dust may be applied with any of the powder guns, but it is most commonly appHed to two rows at once by means of bags fastened at the ends of a pole and carried by a man on horseback, who can thus dust 15 to 20 acres per day. These sacks are about 10 inches long by 4 inches in diameter, open the whole length on one side and firmly sewed at the ends. Eight-ounce Osnaburg is the best cloth for the purpose. A strip of oak or strong wood about 1/^x2 inches, and 5 feet long, has a 1-inch hole bored through it 5 inches from each end, and to this the sack is tacked, fastening one of the edges of the opening to each of the narrow sides of the pole. The sacks are filled through the holes in the pole. When freshly filled a slight jarring will shake out a sufficient amount of the poison, but when nearly empty the pole should be frequently and sharply struck with a short stick or spaces will be missed. The poison has been found most effective with- out the admixture of flour, but if it is used, lighter cloth should be used for the sacks. Besides the general use of poisons there have been several important factors which have aided in the control of the cotton worm, so that it is by no means as much of an enemy of the cotton crop as formerly. Among the most important of these, both from an entomological and general agricultural standpoint, is the diversification and rotation of crops, now coming to be more and more practiced by the progressive agriculturists of the South, This alone largely prevents the rapid spread of the pest. Since the seed has become such a valuable product of cotton, smaller varieties with many seeds and a short fibre are being grown, in contrast to the rank-growing, long-fibre sorts formerly pre- 232 INSECT PESTS OF FARM, GARDEN AND ORCHARD ferred. Thus the rows are more open, the work of the worms is more readily detected and the poison more easily applied. Other Caterpillars Injuring the FoUage Several of our common caterpillars which ordinarily feed upon various weeds frequently attack cotton foliage in restricted local- ities and do more or less serious damage. They may be readily controlled by keeping down the weeds upon which they normally feed and multiply and by dusting the foliage as for the cotton worm as soon as they are noticed upon the cotton in any numbers. Among the more common of these leaf-eating caterpillars is the Grarden Web worm* (see page 363), which may be recognized by the fine silken web which it spins over the young plants. Another is the White-lined Sphinx Caterpillar,! a yellowish- green caterpillar with black eye-spots and faint stripes, varying to blackish with yellow spots, and distinguishable from most other cotton caterpillars by the horn, characteristic of sphingid caterpillars, at the tip of the abdomen. The Salt-marsh Cater- pillarf which is one of our best-known " woolly bear" caterpil- lars, covered with black and red hairs, has frequently stripped cotton of foliage in Texas, as does the Fall Army Worm (see page 114), when it becomes locally overabundant. Many other species might be mentioned which do more or less local injury. The Cotton Square-borer § Just as the cotton squares commence to form they are often bored into by a small green caterpillar which many planters consider a stage of the bollworm and which others have called the "sharpshooter." This injury is often quite serious on a small area, as we have seen 10 per cent of the stalks entirely denuded of squares in small fields in Texas where this insect was abundant. The little caterpillars hollow out the squares in the same manner as does the bollworm, often destroying all of those on a plant knee-high and even boring into the tender stalk. The caterpillars are bright green, oval, decidedly flattened, covered with short hairs which give them a velvety appearance, and with * Loxostege similalis Guen. Family Pijralidm. t Deilephila lineata Fab. Family Sphingidoe. X Estigmene acroea Drury. Family Arctiidce. § Uranotes melinus Hbn. Family Lyccenidce, INSECTS INJURIOUS TO COTTON 233 Fig. 194. — The cotton square-borer {Uranotes melinus Hbn.): a, adult; 6, underwing of same; c, larva;d, pupa — naturalsize. (After Howard, U. S. Dept. Agr.) the head retracted under the front of the body, thus being quite unhke any stage of the bo llworm. They are the larvse of a dainty httle butterfly (Fig. 194) , of a bluish-black color, with dark reddish lustre, and with bright red spots on the posterior border of the hind wings, com- mon around cotton-fields. The small yellowish, transparent eggs are laid on the leaves and stems of cotton, cow-peas, goat- weed, and various weeds, and the larvse have also been found on hops, beans and cow-peas, seeming to prefer the latter to cotton. The eggs hatch in from two to five days, the larvae become grown in a little over two weeks, and the pupal stage averages about ten days, so that the whole life cycle re- quires about a month in Central Texas, where there are three or four generations in a season. Fortunately for the planter the large ma- jority of the caterpil- lars are parasitized, over 90 per cent of the June generation having been thus destroyed. Usually, therefore, it is hardly worth while to attempt to combat this insect, as it is not Fig. 195. — The glassy-winged sharpshooter {Ho- malodisa triquetra Fab.): adult at left, last stage of nymph at right, young nymph below — all enlarged. (Author's illustration, U. S. Dept. Agr.) 234 INSECT PESTS OF FARM, GARDEN AND ORCHARD often seriously injurious year after year. Should remedial treat- ment be necessary, thorough dusting with Paris green or arsenate of lead would probably destroy most of them, as the young cater- pillars, like the bollworms, feed to some extent upon the foliage before entering the squares. " Sharpshooters " or Leafhoppers * In late summer reports are frequent that cotton is being injured by "sharpshooters," especially on low land. These insects are reported to puncture the squares and bolls, causing them to Fig. 196. — Three cotton leafhoppers commonly called sharpshooters: a, Aulacizes irrorata; b, Oncometopia undata; c, Oncometopia lateralis — much enlarged. (Author's illustration, U. S. Dept. Agr.) drop prematurely, a small black speck showing the spot where punctured. The insect which has been most commonly credited with this work is the Glassy- winged Sharpshooter, f but with it are usually associated several near relatives with similar habits.t Few planters are able to identify the cause of the supposed injury, but many know these insects as "dodgers," from their habit of quickly dodging to the opposite side of the stem when disturbed. Ex- tensive observations and repeated experiments during two seasons * Family Jassidce. t Homalodisca triquetra Fab. X Oncometopia undata Fab., O. lateralis Fab., and Aulacizes irrorata Fab. INSECTS INJURIOUS TO COTTON 235 failed to show the slightest evidence that these insects are ever in- jurious to cotton, though they are common upon it, the supposed injury being undoubtedly due to the physiological condition of the plant which causes a shedding of the fruit at the season when the supposed injury occurs. The adult insects hibernate in rubbish on the ground near the food-plants and appear in early spring on the elm, hackberry, red- bud, Cottonwood, willow, and the tender shoots of other trees, especially on bottom-land near streams. Here they suck the juices of the tender leaves and deposit their eggs in them. The eggs are laid in rows of ten to fifteen, side by side, just under the Fig. 197. — The cotton leaf-bug {Calocoris rapidus) : a, adult ; b, c, d, stages in growth of nymph; and cotton boll, showing spots injured by cotton leaf- bug all enlarged. (Author's illustration, U. S. Dept. Agr.) surface of the leaf, forming a blister-like mark. They hatch in a few days and the young bugs, or nymphs, are grayish or yellowish in color and resemble the adults except in the lack of wings. Two or three generations occur annually in Texas, and the insects are not common on cotton until midsummer. They are exceedingly fond of banana trees, sorghum and sunflowers, sometimes doing considerable injury to the latter, but there is no evidence for con- sidering them pests of cotton. The Cotton Leaf-bug * This insect was the cause of considerable damage in Northern Texas in the latter part of the season of 1904, and had been pre- * Calocoris rapidus Say. Family Capsidce. 236 INSECT PESTS OF FARM, GARDEN AND ORCHARD viously reported as a pest of cotton, though its injury had never been general. It punctures the squares and bolls, either causing them to drop or making the bolls shrivel or decay when punctured. The feeding punctures in the bolls are indicated by small black spots, resembling diseased places, which gradually become larger and sunken, evidently due to some poisonous substance intro- duced by the beak of the insect as it sucks the juices of the boll. The bugs may be readily recognized from Fig. 197, and by the bright red spots just beyond the middle of the wing. The young are light green marked with red. Several generations of the insect occur annually, but its life history and habits are still unknown, and no means of combating it have been devised. Other Plant-bugs * Several other species of plant-bugs do considerable injury by sucking the bolls and causing them to shrink or decay. ^mi If ^ Fig. 198. — The green soldier-bug (Nezara hilaris): a, adult; h, beak; c, eggs. d, end of egg more enlarged; e, young nymph; /, last stage of nymph. (After Chittenden, U. S. Dept. Agr.) Among these are the so-called "pumpkin-bugs" or "stink-bugs," of which a large green species f is the most commonly injurious, while the blackish, leaf -footed plant-bugs, J which are more abun- dant on cucurbs, do similar injury. * See A. W. Morrill, Plant-bugs Injurious to Cotton Bolls. Bulletin 86, Bureau of Entomology, U. S. Dept. Agr. t Nezura hilaris Say. Family Pentatomidoe. X Leptoglossus oppositus Say, Family Coreidce. INSECTS INJURIOUS TO COTTON 237 " Cotton-stainer " * The cotton-stainer or red-bug is stated by Hunter to be the most important cotton pest in Florida. It occurs in small num- bers in Georgia, South Carolina and Alabama, but does practically no injury there. The principal damage is due to the bugs punctur- ing the bolls in feeding and staining the lint a brownish color. This stain seems to arise from the injured seed, at least it is most noticeable around the seed. The cocklebur seems to be the most important of the native food-plants, though the bugs feed on the night-shade and Hibiscus and sometimes attack oranges. Fig. 199. — The red bug, or cotton-stainer (Dysdercus suturellus) enlarged. a, nymph; b, adult. (From "Insect Life.") Prevention of the growth of these weeds is therefore of importance. As the bugs usually assemble in colonies, their red color may be easily observed and they may be jarred from the foliage into buckets containing water covered with a film of kerosene. In the fall and winter these insects assemble in numbers on piles of cotton seed, which may thus be used as traps and the bugs killed with kerosene or hot water. * Dysdercus suturellus H. Schf. Family Pyrrhocoridce. See W. D. Hunter, Circular 149, Bureau of Entomology, U. S. Department of Agriculture. 238 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Cotton Bollworm * One of the most destructive and widespread pests of cotton is the bollworm, the same insect as the earworm of corn already- described, which should be consulted for the life history and description. Throughout the cotton belt the moths of the third generation appear about August 1st. At that time the ears of corn have become too hard to furnish suitable food for the larvae and the moths therefore lay their eggs on the cot- ton leaves, though if any late corn is in silk it is decidedly preferred. Thus during the month of August the cotton is often seriously injured by the caterpillars bor- ing into the bolls, this injury being most seri- ous in recent years west of the Mississippi and particularly in north Texas and Louisiana. The total damage to cot- ton is estimated at upward of $40,000,000 per annum. Though more or less damage is done by the fourth generation of worms, injury is rarely serious, as the numbers are greatly reduced by parasites and unfavorable weather conditions. About two-thirds of the eggs on corn are parasitized by a tiny little insect hardly visible to the naked eye,t which be- comes so abundant late in the season as effectively to check the increase of the pest. Wasps are effective enemies of the bollworms, provisioning their nests with them. Several species of tachina-fiies parasitize * Chloridea obsoleta Fab. Family Noctuidce. See Farmers' Bulletin No. 290, U. S. Dept. Agr., by F. C. Bishop and C. R. Jones and Bulletin 50, Bureau of Entomology, U. S. Dept. Agr., by A. L. Quaintance and C. T. Brues. t Trichograinina pretiosa Riley. Fig. 200. — Bollworm at work on cotton bolls, boring into grown boll — slightly reduced. (After Quaintance and Brues, U.S. Dept. Agr.) INSECTS INJURIOUS TO COTTON 239 the caterpillars, while not a few are killed by a bacterial disease. One of the most important natural factors in reducing their num- bers, however, is their own tendency to cannibalism, the larger caterpillars attacking and destroying the weaker with a consequent marked reduction in numbers. Control. — As in protecting corn from this pest, the most effect- ive means is the plowing of the land containing the pupae in winter or late fall. Early planting of early fruiting varieties of cotton, with a liberal use of fertilizers, and frequent cultivation, so as to hasten the maturity of the crop, will result in a good crop being made before the worst injury by the boll worm occurs. These cultural measures ensure the best crops even where there are no insects to be avoided, and as an early crop is less injured by almost all cotton insects, the planter should adjust his methods to secure earliness. As the eggs are laid mostly on the cotton leaves and the little Fig. 201. — Egg of bollworm; side and top views. Highly magnified (From Quaintance andBrues, U. S. Dept. Agr.) Fig. 202. — Bollworms showing variation in color, upper larva green, middle rose, and lower, dark brown — twice natural size. (After Quaintance and Brues, U. S. Dept. Agr.) caterpillars nibble the surface before boring into the bolls, the poisoning of the foliage when the eggs are hatching will result in a very material reduction of the subsequent injury. Paris green 240 INSECT PESTS OF FARM, GARDEN AND ORCHARD has been most generally used, but recently powdered arsenate of lead has been found superior to it. Arsenate of lead is used at the rate of 2 to 5 pounds per acre, applied either pure or diluted with lime or flour, using either a bag and pole, hand powder-gun or geared dusting machine. The dusting should be done while the plants are wet with dew. When not followed immediately by rain, two applications should be sufficient, the first when the eggs commence ^^iST* '•» ^-A/t Fig. 203. — Pupa of the bollworm in its burrow in the soil, showing burrow made by the larva and filled in, and the exit burrow for the moth also made by the larva — natural size. (After Quaintance and Brues, U. S. Dept. Agr.) to hatch in numbers, usually between July 25th and August 5th, and the second about a week later. If rains follow, the applica- tions should be at once repeated. INSECTS INJURIOUS TO COTTON 241 Inasmuch as the moths prefer to lay their eggs on corn-silk, cotton may be very effectively protected by the use of strips of late corn and cow-peas, planted through the cotton so as to act as a trap crop. Leave vacant strips four or five rods wide across the fields when planting cotton. About June 1st plant these with alternate rows of Mexican June corn and cow-peas. This will bring the corn into silk about the first of August and will attract the moths to lay their eggs upon it instead of the cotton, while the cow-peas will furnish both food and shelter to the moths. Corn should never be planted with cotton when cotton is planted, for instead of acting as a trap crop it merely furnishes food upon which the worms multiply during the early season and forces those of the third generation to the cotton. The strips of corn and peas should be cut as soon as the worms on them be- come fairly grown and the land plowed to destroy any which may have pupated. " On large plantations the planting of small areas of corn here and there in the fields is prac- ticable. Such early crops as potatoes, oats, or wheat may be followed by corn and cow-peas with practically the same results." The Cotton-boll Cutworm * The larva of this species is a very common feeder upon the foliage of cotton and late in the season bores into the bolls in much the same manner as the bollworm. Cotton is but one of a long list of food-plants, however, as it is a common pest of sugar-beets, corn, wheat, cabbage, potato, asparagus, salsify, peach, raspberry, violet, cucumber, tomato, turnips, pea, rape, pigweed, cottonwood, and grasses according to Chittenden. It occurs commonly throughout the states east of the Rocky Mountains. * Prodenia ornithogalli Guen. Family Noctuidoe. See Sanderson, I.e., and F. H. Chittenden, Bulletin 27, n. s., Div. Ent., U. S. Dept. Agr., p. 64. Fig. 204. — The moth of the bollworm or corn ear- worm — enlarged one-fourth. (After Quaintance and Brues, U. S. Dept. Agr.) 242 INSECT PESTS OF FARM, GARDEN AND ORCHARD The moth has a wing expanse of about 1| inches, the fore- wings being a dark, rich, velvety brown, marked with black, yellow and ochreous as shown in the illustration, while the hind- wings are a hght gray. The grown caterpillar is 1| to ij inches long, and is quite variable in coloration, some being much darker than others, as shown in the illustration. The three whitish lines and the double row of triangular brown spots along the back of the lighter forms will easily distinguish this caterpillar from the boll worm.* Fig. 205. — The cotton-boll cutworm {Prodenia ornithogalli Guen.): dark form of male moth above; pale form, female moth below; a, pale form of larva; b, dark form of larva; c, lateral view of abdominal segments of pale form; d, same of dark form. (After Chittenden, U. S. Dept. Agr.) Life History. — The life history has not been carefully observed in the North, but from observations made by the writer in Texas the life history in the Gulf States seems to be as follows: The winter is usually passed in the pupal stage in the soil, though possibly a few moths, emerging late, hibernate. The first brood of moths appears from the middle of May until the middle of June, mostly early in June. A second brood appears during the latter half of July, and a third late in August and dur- ing September. A few of the fourth brood may emerge in Decem- ber, but most of them do not do so until the very early spring, when they lay eggs upon various weeds on which the larvse feed * See Chittenden, I.e., p. 36, for distinguishing characters of related species of Prodenia. INSECTS INJURIOUS TO COTTON 243 until cotton appears. The length of time occupied in the dif- ferent stages is seen to be quite variable, but is approximately six days for the egg, twenty days for the larva, and thirteen days (usually ten to fifteen days) for the pupa — making a total of about forty days for the complete life cycle. Dr. Chittenden believes that there are two generations in the North and probably three in the latitude of the District of Cohunbia. Control. — This species has not been sufficiently injurious on cotton to warrant extensive experiments in its control. Where it attacks young plants of cotton or other crops, it may be com- bated with the means suggested for other cutworms. Where it becomes injurious to the bolls, it might be controlled by thorough dusting or spraying with arsenicals, which would destroy the young larvae while they are still feeding on the foliage. The Mexican Cotton Boll Weevil * Not since the invasion of the Mississippi Valley by the Rocky Mountain locusts in the 70's has any insect caused such ruin I" 1 Fig. 206. — The cotton boll weevil, natural size, showing variation in size and color. to any staple crop as has the boll weevil in the territory affected during the past twenty years, and it is one of the factors in the recent high prices of cotton. Like several of the worst insect pests of the South it is a native of Central America and came to us from Mexico, crossing the Rio Grande at Brownsville, Texas, about 1890. As early as 1862 the weevil caused the growers at Monclova, Mexico, to abandon cotton culture and when they again planted it in 1893, the beetle promptly appeared and destroyed the entire crop. It multiplied * Anlhondmus grandis Boh. Family Curculionidce. See W. D. Hunter. "The Boll Weevil Problem," Farmers' Bulletin 848, U. S. Dept. Agr.; and Hunter and Hinds, Bulletin 51, Bureau of Entomology, U. S. Dept. Agr. 244 INSECT PESTS OF FARM, GARDEN AND ORCHARD rapidly in south Texas, ruining the crops, and by 1895 had spread northward to a line extending eastward from San Antonio. Since then it has spread northward and eastward, about sixty miles a year, until in 1905 it had covered all of Texas and western Louisiana and is now found almost throughout the cotton area where weather conditions permit. In 1904, after an exhaustive study of all available data, the writer estimated the loss in Texas alone at $25,000,000, and that the pest had then cost the State $100,000,000. Owing to decrease in acreage and the gen- eral use of methods for preventing or avoiding injury, the injury has not increased proportion- ately to the spread of the pest, but the total annual loss is at least as much as in 1904, though no accurate estimates have been recently made for the whole ter- FiG. 207.— The cotton boll weevil— ritory affected enlarged. 2.^/e History.— The parent in- sect is a small brownish beetle about one-quarter inch long, varying from one-eighth to one-third, including the snout, which is about half as long as the body. Recently emerged weevils are light yellowish in color, but they soon become grayish- brown and later almost blackish. There are many nearly related weevils which very closely resemble the boll weevil, and only an entomoligist can identify the species with certainty, but the two teeth at the tip of the femora of the fore-legs (Fig. 207), are the most characteristic structure by which it may be distinguished. The boll weevil feeds only upon cotton, and weevils found feeding on other plants are certainly of other species. However, there has recently been discovered in Arizona an insect which very closely resembles the boll weevil and which has been classed by authorities as merely a geographical variety of the true boll weevil and named Anthonomus grandis thurberiae, the Arizona wild cotton weevil, which feeds on a wild cotton {Thurberia thespesioides) found growing in that region. This 245 246 INSECT PESTS OF FARM, GARDEN AND ORCHARD would make it seem probable that the true boll weevil might feed on the wild cotton plant as well as on the true cotton. The weevils commence to emerge from hibernation soon after cotton is up and continue to emerge until the cotton commences to square freely. During the spring the beetles feed on the foliage, partic- ularly in the tender terminals, and as soon as squares are formed the females commence to lay their eggs in them. Each female lays an average of about 140 eggs, lay- FiG. 209.— Cotton square with bracts i^g four or five a day. The female opened to show weevil at work on 7 •' the bud, which shows a feeding drills a small cavity in the square puncture. ^^-^^-j -^^ -^ deposits a small oval white egg, which hatches in about three days. The grub feeds upon the embryo flower, which usually fails to develop, and the Fig. 210. — The cotton boll weevil; eggs among the anthers at points indi- cated by arrows, the cross-section at the right showing opening through which egg was deposited — greatly enlarged. infested square generally falls to the ground. In from seven to twelve days the larva is full grown and changes to the pupa, INSECTS INJURIOUS TO COTTON 247 which stage lasts from three to five days. Thus from egg to adult requires from two to three weeks, though cHmatic conditions cause considerable variation in the length of time. The larva is a footless, white grub, with brown head, which lies curled up in the square as shown in Fig. 211, where the soft white pupa is also found. The adult weevils feed en- tirely during the day. Their length of life depends upon various conditions, but in the summer season the maj- ority do not live over sixty 1^^10.211. — The cotton boll weevil, larva and days, while during the cooler part of the year those which hibernate live five or six months. Many squares are destroyed by the feeding punctures of the weevils. ''The males feed upon the squares and bolls without moving until the food begins to deteriorate. The females refi'ain from ovipositing in squares visited by other fe- males. This applies through- out most of the season, but late in the fall, when all the fruit has become infested, several eggs may be placed in a single square or boll. As many as fifteen larvae have been found in a boll. The squares are greatly preferred as food and as p 1 a c e s for de- positing eggs. As long as a supply of squares is present the bolls are not damaged to any serious extent. The bolls, therefore, have a fair chance ^°ho'J4-S?SlTe^/;;?'lStr."S;> to <1«™10P <^ long - squares enlarged. are being formed. When- r ' i^ jm ^ j^^ '^m ^&jip jpiBP ^!*s k_,"^ , 1 _,_ 248 INSECT PESTS OF FARM, GARDEN AND ORCHARD ever frost or other unfavorable weather causes the plants to cease putting on squares, the weevils attack the bolls. A conservative estimate of the possible progeny of a single pair of weevils during a season beginning on June 20, and extending to November 4, is 12,755,100." — Hunter. Although the weevil may develop from egg to adult in two or three weeks, it requires an average of about forty-three days for a complete generation and there are probably not over four or five generations in a season With the first killing frosts, most of the immature stages developing are killed, though in south Texas they often develop during the winter, and the adult weevils soon go into hibernation. When seeking places for hiber- nation the weevils migrate from field to field, and it is at this season that the principal migra- tion of the pest takes place. The weevils may hibernate in hedges, woods, corn-fields, haystacks, or farm buildings, particularly about seed-houses or similar sit- uations. Experiments have shown that Spanish moss forms an exceedingly favorable place for hibernation, and that many weevils pass the winter in it on trees some distance above the ground. Others may hiber- nate in the cotton-field, crawling into cracks, under grass, weeds, and trash, and in the empty cotton burrs, while in the more southern sections many hibernate in injured bolls. The weevils which hibernate most successfully do so outside of the cotton fields. The number which survive the winter has been accurately determined under various conditions for several seasons, and depends upon the minimum temperature, the amount of moist- ure, and the kind of shelter. Thus in central Texas but 2 or 3 per cent survive in many normal winters, while in the open winter of 1906-07 11.5 per cent survived; in South Texas 15 per cent may survive, and in experiments made in Central Louisiana in 1908-09 with rather favorable conditions 20 per cent survived. The Fig. 213. — Cotton boll weevils hiber- nating in locks of cotton removed from old bolls left on stalks over winter. INSECTS INJURIOUS TO COTTON 24d importance of reducing the number which survive the winter is evident. Natural Control.- — If infested squares fall to the ground and lie on the unshaded, hot soil the larvae or pupae within them are soon killed. As many as 40 per cent of the immature stages have thus been found dead in many fields. The importance of wide rows and varieties which produce little shade is therefore apparent, and it is evident that injury will be much less on dry upland soil, and much more severe in bottoms where the cotton grows rank and thick. Over a score of parasites* prey upon the immature stages within the squares or bolls, and they seem to be increasing in num- bers and effectiveness as they become adapted to living upon the weevil, as they are all native insects which prey upon nearly Fig. 214. — Chain cultivator for use in drawing weevil infested squares to center of row. (After Hunter, U. S. Dept. Agr.) related species of weevils and other insects. As many as two-thirds of the immature stages have been destroyed by them in certain fields, though ordinarily not ever 5 per cent of the total are para- sitized. Several species of ants also feed on the immature stages, 20 to 30 per cent of those in fallen squares and bolls often being destroyed by them. The ants destroy many more in the fallen squares than in those hanging on the plants, so that the dropping of the squares aids their good work as well as exposes the squares to the heat ot the sun. * See W . D Pierce, Studies of Parasites on the Cotton Boll Weevil, Bulletin 73, Buieau ot Entomology, U. S Dept Agr. 250 INSECT PESTS OF FARM, GARDEN AND ORCHARD Usually about 70 per cent of the infested squares drop, and in these 70 to 80 per cent of the immature stages are destroyed by natural causes.* Control. — By far the most important measure in the control of the boll weevil is the destruction of the plants in the fall as soon as the cotton can be picked. This both detroys the weevils and pre- vents their increase. The stalks should be plowed out and burned as soon as possible. It is well to plow out all but a row here and there upon which the weevils will concen- trate, then as soon as the piles are dry enough to burn, cut the remain- ing rows and burn at once. In this way the great bulk of the adult weevils and all of the immature stages in the squares and bolls are des- _ „^^ „, troyed. The few escaping weevils will Fig. 215. — oolenopsis gemmata , . i . i ,• ,i ,i Fab., a native ant which is a be starved out before the weather valuable enemy of the boll becomes cold enough for them to weevil — much enlarged. . (After Hunter and Hinds, U. hibernate, or will be so weakened as S. Dept. Agr.) ^o die in "hibernation. Thus it has been shown by Professor Wilmon Newell, in Louisiana, that where the weevils were forced into hibernation on October 15th only 3 per cent survived the winter, but that when the destruction of the stalks was put off until after December 15th, 43 percent sur- vived, with proportional numbers at intervening dates. Further- more, the development of the late broods which furnish the majority of the weevils which hibernate is effectively prevented. The re- moval of the plants also facilitates winter plowing, which aids in pro- ducing an early crop the next year. Many experiments and the experience of practical planters have shown that the destruction of the stalks in the fall is of primary importance in the control of the weevil, particularly upon bottom lands. Experiments made in Calhoun County, Texas, where the stalks were destroyed on 410 * See W. E. Hinds, Some Factors in the Natural Control of the Mexican Cotton Boll Weevil, Bulletin 74, Bureau of Entomology, U. S. Dept. Agr. INSECTS INJURIOUS TO COTTON 251 acres, showed an increase the next season of over one-quarter bale per acre as compared with fields where the stalks had been left standing, the benefit being worth $14.56 per acre, or over twenty-nine times the cost of the work. It is better to plow out the stalks than to cut them, particularly in the far South, as the stalks will frequently sprout out in the late fall and thus furnish food for the late weevils, or will sprout in early spring and furnish food for those first emerging from hibernation. For the same reasons all volunteer cotton should be destroyed. It is evident that the thorough defoliation of the plants by the cotton leafworm will secure much the same result as the destruc- tion of the stalks, by removing the food supply of the weevil. Planters should not poison the leaf worms, therefore, when they appear during the lat- ter part of the season in fields injured by the weevil, for though formerly much dreaded they are now a great aid in pre- venting the increase of the weevil in fall. It has been demon- strated that injury by the weevil is never so severe where cotton is planted after some other crop, this being due to the fact that the weevils do not fly far from their hibernating quarters in the spring. By hastening the maturity of the crop, injury by the weevils may be avoided by making the crop before they have become most abundant. Everything possible should therefore be done toward hastening maturity, and this will be of importance in rela- tion to the early destruction of the stalks in the fall. Land should be plowed in the winter and a good seed bed prepared. Cotton Fig. 216. — Bracon mellitor Say, one of the most im- portant parasites of the boll weevil larvfe — much enlarged. (After Hunter and Hinds, U. S. Dept. Agr.) 252 INSECT PESTS OF FARM, GARDEN AND ORCHARD should be planted as early as possible with safety. A liberal use of commercial fertilizers will hasten the growth of the crop even on fairly fertile soils, and on poor soils their use will return a hand- some profit. Early varieties of cotton should be planted, among the most satisfactory being, Rowden, Triumph, Cleveland Big Boll, Cook's Improved, King, Hawkins' Early Prolific, and Sim- kins. Seed should be secured from the originators of the varie- ties as far as possible. Chop out the plants as soon as possible. Frequent light cultivation will be found of the greatest importance in hastening the crop. Deep cultivation and cultivating close to the plants should be avoided as causing the squares to shed, and the old practice of " laying by " by running a broad sweep down the middles should be avoided. The lightest possible cultivation to keep the surface soil stirred is the best. All of these methods which aid in hastening the maturity of the crop are commonly called " cultural methods " of preventing loss from the weevil. They are not directed againts the weevil itself, but are merely the best agricultural methods for securing an early crop, and on light upland soils attention to these methods will alone be sufficient to secure a good crop. It has already been shown that the immature stages in squares falling on the hot soil will be killed by the heat. To aid in this the rows should be planted fairly wide apart, and varieties pro- ducing a minimum of shade are preferable as are those which readily shed their squares when injured. As most of the squares drop beneath the plants where they are shaded, any means of scraping them into the centers of the rows will aid in their de- struction. For this purpose a chain cultivator as described by Hunter (I.e.) (Fig. 215) has proven very efficient for this purpose. The chains may be attached to ordinary cultivators by special attachments. During 1909 Professor Wilmon Newell and his assistants demonstrated at several places in Louisiana that the weevil may be successfully poisoned by the use of dry or powdered arsenate of lead, though previous experiments with dry Paris green and arsenate of lead as a liquid spray had not proven of practical value for various reasons. An increase of 71 per cent of the crop was secured on considerable areas and the results were duplicated by practical planters. Professor Newell recommends that the INSECTS INJURIOUS TO COTTON 253 poison be applied first when the first squares appear and that five applications be given at weekly intervals. The poison must be applied by hand with a powder-gun so that it is blown into the squares. The first application requires about 2| pounds per acre and the last 5 to 7 pounds. Since that time there has been a very considerable amount of experimental work on boll weevil poisoning and opinions as to the value of the treatment have been variable. All authorities seem now to agree that poisoning with arsenate of lead or of calcium, applied in the form of a dust, is a valuable means of protection from the weevil, somewhat more favorable results having been secured from the arsenate of lead than from the calcium arsenate. The number of treatments and the amount of material used will vary somewhat with the infesta- tion and local conditions but eight pounds per acre has been used with profit. Professor Newell puts special-emphasis on applying the material so that it will cover the squares, bolls and terminal buds rather than the foliage.* The Pink Bollworm f An insect which might become of the greatest importance to the cotton industry is the pink bollworm, now present in this country in only small areas in p^,^, Texas and Louisiana and being eradicated in that area by vigor- ous measures prosecuted by the Bureau of Entomology of the United States Department of Agri- culture, which also maintains a strict quarantine to prevent the spread, even prohibiting the grow- ing of cotton in certain counties in order to form a barrier to prog- ress by creating a belt where no food can be secured by the insect. Fig. 217.— The pink bollworm {Pec- The pink bollworm is probably ^X^i '(SticM^' a native of southern Asia and Research, Vol. IX, No. 10.) * See Newell and Smith, Circular 33, La. Crop Pest Comm., ad Newell and Bynum, Jour. Ec. Ent., Vol. 13, No. 1, 1920; also B. R. Coad, U. S. Dept. Agr., Bulletin 731. t Pectinophora gossypiella Saunders. Family Gelechiidce. See W. D. Hun- ter, Bulletin 723, U. S. Dept. of Agr. 254 INSECT PESTS OF FARM, GARDEN AND ORCHARD is found in various parts of Asia and Africa and in Hawaii, Brazil and Mexico, having been introduced from the latter country into Texas. The adult is a small moth of brownish color and with narrow, fringed wings. The wing expanse is never as great as one inch. piY°'™>™> PUTE n The larva is a small, smooth, '^^^^^^^(^^f^^^^^^f^&jf^^ pinkish caterpillar with i^^^^^^^^^^^^^^y^^^k eight pairs of legs and pro- ^^^^"^^ ^^•^^^•0^^'^^'^='^^'='^^^ jggg^ being in this respect very unlike the boll weevil Fig. 218 — The pink bollworm: outline , u- u • a ^+i^oc, t+ drawing of larva, showing structure; ^^rva which IS footless. It much enlarged. (After Busck, Jour. Agr. feeds entirely within the Research, Vol. IX, No. 10.) ^o^g ^nd even in the seeds of cotton and it is in the seeds that it is most likely to be carried from place to place. Since it is in the process of extermination it is not necessary to do more here than to call attention to the seriousness of the insect and to repeat the warnings to cotton growers to report promptly to the Federal or State authorities the presence of any insect which might possibly be the pink bollworm. The Red Spider * The so-called red spider is a very minute reddish mite which attacks a great variety of cultivated plants and is frequently injurious, often being mistaken for a fungous disease and called a rust. They pass the winter mainly as adults and they breed continuously throughout the growing season of plants, migrating from plant to plant in search of food. They are found over most of the eastern part of the country and on the Pacific coast but are much more abundant in the cotton growing regions than elsewhere. Leaves of badly infested plants turn yellow, wilt, droop and finally fall off. Control measures recommended as summarized by McGregor and McDonough, 1. c, are: " To prevent injury to cotton by red spiders the following steps should be taken: (1) Destruction of all weeds around the * Tetranychus telarius Linn. Family Tetranychidae. Order Acarina. See McGregor and McDonough, Bulletin 416, U. S. Dept. of Agr. INSECTS INJURIOUS TO COTTON 255 farm during the winter and early spring; (2) spraying of culti- vated plants around the dwelHngs with a contact insecticide; (3) maintaining a finely pulverized surface soil; (4) destruction of early infested plants on large areas of heavy infestation by plowing up and burning; and finally, if the infestation is more Fig. 219. — The common red spider {Tetranychus telarius): 1, the egg; 2, the newly vhatched larva; S, the recently molted protonymph; 4, the mature deutonymph just prior to the final molt; 5, the adult female. Highly magnified. (After McGregor and McDonough, Bull. 416, U. S. Dept. of Agr.) or less general, (5) spraying the cotton plants with one of the following contact insecticides: Potassium sulphide, lime-sulfur, kerosene emulsion, or a flour-paste solution." CHAPTER XIV INSECTS INJURIOUS TO POTATOES AND TOMATOES The Potato Stalk-borer * In some sections this insect has rivaled the famous Colorado potato-bug in the damage it has inflicted upon potato-vines. It Fig. 220. — Work of potato stalk-borer in potato-vines. (After J. B. Smith.) was recorded as badly damaging the crop in Iowa in 1890, and was found by Dr. Riley in Missouri as early as 1869. The beetles were first noted in New Jersey in 1895, and have been injurious in Maryland and most of the Middle States. Life History. — The grubs, which bore into the stalks of the vines, ate the larvae of some small ashen-gray beetles which appear early * Trichobaris trinotata Say. Family Curculionidce. 256 INSECTS INJURIOUS TO POTATOES AND TOMATOES 257 in spring and into June. These beetles are about one-fourth of an inch long, with a long, black beak or snout, and are marked at the base of the wing-covers by three black spots which give the insect its specific name, trinotata. Each beetle punctures a small hole in the base of a stem by means of its beak, hollows out a small cavity, and there lays a single small, oval, whitish egg. From these eggs some small, white grubs with brown heads hatch in a few days and commence to bore into the stalk. ■ These gru-bs keep eating, either in the main stalk or branches, from August 1st to September 1st, when they have become full grown. At this time the grubs are about one-half an inch long, of a dirty white or yellowish color. Fig. 221. -Potato stalk-borer (Trichobaris trinotata). Larva, pupa and adult. (After J. B. Smith.) with a yellowish-brown, horny head, and without legs. About the middle of August, as a general rule, the grubs construct small, oval cocoons of chips and fibres in the stalk of the vine near the sur- face of the soil, and there transform to the pupae. During late August and September the mature beetles shed the pupal skins, in which they have remained dormant for the last few weeks, but remain in the vines during the winter, and do not come forth till the following spring. Remedies. — On account of its internal feeding habits no poison can be successfully used against this pest, and the only remedy, but a good one, is to rake up the vines and burn them as soon as the potatoes have ^een dug. As this insect also feeds upon the Jamestown weed, horse-nettle, and other weeds of the Nightshade family, or Solanacece, these should be cut down very closely. 258 INSECT PESTS OF FARM, GARDEN AND ORCHARD When the grubs are noticed in the plants, a good allowance of fer- tilizer will do much to quicken growth and thus enable them to mature a crop. The Potato Tuber-worm * The most serious pest of the potato in California is the Tuber- worm, which in tobacco regions of the Southern States is known as the " split worm " or leaf -miner (see page 223). Not infre- quently 25 per cent of the crop is lost in infested regions in California, injury occurring both in the fields and to the tubers in storage. As the pest is carried in the potatoes and breeds in storage throughout the warm winters of California, and when exported across the Pacific, it is necessary to inspect closely potatoes from infested regions. Although no injury to potatoes has occurred outside of California, and though the insect probably could not exist in the North, it may well be guarded against in the Southern States, where it is a common tobacco pest.f Moths which have developed from larvsB working in stored potatoes are on the wing when young potatoes are up, and lay their eggs at the base of the leaves. The young larvse bore into the stalks, often causing the plants to wilt and die. On older plants or when the stalks harden, the larvsG leave the stalks and enter the tubers, particularly where they may be exposed. Where potatoes are exposed by being insufficiently covered the moths will lay their eggs directly upon them, as they also do upon po- tatoes exposed in the field after digging. Most of the observations upon the life history seem to have been made upon the insect when breeding in stored potatoes. The eggs are about one-fiftieth inch long, oval, white, and laid singly or in pairs, about the eyes of the potatoes, or in similar rough places, where they are seen with difficulty. They hatch in a week or ten days, and the young larvsB are about one-twenty- fifth inch long of a transparent white color. The larvae burrow beneath the skin and bore into the potatoes, filling theu' burrows with grass and excrement, which soon give rise to various rots which cause the destruction of the tuber, already rendered imfit for food by the burrows. The larvse become full grown * Phthorimcea opercidella Zell. See W. T. Clarke, Bulletin 135, California Agr. Exp. Sta. Also J. E. Graf Bulletin 427, U. S. Dept. of Agr, t Recently serious injury by this insect has been reported to potatoes near Hallettsville, Texas. INSECTS INJURIOUS TO POTATOES AND TOMATOES 259 in about six or seven weeks. They are then about a half inch long. The head is dark brown; the first segment is an old rose color, with dark brown shield on the back; the second segment is a similar clouded pink; while the third and succeeding segments are a clouded white, often becoming yellowish or green- ish, according to the food eaten. The full-grown larva re- turns to the mouth of the burrow and there makes its cocoon, or leaves it and forms the cocoon in some depression of the potato or in some crack of the storage vessel or in a fold of the bag. The cocoon is constructed quite differently from that of most moths, as described by Mr. Clarke. The larva first makes a mat of silk and then forms an outer layer to the surface of which particles of dirt and rubbish adhere so that the cocoon is well concealed. When this pocket-like cocoon is finished the larva enters it and closes the open end and in it transforms to the pupa. The pupal stage lasts about two weeks, so that the complete life cycle requires from nine to twelve weeks, there being several generations during the year, according to the temperature. Control. — As the insect breeds on various common weeds of the Nightshade family {Solanacece) , it is important that they be destroyed wherever found. Seed potatoes must be free from the larvae, or they will soon give rise to moths which will infest a whole field. When young plants are found wilting, the infested stalks should be cut and destroyed as soon as possible to prevent the further development and spread of the pest. Care should be taken in cultivating to hill up the soil, or thoroughly cover the tubers, so that they are not exposed. After digging, the potatoes should not be left exposed in the field any longer than is absolutely necessary and should not be covered with the tops to shade them, as is often done, as this furnishes a shelter for the moths and induces oviposition upon the tubers. Infested fields should have the stalks and all rubbish and refuse thoroughly raked up and bm'ned as soon as possible, or sheep and hogs may be turned into the fields to destroy the stages which may be left in the vines or in the soil. Where fields have been flooded for two or three weeks after the crop has been dug, they have been entirely freed of the pest. For the treatment of stored potatoes, fumigation with carbon bisulfide in a tight room seems to be the only satisfactory method. This should be done 260 INSECT PESTS OF FARM, GARDEN AND ORCHARD as described for grain insects (see page 187). The tubers should be fumigated as soon as stored, and the treatment should be repeated at intervals of two weeks, four or five fumigations being recommended to free the potatoes entirely of all stages. Obviously it will be important to sort over infested tubers and remove all which are materially injured to prevent the increase of rot in others. Colorado Potato-beetle * First and foremost among the enemies of the potato-grower stands the Colorado potato-beetle — the insect which in the early seventies, on account of our ignorance of it, was made an entomo- FiG. 222. — The Colorado potato-beetle (Leptinotarsa decemlineata Say.): a, eggs; h, larva; c, pupa; d, beetle; e, elytra or wing-cover of beetle; /, leg of beetle. (After Riley.) logical bugbear. But "there's no great loss without some small gain," and we may be thankful that the invasion of this beetle also brought about the use of Paris green, an insecticide which has since saved millions upon millions of dollars to the American farmer. Thus, with an effectual remedy which is nov/ used where this pest occurs as regularly as potatoes are planted, " familiarity has bred contempt," and to-day we have but little fear of its attack. * Leptinotarsa decemlineata Say. Family Chrysomelidoe. See F. H. Chit- tenden, Circular 87, Bureau of Entomology, U. S. Agr. Dept. INSECTS INJURIOUS TO POTATOES AND TOMATOES 261 History. — As is probably known to most of the older genera- tion who watched its spread eastward, the Colorado potato-beetle, as its name indicates, was a native of the Rocky Mountain region, and until about 1855 was satisfied with feeding upon various com- mon weeds of the same genus as the potato-plant, principally Solanum datura, and closely allied genera. But with the settle- ment of this country and the introduction of the Irish potato, these bugs also began to take advantage of the fruits of civilization and transferred their feeding-grounds from the roadside to the potato-patch, and rapidly spread eastward from one to another, as well as being transported in the shipping of the potatoes. Thus, in 1859 they had reached a point one hundred miles west of Omaha, Neb. ; five years later they crossed the Mississippi into Illinois; and they advanced steadily eastward till recorded in the Atlantic States in 1874. Though slow to be introduced into some few sections of the country, it is safe to assert that this pest may to-day be found almost wherever the potato is grown in the United States or southern Canada. Life History. — During October- the beetles enter the earth and there hibernate till the warm sunshine of April or May brings them forth. As soon as the young plants appear, the female beetles deposit their yellow eggs upon the underside of the leaves near the tips, each female laying an average of about five hundred eggs during the course of a month. Meanwhile the beetles have done considerable damage by eating the young and tender plants. In about a week there hatch a horde of very small but very hungry larvse, which fairly gorge themselves with potato-foliage and increase in size with astonishing rapidity. In two and a half to three weeks, after having eaten an amount of food out of « ^ \q all proportion to their size, the larvae become yig. 223. a, beakof pre- fuU grown, and enter the earth, where they daceous bug; h, Podi- . ^, 1 11 ^ , s- ^ *"s spinosus Dall.; c, lorm smooth, oval cells, and transform to beak of plant-feeding pupae. In a week or two the adult beetles bug. - (After Riley.) emerge from the pupal skins and after feeding for a couple of weeks, deposit eggs for a second generation, which develops in the same way, and the beetles from which hibernate as already described. Throughout the territory where the beetles are most in- 262 INSECT PESTS OF FARM, GARDEN AND ORCHARD jurious there are two generations a year, but further south there is evidence of at least a partial, if not complete, third generation, and in the northern range of the species there is but one gen- eration a year. Natural Enemies. — One of the chief agencies to prevent the excessive multiplication of this pest is the weather. Thus, Pro-. fessor Otto Lugger records that in Minnesota, late in the fall of 1894, the beetles were lured from their winter quarters by a few warm days, and most of them subsequently perished from hunger or frost. In addition to this during the late summer of 1894 there was an excessive drouth, so that but few of the second brood matured. Thus in 1895 there were very few of the in- sects to be seen. Among the birds, the common crow, the red-breasted gros- beak, and turkeys often feed upon this pest to a considerable extent. Probably the most destructive insect-parasite of the larvae is a Tachinid-fly known to science as Lydella doryphoroe Riley, which rather closely resembles the com- mon house fly, both in size and color. A single egg is laid on a potato bug and from it hatches a small, footless maggot which bur- rows inside the bug. When the larva enters the earth, the effect of the maggot's work becomes ap- parent, and instead of transform- _ , . . , , ^ , ing to a pupa and beetle, it shrivels Fig. 224.— Tachinid parasite of Col- , ,. , , . ,- orado potato-beetle {Lydella dory- up and dies; but the maggot itself phorce Ril.). (After Riley.) contracts into a hard, brown pupa, £rom which the fly eventually emerges. Thus in 1868, when first noted by Dr. C. V. Riley, he asserted that in Missouri fully 10 per cent of the second brood and one-half of the third were destroyed by this parasite. Many of our common lady-bird beetles and their larvae check the pest by feeding upon the eggs. Several predaceous bugs, par- ticularly the spined soldier-bug {Podisus spinosus Dall.) (Fig. 223) are of value in destroying the larvae, into which they thrust their short, powerful beaks, and then suck out the juices of the body, ■*, «W^Vu" ' ■ ^-=-'-. :^ I5*SfRfia&5«^!ffliKai«3j' . J Fici. 225. — - Fioldspniyer, with modifications, adapted for pot.ato spray- ing by L. C. Corbett, operating at the Virginia Truck Experiment Station, Norfolk, Va. 263 264 INSECT PESTS OF FARM, GARDEN AND ORCHARD leaving an empty skin. One or two of these closely resemble the common squash-bug (Anasa, tristis De G.), but are really very dissimilar, and whereas the beaks of the predaceous forms are short and thick as in Fig. 223, a, those, of plant-feeders, like the squash-bug, are long and slender, as in Fig. 223, b. Several species of ground -beetles are often found preying upon the larvae and beetles, but, unlike the bugs, attack them by means Fig. 226.— Murky ground-beetle (Harpalus caliginosus) : a, its larva; b, head of larva showing mouthparts. (After Riley.) of their powerful biting jaws. These beetles are also exceedingly beneficial in feeding upon many other injurious insects, and are among the farmers' best insect friends (Fig. 227). Remedies. — As an artificial remedy for this pest, Paris green has long been proven to be both effectual and practical. For small areas it may be used dry by mixing it with fifty times its weight of dry flour, land- plaster, or air-slaked lime, and should be applied while the plants are still wet with dew, either by a perforated can, or, better, by one of the „„ _, , , . improved powder-guns by Fig. 227. — rower sprayer adapted for r- i • i <• spraying several rows of plan,ts at one means ot which two rows of time. Courtesy the Bean Spray Pump Co. plants may be powdered at once. On larger areas spraying will be found more satisfactory. One pound of Paris green and 1 pound of freshly slaked quick- lime to 50 gallons of water will kill all the larvae, but often 2 to 3 pounds are necessary to destroy the beetles. Eotato eetle or slu^ POTATO BEETLE ARSENATE OF LEAD OR OTHER ARSENICAL Use arsenate of lead in proportion of 2 pounds cf i powdered form(or4 lbs of pastejto 50 g'allonsof vvater.Mix first with small quantity of water and then stir thoroughly into the full amount. If arseaite of zinc or arsenate of lime is used follow^ directions on package. Apply with a good pump throwing a fine mist. Cover the foliaje completely: Be?in spraying •when the beetles first appear Spray for the slugs when the eggs are hatching an.d repeat as often as necessary. I. .' ' '"'Til' ' ' ■-'f' ;/ Infall beetles reenter fround to spend winter. In iprins the/' '/ emci^e to fepd on the young plants. Then the females la/ theirejjs ■ 7 onuncJer sides of leaves, which produce first sencration of rluSs.//'^ Fig. 228. — Bureau of Entomology, U. S. Department of Agriculture, popular poster on the potato-beetle. 265 266 INSECT PESTS OF FARM, GARDEN AND ORCHARD. Many growers now prefer to use arsenate of lead at from 3 to 5 pounds to the barrel, as there is no danger of burning the foliage with it, and it is much more adhesive. Where Bordeaux mixture is not used the arsenate of lead is much preferable on account of its superior adhesiveness. Where Bordeaux mixture is used, arsenite of lime, or arsenite of lime made with soda, may be used, but these homemade arsenicals should not be used alone, on account of their burning the foliage. The vines should be sprayed first when they are a few inches high, and the spraying repeated once or twice at intervals of ten days or two weeks. The larvae are so easily killed by arsenicals that potato growers no longer fear their work, but large quantities Fig. 229. — The convergent ladybird {Hippodamia convergens): a, adult; b pupa; c, larva; enlarged. (After Chittenden, U. S. Dept. Agr.) of Paris green are wasted by careless application, and by dusting unduly large amounts with poor apparatus, which not infrequently results in burning the foliage. For small areas a bucket or knap- sack pump will be found satisfactory, but for over an acre a barrel pump with a row attachment will prove more economical, and for over ten acres a geared machine spraying several rows at once will be needed. Cleaning up the vines and plowing potato land in the fall after the crop has been harvested will aid in reducing the num- bers of the hibernating beetles. Flea-beetles * While the potatoes and tomatoes are but a few inches high they are often attacked by myriads of small black beetles, which from * Family Chrysomelidce. INSECTS INJURIOUS TO POTATOES AND TOMATOES 267 their power of making long quick jumps are known as flea-beetles. They soon riddle the foliage, often so badly that the plants wilt, and replanting is necessary, particularly with tomatoes. Several species are known to attack the potato, the two most common being the potato or cucumber flea-beetle (Epitrix cucum- eris Harris) and one which Professor H. A. Garman has styled the Southern Potato Flea-beetle {Epitrix fuscula). The Tobacco Flea- beetle (Epitrix parvula) is not uncommonly found on the vines in sections where tobacco is also grown, and other species do similar injury in other sections. All of these species are, however, essen- tially the same in habits and life history, and the same remedies apply to all. The potato flea-beetle* is the most destructive. It is only one-sixteenth inch long, jet black, except the yellowish antennae a b Fig. 230. — a, potato flea^beetle; h, egg-plant flea-beetle, both greatly en- larged. (After Chittenden, U. S. Dept. Agr.) and legs, and there is a deep groove across the base of the thorax (Fig. 230, a). It seems to occur throughout the United States, but is more commonly injurious in the North. Eggplant and tobacco, as well as numerous garden vegetables are similarly injured. This species has commonly been called the cucumber flea- beetle from its specific name, but it is evidently a misnomer, as it is much more abundant upon the potato and related plants. During the winter the beetles hibernate under leaves, rubbish, etc., and in the spring come forth and lay their eggs upon the roots of some of our common weeds of the Nightshade family, such as the horse-nettle, Jamestown-weed, Desmodium, etc., * Epitrix cucumeris Harris. See O. A. Johannsen, Bulletin 211, Maine Agr. Expt. Sta. 268 INSECT PESTS OF FARM, GARDEN AND ORCHARD in May and June. The larvae mine in the roots of these plants and transform to pupae in small earthen cells among the roots, from which the beetles come forth in the spring to attack the foliage of the plants mentioned. According to Johannsen, (I. c.) the larvae feed mainly on the roots, root-stalks and tubers of the potato. When they feed on the tubers they are responsible for the condition described by growers as " pimply potatoes." There is but one generation per year in Maine and probably in the Northern States generally, according to the same authority. Injury is usually due to the feeding of the adult beetles which have come out of hibernation in the spring. These riddle the leaves by their feeding, with small holes which look like they might have been made by a charge of fine birdshot. Occasionally the larvae injure seed tubers in the spring, but this is rare. Fig. 231. — Larva of potato flea-beetle. (After Johannsen, 1. c.) The Eggplant Flea-beetle* so nearly resembles the previous species that it will not be distinguished from it but by the entomol- ogist. It is slightly larger, however, with the wing-covers more hairy, and the groove at the base of the thorax is not so distinct. It has much the same food-plants, but is particularly abundant on eggplant, and is more commonly injurious in the South, below the Ohio and Potomac rivers. The Tobacco Flea-beetle f has been previously discussed (page 212) but should be mentioned, as it is commonly injurious to potato, tomato, and eggplant throughout the South, as well as to tobacco, and occasionally to corn and other plants. Control. — It has been found that Bordeaux mixture acts as an excellent repellant against these little beetles, and that plants well covered with it are not seriously injured. Inasmuch as it is always advisable to spray potatoes as soon as they are a few inches high for fungous diseases and for the Colorado potato beetle, by applying the spray as soon as possible after the plants * Epitrix fiiscula Cr. t Epitrix parvula Fab. INSECTS INJURIOUS TO POTATOES AND TOMATOES 269 are up they will be protected. Both potatoes and tomatoes should be sprayed with Bordeaux mixture and arsenate of lead or Paris green as soon as they are a few inches high. The spray should be applied liberally so as to give the plants a distinct coating of the mixture. Tomatoes are particularly susceptible to injury and might be dipped in arsenate of lead when planting, using 1 pound to 10 gallons of water. The destruction of the weeds upon which the larvae commonly develop is obviously important in preventing their multiplication. Where injury by the larvae is done to the tubers, it is recom- mended that they be dug as soon as possible, and be left ex- posed to the sun for a few hours after digging so as to harden the skin, before being stored. If damage continues in storage, the tubers may be fumigated with carbon bisulfide, as recommended for grain insects. Potato-scab and Insects That certain forms of what is commonly termed "potato- scab" are due to the work of insects has frequently been shown. In 1895 Professor A. D. Hopkins,* of the West Virginia Agricultural Experiment Station, reported some very careful original investiga- tions upon two species of gnats, Epidapiis scabies Hopk. and Sciara sp., the larvae of which had been conclusively shown to cause a "scab'' upon the tubers by boring into them. The larvae or maggots of the Potato-scab Gnat are about one-sixth of an inch long, and are the young of a wingless gnat shown, very greatly enlarged, in Fig, 232. The females deposit their eggs on the potatoes in storage from autumn to spring, and the maggots hatching from them enter old scab spots or injured places. Under favorable conditions a generation may be developed in twenty to twenty-five days. Later in the spring the eggs are deposited in manure or other decomposing material, on seed potatoes or on growing tubers to which they may be carried on seed potatoes. When they become well established in a potato, it is soon de- stroyed if they are not overcome by their natural enemies, or unless the soil becomes dry, when they soon disappear. In- fested places look very much like the ordinary scab produced by the scab fungus and may be readily mistaken for it. Such * A. D. Hopkins, Special Bulletin 2 (Vol. IV, No. 3), W. Va. Agr. Exp. Sta., p. 97. 270 INSECT PESTS OF FARM, GARDEN AND ORCHARD injury was quite general and serious in West Virginia in 1891 and 1892. Dr. Hopkins found that "they breed in and are especially common in barnyard-manure," that "excessive moisture in the soil has been observed to be the most favorable condition for their development," and that "soaking the seed-potatoes in a solution of corrosive sublimate previous to planting " will kill all the eggs and young larvae, as it will also destroy the spores of the potato-scab fungus. Professor H. Garman* has also recorded the injuries of several species of millipedes, or "thousand-legged worms," Cambala annulata and Parajulus impressus, as causing a scab by gnawing into the surface of the tubers. Though both of these observations are unquestionably true, such injury has not occurred in other Fig. 232. — Potato scab-gnat {Epidapus scabei Hopk.); a, fly; i, larva; g, egg; h, egg mass — much enlarged. (After Hopkins.) parts of the country, and it is improbable that any large portion of potato-scab is due to these insects. Potato-scab is a fungous disease, which, as already noted, may be destroyed by soaking the seed-potatoes in a solution of corrosive sublimate. Blister-beetles f Long before we had made the acquaintance of the Colorado potato-beetle, several species of blister-beetles frequently brought themselves into notice by their injuries, and, therefore, are now known as the "old-fashioned potato-bugs." The name of "bhster-beetles" has been bestowed upon them because of the blistering effect which they have upon the skin, they being nearly related to the Spanish fly, used for that purpose. One of the most common of these is the Striped Blister-beetle, which has three yellow stripes upon its wing-covers, while * H. Garman, Bulletin 61, Ky. Agr. Exp. Sta., p. 18. t Family Meloidae. INSECTS INJURIOUS TO POTATOES AND TOMATOES 271 two other common forms are of a slate-black color. Very often when these' beetles congregate in numbers they are a great nuisance, not only in the potato-patch, but upon many other plants of the garden or truck-farm. Unfortunately, they present to the farmer a very peculiar problem, for while the beetles are often exceedingly injurious, the larvae are beneficial, eating large quantities of grasshoppers' eggs Life Histonj. — The life of these insects is unique. The female lays a large number of eggs in a small cavity in the earth, and from these hatch some small, long-legged larvae, which run about searching for the pod-like masses of grasshoppers' eggs, upon which they feed. As soon as the appetite of one of these little egg-hunters is appeased, he sheds his skin, and now being sur- rounded by food and no longer needing his long legs for running, in the next stage of his existence his legs become very short and rudimentary, and he remains almost immobile while feeding upon the rest of the eggs Control. — Spraying with Paris green or arsenate of lead, as advised for the Colorado potato-beetle will kill the beetles, and where the vines have been regularly sprayed but little trouble will be had with them Where they suddenly appear in large swarms in gardens or on truck land, they are often destroyed by a line of men and children slowly driving them with branches, as the beetles move but slowly If a ditch is available it may be oiled, and the beetles destroyed like grasshoppers, or they may be driven into a windrow of straw, hay, or any inflammable rubbish and burned in it. Three-lined Leaf-beetle * Closely related to the Colorado potato-beetle, and very similar to it in habits, is the Three-lined Leaf-beetle. The eggs may be distinguished by the fact that they are usually laid in rows along the midrib on the under side of the leaf, while those of the potato-beetle are laid indiscriminately in bunches. The larvae, however, may be readily distinguished from all other insects attacking the potato by being covered with a disgusting mass of their own excrement. * Lema trilineata Oliv. Family Chrysomelidce. 272 INSECT PESTS OF FARM, GARDEN AND ORCHARD Fig. 233. — Three-lined leaf -beetle {Lema trilineata Oliv.); cf, larva; h, pupa; d, eggs; beetle at right. (After Riley.) There are two broods during the season, the larvae of the first appearing in June, and those of the second in August; but the beetles of the second brood do not emerge until the following spring. In other respects the hfe history is practically the same as that of the Colorado potato-beetle. The beetle is of a pale yellow color, with three black stripes on its back, and in a gen- eral way resembles the common striped cucumber- beetle (Diahrotica vittata Fab.), though it is somewhat larger and the thorax is decid- edly constricted. In case it becomes necessary to destroy the blister-beetles, both they and the three-lined leaf-beetle may be readily disposed of by applying arsenicals as advised for the Colorado potato-beetle. The Potato Aphids * The potato aphid, also called the pink and green aphid of the potato because it occurs in both these colors, is a widely distributed pest which occasionally does a considerable amount of injury to the potato. It attacks, beside the potato, the pepper vine and several other unrelated plants. The insect is large for an aphid, and may be either pink or green, and lacks the dark markings characteristic of many species of aphids. The aphids are found in the spring and early summer feeding on rose bushes and possibly other plants and from these they migrate about mid-summer to potato and other food plants. Both winged and wingless forms migrate, an unusual occurrence as ordinarily only winged individuals take part in the migration. In late summer and early fall the reverse migration takes place. Not a great part of the season is spent on the potato but in the time the aphids are present they are able to do a great amount * Macrosiphum solanifolii Ashmead. See Dr. Edith M. Patch, Bulletin 242, Maine Agr. Expt. Sta. INSECTS INJURIOUS TO POTATOES AND TOMATOES 273 of damage when they are at all numerous. In addition to the direct injury the aphids do they create conditions favorable for fungus attack, the wounds made by their beaks serving as points of infection and the weakened condition of the plants making them less resistant. This species has been reported from Maine and California and in many intermediate localities. Control. — Dr. Patch, (1. c ), states that since the insect winters Fig. 234.— The potato aphid. Winged summer form. Agr. Expt. Sta.) (After Webster, Iowa in the egg stage on many plants near potato fields, clean culture and destruction of weeds in the fall should be a valuable means of control. She recommends, also, spraying rose bushes showing infestation in the spring with tobacco extract and later, if necessary spraying the potatoes with the same material. The Apple Leafhopper * The apple leafhopper is so named from the fact that it is found on apples, especially on yoimg trees in the nursery. To these it is quite seriously injurious, being often the most important insect pest found in apple nurseries. It is called also the potato leafhopper because it attacks potatoes and is even more injurious to them than it is to the apple. * Empoasca mali LeBaron. Family Jassidoe. See Bulletins 111 and 155, Iowa Expt. Sta., E. D. Ball, Journal of Econ. Ent., Vol. 12, No. 2, 1919, pp. 149-154. Fig. 235.— The apple leaf hopper. (After A. J. Ackerman, Bull. 805, U. S. Dept. of Agr.) A, first nymphal stage; B, second stage; C, third stage; D, fourth stage; E, fifth stage; F, side view of fifth stage; G, adult;//, front view of head of adult; /, eggs in tissue on underside of apple leaf; J, curled condition of ter- minal leaves due to attack by the apple leafhopper on apple. 274 INSECTS INJURIOUS TO POTATOES AND TOMATOES 275 The leafhopper in question is a small insect of slender form, about one-eighth inch in length. The adults have wings and are also provided with hind legs fitted for hopping and are quite active. The young hop to some extent but are much less active than the adults. They winter usually as adults but are said also to pass the winter in the egg stage, the eggs being laid in the fall on the food plant. There are three or four generations. Injury to potato is of two kinds; first, the direct injury due to the sucking of sap by the leafhopper and second, the blighting of the leaves said to be caused by the leafhopper. There is some doubt as yet as to just how much the leaf hoppers have to do with the transmission of the disease which is called the tip-burn or hopper-burn but Dr. Ball, (1. c.) has presented a very strong case against the hopper. He maintains that the tipburn is the result of a specific poison injected by the hoppers or a specific infection carried by them. The evidence may not be quite conclusive and is still the subject of investigation, but there are at least strong probabilities that the case against the hoppers will be proven. The problem is complicated by the fact that there may be more than one kind of tipburn or tip blight, as a trouble of very similar nature has been observed by the writer in fields where no leaf- hoppers were to be found. This burn was generally ascribed to weather conditions. Control. — Control measures against this pest on potato have not been very well worked out, but it is probable that clean culture and spraying with nicotine preparations will be found to give the best results. Tomato Worms The large green horn-worms which attack the foliage of the tomato are the same as those previously described which attack tobacco. Usually they are not so numerous but that they may be readily controlled by handpicking, but if necessary the same remedial measures may be used as advised for them on tobacco. The Tomato Fruitwonn The worms which commonly bore into the green and ripening tomatoes are the same as the tobacco budworm and the cotton E-152 GARDEN CUTWORMS Pupa The fulljrown catworm burrow; into the soil and changes to a pupa from which a moth ^ emerges in late /■ ^; summer. Themothblay ef5's on grasses or weed s or on ground .The eg?s soon hatch and the young worms from them feed on the same plants or al- ; most any late crop till near- lyfulI?rown Inlatefallthqr bury themselves deep in the ground for protection during winter Insprm? they emer je and attack most any youn? and tender plants they find at the surface. Young* catbag^e plant destroyed by a cut-worm The culprit hiding in ground / "' during day near / " the plant. ^v \ \\ » \ t % k ■ \ f i A-. . \ Li , ■ iM^ ^^^ 1 ■ Fig. 251. — The pea-aphids on stems of red clov' er — natural size. (After Folsom.) INSECTS INJURIOUS TO BEANS AND PEAS 295 By midsummer, with the harvesting of the peas, most of the aphids upon them have been destroyed by predaceous and para- sitic insects and disease, and they are not observed during late sum- mer unless they have been subsisting on clover throughout the season, when they sometimes destroy the crop in August, as has been observed in Illinois. In early fall they often become com- mon again on late garden peas, and late in October they migrate to clover. Fewer young are born as the weather gets colder in the fall, and the aphids never become numerous enough to do any injury at that season. Late in October and early November — in the Middle States — as the aphids are migrating to clover, winged males appear, and some of the wingless females developing on clover produce eggs. The winged males are similar in size and color to the migratory females, though slightly darker, and have three or four dark spots along the sides of the abdomen and a deep brown dash on either side of the back of each abdominal segment. The oval eggs are about one-fiftieth inch long, jet black, and are deposited on the lower leaves or stems of clover, and hatch as it commences to grow in the spring. In central Illinois they were observed to hatch March 23d, and the young became full grown and commenced reproduction on April 5th, living until May 12th. In southern Maryland and farther south many of the viviparous females live over winter on the clover and commence to reproduce again in the spring, no eggs having been observed in that latitude, but in central Illinois and northward, the females are probably entirely destroyed by the cold and only the eggs survive. Natural Enemies. — From 5 to 10 per cent of the aphids are normally destroyed by little wasp-like flies of the genus Aphidius whose larvae live within the aphids. A number of the more com- mon ladybird-beetles,* syrphus-flies,t and lace-winged flies, J which commonly prey upon aphids, destroy large numbers of the pests, but their work comes so late in the season that the peas are seriously injured long before the aphids are checked by them, though they might prevent a reappearance the next year. The most important enemy of the pea-aphis is a fungous dis- ease (Empusa aphidis) which is undoubtedly the principal factor in its natural control. The most probable explanation of the * Family Coccinellidce. t Family SyrphidcB. X Family Chrysopidoe. Concerning these predaceous insects, see Chap. I. 296 INSECT PESTS OF FARM, GARDEN AND ORCHARD remarkable outbreak of the pea-aphis in 1899 and 1900 seems to be that, due to two exceptional!}^ dry springs, the fungus was unable to develop, as it propagates best in damp weather, and the aphids increased unchecked. Though occasional individual aphids were found killed by the fungus early in the season, not until June 11, 1900, were diseased aphids found in any quantity, but after that so swiftly did the disease destroy them that a week later but few aphids were to be found and almost all were diseased. Probably this fungus usually destroys the aphids on clover before they have become excessively numerous or have migrated to peas. Control. — Inasmuch as the aphids spread from peas to clover, the latter crop should not be planted near peas when avoidable. In the spring the aphids should be carefully observed on the clover and if they become excessively abundant, the only way to prevent their migration to peas is to plow under the clover deeply and roll the field. Highly fertilized land in which the moisture is retained by fre- quent cultivation very often enables a crop to mature in spite of moderate injury. Peas sown broadcast or planted in 8-inch drills have been much more seriously injured than those planted in rows 18 to 30 inches apart and cultivated, and those planted close together afford no opportunity for brushing or cultivating as described below. Early varieties of peas have practically escaped injury where late varieties have been wholly destroyed, so that it is obvious that only the earliest varieties should be grown where injury is anticipated. Early in 1900 Professor W. G. Johnson found that when peas were planted in rows that the aphids could be readily knocked from the vines by means of brushing with a branch, and that by follow- ing the brushes with cultivators, the aphids would be covered with earth and destroyed, either by suffocation or by the heat of the soil. Where the air temperature is 95° F. the soil will be nearly 120°, and aphids brushed onto it will be actually roasted to death in a few minutes. The cultivation should not be repeated for about three days, as it requires about that time for the destruction of the insects covered with earth, if it is not hot enough to kill them at once. By this method large areas of peas have been saved fiom destruction. ? INSECTS INJURIOUS TO BEANS AND PEAS 297 Though the above methods will destroy quantities of the aphids and thus prevent the destruction of the crop, they do not dislodge the young aphids in the terminals, and therefore cannot be reKed upon to prevent all injury. Practical field tests have shown that this may be done by spraying with whale-oil soap, 1 pound to 6 gallons of water. In small gardens this may be applied by means of bucket or knapsack pumps, and on small acreages with a barrel sprayer with a row-spraying attachment having noz- zles arranged so that the vines will be thoroughly covered from each side. The spray must be applied with considerable pressure so as to force it into the terminals. Here again nicotine compounds have largely displaced the soap and oil sprays, although soaps are largely used in connection with the nicotine. Mr. L. M. Smith recommends the use of the following formula " Black-leaf 40" 10 ounces Whale-oil soap 14 pounds Water 50 gallons He also recommends that the spraying be done on a bright clear day so as to avoid injury to the vines from the spray material. * The Pea-moth f The Pea-moth is an old pest in Europe, whence it was imported into Canada, where it has frequently done considerable mischief. It is known to occur in the large pea-growing sections of |^^ New Brunswick, Nova Scotia ^^^^^^^M^^^ZJ^^'^^J and Ontario, where it first at- ^ tracted attention near Toronto ^'^^^ M ^^ in 1893, and was found in the pea growing section of Michigan j^-xf ^ ' r^A^v' in 1908. The wings of the adult W^ ^^SSL^^iT ^ moth expand about one-half -^^^^^^^^^^"^^^^m^ an inch, the fore-wings being -r^^^ cy-^, rp, „ „„„ _„,, /r, ' * ° riG. J,ol. — ine pea-moth {kemasia "dark, fuscous or dusky, tinged nigricana Steph.): moth above, with darker brown and mottled IS.™ JtnS ChitUd"" with white," the hind-wings U. S. Dept. Agr.) being a uniform fuscous with a rather long inner fringe of hairs, as shown in Fig. 252. The females may be found flying around pea-blossoms soon * L. M. Smith, Virginia Truck Expt. Sta., Bulletin for October, 1914. t Semasia nigricana Steph. Family Tortricidce. 298 INSECT PESTS OF FARM, GARDEN AND ORCHARD after sunset, and deposit one to three eggs on young pods. The caterpillar hatches in about fourteen days, according to European observations, and attacks the forming seed. Affected pods usu- ally ripen early. The larva is whitish-yellow with a pale brown head and thoracic plate, and about one-half an inch long when full grown. With the opening of the pod the larva crawls out and enters the earth where it spins a very thin silken cocoon. The length of the pupal stage and the method of hibernation do not seem to be well established. Very early and very late varieties are but little injured. Remedies. — This suggests one of the best means of handling this pest to be the growing of early varieties, such as Alaska, American Wonder, Gregory's Surprise, Nott's Excelsior, and McLean's Little Gem. If the crop is known to be infested, clean up the vines and burn them as soon as it is picked. Spraying with arsenate of lead will doubtless aid in the control wherp in- festation is serious. CHAPTER XVI INSECTS INJURIOUS TO BEETS AND SPINACH * The Beet-aphis f This species was first described by Mr. W. R. Doane in 1900 and seems thus far to have been found only in Washington and Oregon. " Attention was first called to this pest," he says,t " in 1896, when it was found that a field of two or three acres of beets was generally infested, a strip of twenty-five to a hundred yards being so badly injured that the beets were nearly all soft and spongy, and the plants much smaller than the average. " It has been even more destructive in Oregon than in Wash- ington, at least a thousand tons of beets having been destroyed by it in one year in a single valley devoted largely to beet-culture. Like very many other beet-insects, this species infests also several wild or useless plants. " The smaller root- lets of the beet are first attacked by this aphis, and if it occurs in con- siderable numbers these are soon all destroyed, and the leaves thereupon soon wither, and the whole beet shrivels and becomes spongy. This wilting of the leaves will Fig. 253. — The beet-aphis (Pemphigus betce Doane) : a, winged female ; b, wingless fe- male; c, antenna of winged female. (After Doane.) frequently, in fact, be the first thing to attract the attention of the beet-grower. The actual injury to the crop will, of course, depend * See Forbes and Hart, Bulletin 60, 111. Agr. Exp. Sta., and F. H. Chitten- den, Bulletin 43, n. s., Div. Ent., U. S. Dept. Agr. t Pemphigus betce Doane. Family Aphididoe. i Bulletin No. 42, Wash. Agr. Exp. Sta. 299 300 INSECT PESTS OF FARM, GARDEN AND ORCHARD largely upon the time when the attack of the aphis is made. If the plants are small they may be readily destroyed, while if they are practically full grown the loss of the small rootlets will not materially affect them. " No sexual generation of this aphis has as yet been discovered and no eggs have been seen, viviparous reproduction continuing throughout the year except when the cold of the winter tempo- rarily suspends the physiological activities of the species. The winged females, appearing from time to time during the summer and fall, serve to distribute the species generally, new colonies being started wherever these females find lodgment and food. In districts liable to injury by this insect it seems inadvisable that beets should be the first crop on new land, or that ground should s^ be continued in beets or in any other y Nv root-crop after the pest had made its /\\ \ appearance in the field." >^^y^ ' [) Another plant-louse, called the beet f^'^^r^xr^^^^.^...^^ root-aphis*, proved injurious to sugar- J ^ H^^^ ^^®*^ ^^ Colorado in 1903. They were S ^ found " quite generally distributed in ^.^ ^.^^_^„^^^. the beet-fields in the vicinity of ^^^^ \^^\^^ Rockyford and attacking the roots of ^ ^ "" many weeds." What seemed to be this Fig. 254.-Beet root-aphis ^P^cies was very abundant upon the {Tijchea brevicornis Hart) : roots of the common garden purslane, to rial'gre'SlrSarg'S: which it was very injurious. Near Fort (After Garman.) Collins a badly infested field of sugar- beets was also seriously damaged. No practical means for controlling these pests seems to have been recorded, so that in case of injury the entomologist of the State should be consulted. White Grubs, Wire worms, and Cutworms Fortunately for the sugar-beet farmer the worst insect ene- mies of that plant feed upon the tops, and very rarely do we hear of serious damage being done the roots. In the East most of the damage to the roots is done by those familiar old farm-thieves, the white grub, the cutworm and the wireworm. As a general rule * Tychea brevicornis Hart. INSECTS INJURIOUS TO BEETS AND SPINACH 301 they will be found to be worse on lands previously in sod, which should therefore be avoided when known to be badly infested with either of these insects, as both are difficult to fight after they have once commenced doing noticeable injury. The life histories and means of control for these pests will be found discussed in Chapter VII. The Sugar-beet Webworm * The sugar-beet webworm is very similar to the garden web- worm, and is so named because it has developed as a serious Fig. 255. — The sugar-beet webworm [Loxosfege sticticalis Linn.): 1, moth; 2, eggs; 3, 4, larvae; 5, pupa; 6, winter tube of larva, opened at a to show pupa — 1, 3, 4, 5, enlarged. (After Gillette, Colo. Agr. Exp. Sta.) pest of the sugar-beet in Kansas, Nebraska, and Colorado. It has been noted as injuring tansy in Michigan, and feeds on * Loxostege sticticalis Linn. Family Pyraustidm. See C. P. Gillette, Bulletin 98, Colo. Agr. Exp. Sta., and references there given. 302 INSECT PESTS OF FARM, GARDEN AND ORCHARD cabbage, onions, and alfalfa, as well as pigweed (Chenopodium album) and careless weed (Amaranthus) and will probably feed on many other crops. It is a native of western and central Europe, and northern Asia, and was evidently introduced on the Pacific Coast, as it was noted in Utah in 1869. The moth is larger than the garden webworm, having a wing expanse of an inch, and is a purplish-brown color with darker and paler bands as shown in Fig. 255. The full-grown larva is about an inch long, of a dark color with a white stripe down the back and one along either side, and marked with numerous black and white tubercles as illustrated. Life History. — The larvae hibernate over winter an inch or two below the surface of the soil in long silken tubes. In spring they pupate in these tubes and the moths emerge about the middle of May. The eggs are laid on the foliage either singly or in clus- ters of from three to ten, one overlapping another. The egg is broadly oval, one twenty-fifth inch long, and of a pale green color. The first generation of caterpillars feed on pigweed and alfalfa in Colorado during June. A second generation of larva; occurs about the middle of July and sometimes injures beets, but the third generation about the middle of August is the one most injurious in Colorado. Most of these larvae hibernate over winter, but there is a partial fourth generation in Colorado. The larvae defoliate the plants, and cover them with a web the same as the native garden webworm, with which the life history seems to be practically identical. Control. — The same means of control as for the garden web- worm are advised. The Beet Army Worm * " This caterpillar, which replaces the fall army worm (L. frugiperda — see Chapter VII) in the Western States, differs from it by its more decidedly mottled ground-color, by a row of white dots at the lower margin of the lateral dark band, and by the yellower color of the light stripes. It is an interesting fact that while the preceding species was doing serious, unusual, and widely extended injury in the Eastern and Southern States (1899,) the present one was similarly abundant in Colorado, where, * Laphygrna exigua Hubn. Family Noctuidce. INSECTS INJURIOUS TO BEETS AND SPINACH 303 besides destroying many kinds of weeds and grasses, it com- pletely defoliated thousands of acres of sugar beets. In some cases where the foliage of the beet did not furnish it sufficient food, the root was attacked and the upper surface was com- pletely gnawed away. Late plantings, of course, suffered most severely, especially when surrounded by newly broken ground. The weeds most generally eaten were pigweed, salt- weed, wild sunflower, and Cleome. Potato, pea, and apple leaves were also devoured. These injuries oc- curred about the middle of August, at which time the larvae and pupae were abun- FiG. 256. — The beet army worm (Laphygma exigua Hubn.): a, moth; h, larva, side view ; c, larva, back view; d, head of larva; e, egg from above; /, egg from side — all enlarged. (After Chittenden, U. S. Dept. Agr.) dant, and a few moths laden with eggs were noticed." This species evidently hibernates as a moth, and at least two broods of larvae may be looked for each year, the first about June and the second in August. The species has been reported thus far from Colorado and California, but it doubtless has a more extended range in the mountain regions of the far West. " Professor Gillette's field-experiments showed that it could be destroyed by dusting or spraying arsenical poisons on the leaves." Flea-beetles Several species of flea-beetles, chiefly Systena toeniaia, Systena hudsonias, Disonycha triangularis, and Phyllotreta vittaia, often do considerable injury by gnawing small holes in the upper and lower surfaces of the leaves of beets, giving them an appearance as if affected by leaf-spot, or puncturing them full of small holes, and thus stunting the growth of the plants. 304 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Spinach Flea-beetle * Of the many species of flea-beetles injurious to sugar-beets, the spinach flea-beetle is one of the largest and most destructive. The beetle is nearly one-quarter inch long, shining black, with a greenish or bluish lustre. The prothorax and abdomen are red or reddish yellow, and the legs and antennae are pale yellowish. It occurs from New England to Montana and southward to the Gulf, and is one of the most common pests of beets and spinach, while its native food plants are chickweed and lambsquarter. Life History. — The beetles hibernate over winter and emerge in the spring during April and May. The buff or orange eggs are laid on end in small masses, " at the bases of the plants infested, on bits of leaf or earth, or even within the earth " according to Forbes. The eggs hatch from sometime in April to early July, according to locality. The larvae usually feed on the under side of the leaf, keeping to- gether in families which migrate from Fig 257. — The spinach flea-beetle (Disonycha jgg^f j-q jgg^i' ^ Jj j J g xanthomelcena Dalm.) : a, beetle; b, egg mass; bb, sculpture of egg; c, larva; c/, pupa; e, young young, and drop to the larva; /, abdominal segment of sam^a c d ground — as do the five times natural size; b, more enlarged; bo, ° f, highly magnified. (After Chittenden, U. S. beetles — W hen d 1 S- Dept. Agr.) turbed. While young they merely gnaw the under surface of the leaf, but later they eat through and riddle it with round holes, in which they are aided by the beetles. The full-grown larva is about one-quarter inch long, of a dull gray color, except on red and purple beets, on which it assumes the color of the plant attacked, is of a cylin- * Disonycha xanthomeloena Dalm. Family Chrysomelidoe. See F. H. Chit- tenden, Bulletin 43, Bureau of Ent., U. S. Dept. Agr., p. 14; S. A. Forbes, 21st Rept. State Ent. of 111., p. 116. INSECTS INJURIOUS TO BEETS AND SPINACH 305 drical form, and the segments are strongly marked by rows of raised tubercles, each of which bears a black hair at the tip. The larvae become grown in late June and early July in Illinois, and enter the earth to pupate, the beetles of the next generation emerging about a month after the eggs were deposited. The beetles of the second generation lay their eggs from July to September and the beetles mature before winter sets in. In the District of Columbia, Chittenden observes that the first generation is more abundant on chick-weed and the second is injurious to beets and spinach. Control. — Thoroughly dusting or spraying the plants with arsenate of lead will readily destroy the larvae and probably most of the beetles. As in combating all flea-beetles the destruc- tion of the weeds upon which they multiply is important. The Larger Beet Leaf-beetle * One of the principal pests of the sugar-beet in Colorado and adjacent States is a rather large brownish leaf -beetle which with its larvae destroy the foliage or so injure it that the plant dies. It is often locally known as the " alkali bug " from the fact the injury is mostly on alkali soil or land near it, and *' french bug," probably from the "frenching^" of the fohage. The beetle is from one-quarter to one-third inch long, and rather resembles the elm leaf-beetle, varying from pale yellow to black, with the wing-covers striped as shown in Fig. 258. Several wild plants, including blites, Russian thistle, and saltbushf probably furnish the normal food of the insect. " The beetles are gregarious, ' sometimes occurring in swarms like bhster-beetles.' Their brownish-gray eggs are deposited in irregular masses, usually on the under sides of the leaves. They hatch in about six days, and their larvae or young commence feeding at once, continuing for nine or ten days, when they dig their way into the ground, a few days later coming forth as beetles. Although the beetles do much injury, the principal damage is sometimes accomplished by the larvae, hundreds being found on a single plant, which is either consumed or so injured that it shrivels and dies. The larva, shown in the illustration, measures * Monoxia jnmcticollis Say. Family Chrysomelidce. t Dondia americana and D. depressa, Salsola tragus, and Atriplex argentea. 306 INSECT PESTS OF FARM, GARDEN AND ORCHARD when full grown about one-third of an inch in length. The general color is nearly uniform dark olive brown, the conspicuous piUferous tubercles being pale yellow, and the head and portions of the legs black. The eggs are dull brownish gray, and the surface, as seen through a lens, is covered with septagonal and hexagonal areas."* Control. — Paris green diluted with flour and dusted over the foliage has effectively controlled the pest, and probably any thorough application of any arsenical either wet or dry would be effective. Professor C. P. Gillette f has observed that the beetles accumulate on the " mother " beets early in the spring, so Fig. 258. — The larger beet leaf-beetle {Monoxia pundicollis Say): a, female beetle; b, eggs; c, d, larvae from above and side; 'b, claw of male; o, claw of female — all much enlarged. (After Chittenden, U. S. Dept. Agr.) that if a few beets were left in the ground over winter they might serve as trap plants for the protection of the younger plants in spring. As injury is mostly on or near alkali ground, such soil should be avoided. * Quoted from F. H. Chittenden, Bulletin 43, Bureau Ent., U. S. Dept Agr., p. 10. t C. P. Gillette, 24th Report Colo. Agr. Exp. Sta. (1902), pp. 108-111. INSECTS INJURIOUS TO BEETS AND SPINACH 307 The Beet Leafhopper * Very serious loss to the sugar-beet industry has occurred in Colorado, California and Utah from a condition known as " curly leaf " or " blight." Investigations made by Professor E. D. Ball have shown that the " curly leaf " is undoubtedly caused by the presence of immense numbers of small leafhoppers, from 10 to 100 often being found on a plant in badly infested fields. The curly leaf condition does not seem to result, however, except when the Fia. 259.— The sugarbeet leafhopper (Eutetiix tenella Baker): a, adult; h, nymph; /, eggs — greatly enlarged; g, section of beet stem showing fresh eggs in place; h, same showing eggs ready to hatch; i, old egg scars on beet stems; j, small leaf of sugar beet showing characteristic "curly-leaf" condition; k, enlarged section of back of an extreme case of curly-leaf showing warty condition of veins. (After Ball, U. S. Dept. Agr.) soil has become dry and heated, and where plants are shaded or irrigated the damage by the leafhoppers does not seem to produce * Eutettix tenella Baker. See E. D. Ball, Bulletin 66, Part IV, Bureau of Entomology, U. S. Dept. Agr., and Bulletin 155, Utah Exp. Sta. 308 INSECT PESTS OF FARM, GARDEN AND ORCHARD the same trouble. Similar injury has been noted in parts of Oregon, but not of so serious a nature. The beet-leafhopper is a pale yellowish-green species (Fig. 259), one-eighth to three-sixteenths inch long, and when fly- ing appears almost white, so that it is sometimes locally called the " white fly." Life History. — The hibernating habits of the adults and their food-plants in the spring have not been well determined. They Fig. 260. — "Hopperette" designed for collecting leafhoppers. (After G. C. Davis, Mich. Agr. Exp. Sta.) appear in the beet-fields late in June and lay their eggs in the leaf-stems, the eggs hatching in about two weeks. The young nymphs appear in July and are very active, being first found in the unfolding leaves at the centre and later spreading to all parts of the plant. The nymphs are variously colored, but the com- monest form is a pale creamy color with a brown saddle on the INSECTS INJURIOUS TO BEETS AND SPINACH 309 middle of the abdomen and various mottlings on the prothorax andwingpads. The nymphs become full grown in from sixteen to twenty-two days and the adults again become abundant in August and September; they evidently hibernate as adults, as no more eggs are laid in the fall as far as observed. The characteristics of the " curly leaf " are described by Dr. Ball as follows: " The first symptom of * curly-leaf ' or ' blight * of the beet is a thickening of all the smaller veinlets of the leaf, giving it a roughened appearance on the under side. This is followed by a cm-ling of the edge and a final rolhng up of the leaf, the upper surface always being rolled in. As this progresses the smaller veinlets grow still larger and more irregular, knotlike swellings appear at frequent intervals, and in extreme cases little nipple-like swellings appear, extending to a height of nearly one-fourth of an inch. This will be noticed first on a medium- sized leaf, gradually spreading to the younger ones, while at the same time the beet almost stops growing and a large number of fibrous roots are sent out. . . . The beet often continues in this way throughout the season; in bad cases it shrivels and dies, while in a few instances there is a partial recovery and a new set of leaves, though the sugar content remains very low." Control. — Practical measures of control do not seem to have been very thoroughly tested. With a better knowledge of the hibernating habits of the species, it may be possible to reduce its numbers at that time. After the hoppers have appeared in numbers they must be dealt with promptly. " A thorough spraying with kerosene emulsion at a strength of 1 part of the stock solution to 5 parts of water, would destroy most of the insects that it hit, and by using a drag in front of the nozzles to turn the leaves over and cause the insects to jump, most of them would be reached." This would probably need to be repeated in about ten days. Hopperdozers have often been successfully used for collecting various forms of leafhoppers. A modifica- tion of the form used against grasshoppers with a couple of wings extending out on either side of the row and covered with a sticky substance such as " tanglefoot " or that described on page 458 would undoubtedly prove effective in collecting the adults, particularly before the females have laid their eggs, when they are more readily caught. A "hopperette " designed by Professor 310 INSECT PESTS OF FARM; GARDEN AND ORCHARD G. C. Davis for use against leaf hoppers on celery in Michigan, is shown in Fig. 260, and may be readily attached to the frame of a wheel hoe. The string across the notch at A strikes the plants and causes the hoppers to jump at the right time. By adding high wide wings to either side of this machine it should be well adapted for beets and similar crops. However, even the capture or killing of large numbers of the leafhoppers by the means suggested will not, according to Dr. Ball, solve the question of preventing the disease they carry, since a single puncture will often kill a leaf. Some means for the destruction of the hoppers before they reach the beet fields will be necessary before the disease can be eliminated. The outlook for certain beet-growing sections is, therefore, still serious. Blister-beetles * Among those insects attacking the young sugar-beets and often doing considerable damage after they have become partly grown, few are more widespread or do more general injury than the blister-beetles. They have been especially destructive in the northern Mississippi Valley, where they are usually worst after a period of unusual abundance of grasshoppers. Coming suddenly in a large swarm, they settle in a field and thoroughly FiQ. 261. — The striped blister-beetle (Epicauta vittata): a, female beetle; h, eggs; c, triungulin larva; d, second or caraboid stage; e, same as / doubled up as in pod; /, scarabseoid stage; g, coarctate larva — all except e enlarged. (After Riley and Chittenden, U. S. Dept. Agr.) riddle the foliage with holes or strip it bare before going to another field. One of the most common forms is the striped blister-beetle, or " old-fashioned potato-bug " {Epicauta vittata), which is * Family Meloidce. INSECTS INJURIOUS TO BEETS AND SPINACH 311 shown in the illustration, together with the immature stages. The ash-gray blister beetle (Macrobasis unicolor) is also a common form, shown in Fig. 247. Three or four other forms are common throughout the country, but are especially numerous in the West, where grasshoppers are more abundant. The reason for this is discussed, along with an outline of the life-histoiy, in Chapter VII under the heading of natural enemies of the grasshoppers. Remedies. — However, when they swarm into the beet-fields, potato- or garden-patches, one cannot afford to allow them to consume one crop for the good they may do in saving another from still another insect scourge. So be ready for them on their first appearance; give the plants a thorough spraying with 1 pound of Paris green and 1 pound of lime to 125 gallons of water. It may be well to spray with Bordeaux mixture, which will prevent various fungous diseases, and with which Paris green can be used much stronger without danger of burning the foliage; or it may be applied dry by mixing with from ten to twenty parts of flour or plaster, dusting it on in early morning, while the dew is still on the plants. Arsenate of lead sprayed at the rate of 3 pounds to 50 gallons, or used as a dust, will be equally effective, will adhere to the foHage better, and will be less likely to burn the f ohage. The Beet or Spinach Leaf-miner * Frequently beet and spinach leaves will be found with tor- tuous mines or large blotches which have been mined out by small white maggots beneath the surface epidermis. This injury is most commonly due to the maggot of a small fly shown in Fig. 262. " The ground color is gray with the front of the head silver white. The body, including the legs, is somewhat sparsely covered with rather long stiff black hairs. When in action the body is usually carried in a somewhat curved position, but when extended measures nearly a quarter of an inch. The maggot if) is white, and so nearly transparent that the contents of the abdomen can be seen through the posterior portion." Life History. — " The flies, by close observation, may be seen in flight just above the ground or hovering about their different food plants. The eggs are placed on the lower surface of the * Pegomyia vicina Lintn. See Chittenden, I.e., from which the quotations are taken. 312 INSECT PESTS OF FARM, GARDEN AND ORCHARD leaves and arranged in masses of from two to five. When the young hatch they bury themselves within the leaf tissue, con- structing a thread-like mine which they afterwards extend in a curve or semicircle. Transformation to pupse takes place in most cases in loose soil, which the maggots enter to only a short distance, or under fallen leaves. Occasionally maggots trans- form within a leaf if the latter happens to rest on the ground. Dr. Howard states that the eggs hatch in from three to four Fig. 262. — The beet leaf-miner {Pegomyia vicina Lintn.): a, fly; h, head of male fly; c, head of female; d, surface of egg highly magnified; e, egg; /, maggot; g, head of same; j, anal segment; k, anal spiracles — all enlarged. (After Howard, U. S. Dept. Agr.) days, and the larval stage is passed in seven or eight days, the puparium or resting stage requiring from ten to twenty days. " Injury appears to be most frequent in late fall, but even in larger fields such a practice itiight prevent its increase may be due to earlier generations in midsummer. " In many cases infestation can be traced directly to the insect having bred in lambsquarters and similar weeds, which if not destroyed by ordinary methods of cultivation mature and die during October." INSECTS INJURIOUS TO BEETS AND SPINACH 313 Control. — Where this pest occurs in small gardens it may be controlled by picking and destroying the infested leaves, and even in larger fields such a practice might prevent its increase and consequent injury. Those insecticides which have been tried as remedies seem to have had no effect. Deep plowing and thorough harrowing of infested fields as soon as the crop can be removed should greatly lessen injury the next year. As this species seems to prefer spinach to beet, Dr. Chittenden has suggested that spinach might be used as a trap crop in large fields of sugar beets where the injury warranted such a measure. CHAPTER XVII INSECTS INJURIOUS TO CABBAGE AND RELATED CROPS * The Cabbage Maggot f Throughout the Middle and Northern States the cabbage mag- got is one of the most destructive and most difficult to combat of Fig. 263. — Cabbage root infested with maggots. (After Slingerland.) all the insects affecting cabbage, cauliflower and radishes. Just as the plants are commencing to make a good growth they sud- * See Garman, "Insects Injurious to Cabbage," Bulletin 114, Ky. Agr. Exp. Sta. t Phorbia hrassicce Bouche. Family AnthomyiidcB. See W. J. Schoene, Bulletins 382 and 419, N. Y. Agr. Exp. Sta., Journal of Economic Entomol- ogy, Vol. IV, p. 210. 314 INSECTS INJURIOUS TO CABBAGE, Etc. 315 denly appear sick, many are found wilting, and soon die. Exami- nation of the roots shows that they have been riddled by small, white maggots as shown in Fig. 263. Early-planted cabbage, cauliflower and radishes are particularly affected, and later in the season the maggots will be found on turnips and wild mustard. These maggots are the larvae of a small fly, resembling the house-fly, but distinctly smaller, being only one-fourth inch long, with a narrower body and proportionately larger wings. It is a grayish color with three dark stripes on the thorax and one Fig. 264.— The cabbage maggot fly (Pegomyia brassiccp. Bouche), female, greatly enlarged. (After Slingerland.) along the middle of the abdomen, and the body bears numerous stiff hairs or bristles. The flies appear just as early cabbage is set out, in late April and early May in New Jersey, and in late May in southern Minnesota. They do not fly far and seem to avoid fields which are swept by the wind. Life History. — The females deposit their eggs on the stem of the plant or in the soil near the stem, at or just beneath the surface of the soil, each female laying some fifty eggs. The eggs are most 316 INSECT PESTS OF FARM, GARDEN AND ORCHARD abundant in late May and early June in central New York. Usu- ally a female lays but one or two eggs on a plant and prefers to lay them in a crevice of the stem or very near it, for if the young mag- gots have to travel far to reach their food, many will die before find- ing it, and if laid on hard soil the maggots will be unable to pene- trate it to the soft tissue of the root, as they are unable to feed on the hard stem above ground. The eggs are about one twenty- fifth inch long, of a pure white color, which renders them easUy seen against the soil by one familiar with them, and are of the shape shown in Fig. 265, having a curious ridge along one side. The eggs hatch in from three to ten days, averaging five to seven. The little maggots at once commence rasping the surface of the tender roots, gradually mine into them, and in three or four weeks have become full grown. The grown maggot is one-third inch long, white or yellowish in color, tapering toward the head and obliquely truncate at the tip of the abdomen. From the head a pair of strong, black, hook-like, rasp- ing jaws project downward, and just back of the head on either side is a minute, light brown, fanlike projection (Fig. 2676), or spiracle, which leads into the breathing system. The oblique posterior end is surrounded by twelve rounded tubercles and in of cabbage the centre are two brownish spiracles (Fig. 267a). maggot, When done feeding the larva burrows one-half to greatly en- . larged; hair one mch under the surface of the soil, and the outer line at center gj^jj^ gradually hardens until it forms a firm brown natural size; shell, called a puparium, within which the larva 6, outline of transforms to a true pupa. Frequently the puparia (After Sling- are found in the galleries made by the maggot or in erland.) crevices of the roots. During the summer this stage lasts about two weeks, but in the fall most of the insects remain in this condition over winter. Thus the whole life cycle from egg to adult requires about six to ten or twelve weeks, according to the temperature and moisture, and the second generation of flies appear in June in New Jersey or by mid-July in southern Minnesota. The maggots of the second generation seem to do but little damage. The life history of the insect during late summer has not been satisfactorily determined, but there is undoubtedly a third genera- tion and in the South, possibly a fourth, the work of the last gen- INSECTS INJURIOUS TO CABBAGE, Etc. 317 eration being sometimes noticed in late cabbage in early fall. On Long Island, N. Y., the larvae have been observed as abund- ant upon cabbage stumps in September and October, working above ground, and the adults and eggs have been common around the adventitious buds. Rough estimates indicate 300 to 1500 maggots per acre on these stumps. The puparia of the last, and in the North possibly some of those of the second generation remain in the soil over winter, though there is some evidence that the flies may also hibernate in the Middle States. Control. — The most effective measures of control consists in cul- tural methods and preventives, but little practical success having attended the use of remedies to kill the maggots. Cultural Methods. — Inasmuch as the puparia remain in the soil or in the old roots or stumps over winter, it is important for this as well as other cabbage pests to gather and destroy all the refuse of the crop as soon as possible and then plow infested land thorough- ly in the fall. Mr. Schoene has shown that by plowing badly in- fested seed-beds six or seven inches deep that only one-fourth as many flies emerged as where '/\ ^X' * the soil was undisturbed. A ro- ' ' '"^ tation of the crop will be of value where cabbages are not grown on large acreages. Cabbage and other cruciferous crops should not be planted after each other, as all are affected by the same pests. It is evident that if the crop is plant- ed at some distance from that of the previous year, and as the flies are known to avoid wind-swept fields, that many of them will not succeed in finding the new planting. As the maggots infest wild mustard and various similar weeds, these should be destroyed as far as* possible and crops affected by the maggots should not be planted on or near land badly infested with such weeds if avoidable. Wild mustard may be readily killed ^ fr' A rA '.V > 9^ Xk ttl^^^ Fig. 266. — Eggs of cabbage maggot at base of stalk. (Photo by Headlee.) 318 INSECT PESTS OF FARM, GARDEN AND ORCHARD by spraying it while young with iron sulfate, 2 pounds to 1 gallon of water. Late-planted cabbage is but slightly affected as compared with that planted earlier. The earliest radishes are often quite free from the pest, those planted later and maturing just as the flies are abundant are badly injured, and the later plantings are free from injury. It is evident, therefore, that where planting of the main crop can be delayed until after most of the flies have oviposited, that it will escape serious injury. Furthermore, either cabbage or rad- ishes may be used as a trap crop, by planting a few rows early and as soon as the flies have laid their eggs on them, plowing them under deeply and then set- ting the main crop. All of these methods involve a familiarity with . _. ^ _ the fly and its eggs which any ob- 5f I ) "^^ servant grower may soon acquire. 0*^^ High fertilization with a quickly Fig. 267.— Cabbage maggot, side available fertilizer will enable the view, enlarged, hair line repre- sents natural size; a, view of plants to make a rapid growth and sTrlcle'blT'if tj-^U "ill be P^fitable even it maggots enlarged. (After Slingerland.) do not OCCUr. Thorough and frequent cultivation while the eggs are being laid destroys many of them. Indeed, one of the best means of control, which is extensively practiced by many growers, is to hill up the earth around the young plants when set, and as soon as eggs are laid, pull the soil containing the eggs away from the plant into the middle of the row, where they or the maggots hatching from them will be killed by the heat. This involves considerable hand work, but where carefully and intelligently followed is one of the surest means of control. Preventives. — Where late cabbage is grown the plants often be- come infested in the seed-bed. To avoid this the seed-beds should be covered with cheesecloth. The sides of the frame are made of 12-inch boards, across which wires are stretched to prevent sag- ging of the cloth, as the whole must be fly-tight. The cover should be removed a week or ten days before transplanting, so that the plants may harden. If eggs are observed in the seed-bed during this time, transplant at once. INSECTS INJURIOUS TO CABBAGE, Etc. 31.9 The most successful preventive yet used consists of a tarred felt card placed around each plant so as to form a collar, lying upon the surface of the soil and thus preventing the fly from depositing her eggs. These cards were originally devised by Professor W. H. Goff, of Wisconsin, and have been extensively used by large growers in that State for many years, as well as in New York, and experiments in New Jersey and Minnesota have proven them very satisfactory. The cards should be made of one-ply tarred felt, as ordinary tarred paper or building paper curls up and is not as effect- ive. The cards are made in a hexagonal shape, with a slit extending from one cor- ner to the centre, which is slit with a star-shaped cut to accommodate the stem. The cards are cut with a tool shown in Fig. 269, which may be made by any blacksmith, and are cut out in rows as illustrated, one cut of the tool making a card. The cards should be placed around the plants when they are set. The earth Fig. 268. should be smoothed down and well firmed by the hand, the card then applied to the plant, and pressed down tight to the ground, so that it fits snugly around the stem and the edges of the slit meet. With a little ex- perience the cards may be applied rapidly, and though involving considerable handwork, the testimony of those who have used them for many years shows that the method is entirely practical and is ^to be preferred to doubtful remedies. A mixture of lime and carbolic acid has recently been used by applying it to the surface of the soil around the plants, so as to form a slight crust, the carbolic acid acting pos- sibly as a repellant. The hme is slaked to a thin cream, and diluted to 3 pints to a gallon of water to which is added a table- spoonful of crude carbolic acid. It is applied liberally to the Cabbage roots destroyed by the cabbage maggot. (After Slingerland.) 320 INSECT PESTS OF FARM, GARDEN AND ORCHARD soil immediately around the plants with a sprinkHng can. This has proven quite effective for cabbage in New Jersey, but in Minnesota cabbage so treated showed but little benefit, though radishes were somewhat protected. Kerosene and sand, gas tar and sand, tobacco dust and many other substances have been used to place around the plant and act as repellants or preven- tives, but all have some objection or have not been sufficiently tested to show their effectiveness and practicability. Dr. J, B. Smith reports, however, that cauliflower-growers at Richfield, N. J., have been using gas tar, 1 part to 25 parts of sand, for several years with good re- sults. Thegas tar costs $1.25 a gallon and will treat 1000 plants. A greater propor- tion of gas tar has proven injurious. Remedies. — For the de- struction of the maggots, both carbolic acid emulsion and hellebore decoction have been extensively used with varying results, but from the evidence so far submitted, the grower would hardly seem warranted in placing much dependence upon them, though where preven- tive measures have been neg- lected, they may aid in reducing the number of maggots and pre- vent a total loss. The surest method of destroying the maggots on the roots is by the use of carbon bisulfide. This is entirely practicable on a few plants, but has not come into general use on a large scale, as no satisfactory tool for its injection into the soil is avail- able. A small hole should be made with a dibble 4 to 6 inches from the infested stem, and a teaspoonful of carbon bisulfide injected and the hole tightly closed with earth. If made too close to the plant the roots will be injured. The fumes kill the maggots by permeat- ing the soil. Where plants are badly infested injection on two sides may be necessary. Fig. 269. — a, tarred felt card in outline one-third size; b, tool for cutting cards, about one-sixth size; c, show- ing how tool is used, dotted line indicating position of edge of tool. (After Goff.) INSECTS INJURIOUS TO CABBAGE, Etc, 321 The Imported Cabbage Worm * Probably the worst pest of the cabbage and one of the best- known garden insects is the common cabbage worm, whose parent ilBrideKw Fig. 270. — The cabbage butterfly {Pontia rapce Linn.): a, larva; b, chrysalis; c, male butterfly; d, female butterfly. (After C. M. Weed.) is the common white butterfly. It is an old European pest and was imported near Quebec, Canada, about 1860, whence it spread * Pontia rapce Linn. Family PieridoB. See F. H. Chittenden, Bulletin 766 , U. S. Dept. Agr. 322 INSECT PESTS OF FARM, GARDEN AND ORCHARD to New England, reached New York in 1868, Cleveland, Ohio, by 1875, and the Gulf States by 1880, and has since spread to all parts of the country. The butterflies are among the first to emerge in early spring. They are white, marked with black near the tip of the fore-wings, which expand nearly 2 inches. The female bears two black spots on each fore-wing, while the male has only one, and both sexes have a black spot on the anterior margin of the hind-wings. Life History. — The butterflies soon commence to lay their eggs on whatever food-plant is available. The larvae feed on all of the common cultivated crucifers as well as many wild sorts, so that the species is never without food. The small yellowish, oval eggs are Fig. 271. — Pteromalus puparum, a chalcis-fly which parasitizes the cabbage worm and many other injurious insects, male and female greatly enlarged — hair line shows natural size. (After Chittenden, U. S. Dept. Agr.) laid on end on the foliage, and are marked with prominent longi- tudinal ridges. They hatch in from four to eight days. The larvsB grow very rapidly, gorging themselves on the foliage, which they skeletonize in their well-known manner, and become full grown in from ten days to two weeks. The mature cabbage worm is about Ij inches long, of a velvety green color, very similar to the fohage, with a faint yellow stripe down the middle of the back and a row of yellow spots on each side. The surface, when seen under a lens, is finely roughened and dotted with small black specks. The chrysalis is attached to the foliage by a strand of silk around the thorax and is first greenish and later light brown in color. The butterflies emerge in from one to two weeks in the summer, but the chrysalides of the last generation in fall hibernate over winter among the old stalks and rubbish on the fields. Thus the whole life cycle in summer requires from three to five weeks. In New INSECTS INJURIOUS TO CABBAGE, Etc. 323 England there are three generations a season and there are prob- ably five or six in the extreme South, as the butterflies there remain on the wing all winter. Enemies. — Fortunately, the parasites of the cabbage worm are becoming very effective in checking its multiplication, and in many sections of New England where it has existed the longest, it rarely becomes very injurious, so well do the parasites control it. Most of these are importations from Europe, one of the most important being a small wasp-like Braconid fly (Apanteles glomeratus Linn.) which was purposely imported from England in 1883. During the autumn of 1904 Dr. Chittenden states that Fig. 272. — Apanteles glomeratus, a parasite of the cabbage worm: a, adult fly; b, cocoon; c, flies escaping from cocoons — natural size, a, h, highly magnified. (After Chittenden, U. S. Dept. Agr.) it killed practically every worm at Washington, D. C. The maggots of these little parasites live within the worms and when full grown come forth and spin masses of small white cocoons on the foliage, often attached to the dead or dying worm (Fig. 272). Another very important parasite is a minute Chalcis-fly (Pteromalus puparum Linn.), about one-sixteenth of an inch long, which was probably imported with its host. These often emerge in immense numbers, hundreds of them often being secured from a single worm. Wasps frequently prey on the caterpillars, using them for provisioning their nests. Various predaceous bugs also attack the worms as well as numerous other internal parasites. CABBAGE The Imported Cabbag^e But-terfly is tKe p arent of the COMMONjn CABBAGE ^ -^ Wutella The cross-s 'iped calibagr worm ^ The looperworm spine a. cocoon In which it changes The Cabbage JLooper is the ^young of a Moth . The but- terflies lay ieire??s mostly an under sides of the cal)ba?e leaves. Theyoun?vOTm5 I hatch from them in. [ 4 to 8 days , feed on the leaves and reach matur- to a pupa before trans- ity in 10 to 1+ daya Then forming to the moth. each attaches itself iy a thread around the body to a leaf, stalk, fence post.orany other 5upport,aiidtransfonnJtoa pupa called a cAr>'J''2''wl^rom this the butterfly emerses In from 7 to 12 days. In northern States there may be three g'enerations during the season and in southernStates five or six. The last chrysalides formed in fall remain thus over winter on dead stalks and produce butterflie s the f ol- lowinj spring". V SPRAY ^ '>r 'With an ^- ARSENICAL in soapy water f^^ j^ij — va^i^^- TomakeSOgallonsofspraydiMolve + llsoflaujy of cabbage dry soap orotScr gooi soap in several saUons of water by boil- woi-m if^j Add this tocncushwatertomaKe SOgallonsThenstir in the arjenical(lHlb3 of poivdcred arsenate of leader J Ihs. of put* form, or other arsenic aJs according to direct ions on p«cKage).Tle soap IS to make the liiju id adhere btller to iKe smooth leaves. To make one gallon of spray use 'A oz of powdered arsenate of Ifad.orloi.of paste form, and an inch cube of soap. DUSTING may be substituted for spraying. usin^lpart of powdered ar3enicalv/ilh4 parts of air-slaked lime. Ji\ small jaff dens the mixture may be shaken on the plants from a cheesecloth bay Apply tKinlywhile thedcw is on the leaves. .,__ COD AN/rr» Since therabba^eheadgrows frominsidetheplant NOT oKKAYtU there is no danger from poisoning If outer leaves are re- moved before cooking sprayins isBafe to within three Result at end of season from severe veeks of harvest U spraying is begun early in llie sea- infestation.yVfcf^ u-ndevehped hcjd son the re will belittle damafe from Jalc broods ofwormi FlQ. 273.— Bureau of Entomology (U. S. Dept. of Agr.) chart showing cabbage worms. 324 INSECTS INJURIOUS TO CABBAGE, Etc. 325 Control. — As the chrysalids pass the winter on the old stumps, foliage, and rubbish on the field, it is evident that they should be destroyed and the field plowed as soon after the crop is removed as possible. A few stalks may well be left standing here and there and be kept well poisoned, so as to act as traps to destroy worms from eggs laid by late female The most effective means of control is spraying or dusting with Paris green or arsenate of lead. The former is used ^ pound to the barrel and the latter 2 to 3 pounds per barrel of water. As the foliage of cabbage is extremely smooth it will be advisable to add 2 or 3 pounds of resin soap or " sticker " to render the material more adhesive. The arsenicals should be applied as soon as the plants are set, and they should be kept well covered until the heads are half formed. If this is done, the young larvae Fig. 274. — The southern cabbage butterfly; a, male; b, female. (After Riley.) will be destroyed before they burrow into the heads, and there will be but little damage after the spraying is stopped. Although there is some prejudice against poisoning cabbage, it is entirely unfounded, for it has been shown that a person would need to eat twenty-eight cabbages at once, if dusted in the ordinary manner, to secure poisonous effects. It is obvious that plants should not have large quantities of dust placed on them after they commence to head, and such applications are entirely unnecessary. Various contact insecticides may be used against the worms on a few plants, but are not practicable for large acreages. Thus water heated to 150° F., will kill all the worms which it hits. Kerosene emulsion will kill the larvae, but must hit them, and may leave an odor on the plant. Pyrethrum or buhach has been used effectively, applying it either dry or diluted with flour, or sprayed as a decoction at the rate of 1 ounce to a gallon of water. Dilute tobacco extract has also proven effective, but 326 INSECT PESTS OF FARM, GARDEN AND ORCHARD .^ Fig. 275. — The southern cabbage butterfly: a, larva; b, pupa. (After Riley.) all of these substances have the disadvantage that they must be brought into actual contact with the worms to kill them. The Southern Cabbage Butterfly * Before the invasion of the imported cabbage worm this species was the cause of considerable injury from the Middle States southward, but it has I / /' (// now been largely replaced and overshadowed in im- portance by the imported species. The male but- terfly is very similar in marking to the female of P. rapoe, and would not be distinguished on the wing. The female is more heavily marked with black, as shown in the figure. The caterpillar is a greenish-blue color with four longitudinal, yellow stripes, and covered with black dots. The habits are very similar to those of the imported cab- bage worm, and the same methods of control should be used. The Potherb Butterfly f This species is more common in the North and East and is distinguished from its near rela- tives by the wings being uniform white without spots. The larvie are very similar to those of the imported species and the habits are very similar. Like the south- ern species, though formerly very common and often injurious, this species is now rarely common enough to do much iniury and Fig. 276.— The potherb butterfly feeds mostly on wild plants. The and caterpillar. (After Harris.) same remedies as for the imported species should be used. * Pontia protodice Boisd. Family PieridcB. t Pontia napi Linn. Family Pierida;. INSECTS INJURIOUS TO CABBAGE, Etc. 327 The Cabbage Looper * Next to the imported cabbage worm the looper is probably the most serious pest of cabbage and closely resembles it in the way it strips the foliage.f The name " looper " is derived from its " looping " habit of walking like a measuring worm, due to the absence of legs on the third and fourth abdominal segments. The larvse are pale to dark green in color, marked with several longitudinal white lines, as shown in Fig. 277, which become obscure as they become full grown, so that they might be easily mistaken for the com- mon cabbage worms were it not for the looping gait. The species occurs throughout the ter- ritory east of the Rockies, but is much more commonly in- jurious in the Middle and Southern States. Although cabbage and cauliflower are the fa- vorite food plants, it attacks all of the cru- ciferous crops, is fre- quently injurious to lettuce, peas, celery and beets, and has Fig. 277 — The cabbage looper (Aidogmpha bras- u^^v, f^,,r..i iiv^^v, r,n,'fQ sicoe Riley): a, male moth; b, egg from above been found upon quite ^^^^ from side; c, full grown larva in natural a list of cultivated position feeding; d, pupa in cocoon — a, c, d, ^^r.^c cr^A TTQr-i'rMic one-tliifd larger than natural size, 6, more crops and various g^^i^^ged. (After Howard and Chittenden, weeds. U. S. Dept. Agr.) Life History. — The life history has not been carefully observed, but it seems probable that the winter is passed in the pupa stage in the old leaves, stumps and rubbish of the cabbage field. Sirrine * Autographa brassicoe Riley. Family Noctuidoe. See F. H. Chittenden, Bulletin 33, n. s., Div. Ent., U. S Dept. Agr.; F. A Sirrine Bulletin 144, N. Y. Agr. Exp. Sta. t See also page 324 328 INSECT PESTS OF FARM, GARDEN AND ORCHARD states that the life history is similar to that of the imported cabbage worm, and it seems probable that there are three genera- tions a year in the Middle States, and possibly more farther South. Injury to cabbage seems to be worse in late summer. When full grown the larva spins a very thin, transparent, white cocoon, attached to the leaf upon which it has been feeding and in it transforms to the light-brown pupa. The pupal stage varies from a week in midsummer to three weeks in October, and the pupse of the last brood hibernate over winter. The moth has a wing expanse of about Ij inches, and the fore- wings are grayish-brown mot- tled with gray, whitish, and blackish, as shown in Figs 277, 278. Just inside of the centre of the fore-wings is a characteristic white spot. The hind-wings are paler brown, with the outer border darker, and the margins of both wings are strongly scalloped. Control. — The same general methods as advised for the im- ported cabbage worm will effect the control of this spe- cies. Sirrine states that dust- ing the plants with Paris green has not proved satisfactory, but found the use of Paris green with the resin soap stick- er to be very effective. Arsen- ate of lead is more adhesive and is therefore superior for cabbage but will be improved by the addition of the "sticker." Fig. 278. — The cabbage looper moth at rest from side and from above — natural size. The Diamond-back Moth * The larvse of the imported diamond-back moth or cabbage plutella are commonly found on cabbage wherever it is grown * Plutella maculipennis Curtis. Family Tineidoe. INSECTS INJURIOUS TO CABBAGE, Etc. 329 and as a rule do but little injury, though occasionally they be- come troublesome. " The larvae when full grown measures three-tenths inch in length, tapers a little to the extremities, and is of a pale green color. It is active and irritable, in this respect being very different from any of the larger larvae described." The wings of the parent moth " are kept folded against the sides of the body, are a little turned up at the tips, and are provided with a long fringe. The color above on the head, thorax, and upper part of the closed wings is a light clay-yellow. That part of the wings that is lowest when they are folded is bronze brown, this color terminating abruptly where it meets the clay-yellow of the back by a well-defined sinuous margin. The length from the front of the head to the tip of the folded wings is about one- fourth inch."* " The eggs are whit- ish, very minute, and are attached to the leaves, though some- times when very abun- dant they are, it is said, placed on the sides of crates holding cab- bage." The full-grown larvae pupate in small cocoons composed of a delicate lace-work of silken threads through which the whitish, often brown-striped, pupa may be seen. In winter the cocoons containing pupae are found on old cabbage stalks in the field or on stored cabbage. Two or three genera- tions a year occur in the more northern states and four or five generations farther south, while in the extreme South it may be found active practically throughout the year. The species has a world-wide distribution. " During very dry weather these little insects become exceed- ingly common, and riddle the cabbage leaves with small holes. Wet weather, on the other hand, has long been known to be * H. Garman, Bulletin 114, Ky. Agr. Exp. Sta., p. 29. Fig. 27P. — The cabbage plutella or diamond- back moth (Plutella macidipennis Curtis) : a, larva; b, segment of same greatly enlarged; d, pupa; e, pupa in cocoon; /, adult moth; g, wings of dark variety; h, moth with wings folded. (After Riley^ U. S. Dept. Agr.) 330 INSECT PESTS OF FARM, GARDEN AND ORCHARD unfavorable to them," and drenching the plants with water has been recommended as one of the best means of control. The same remedies applied for the other cabbage worms will readily control this little pest. Fig. 280. — The harlequin cabbage bug {Murgantia histrionica Hahn.): a, eggs — enlarged; h, nymphs, more enlarged; d, adults seen from above and below — enlarged; e, head and beak of same; /, parasite of eggs — enlarged; bugs and eggs (a) on leaf, natural size. (After W. G. Johnson.) The Harlequin Cabbage-bug * Southern truckers have been familiar with the harlequin cabbage-bug, " calico-back," " terrapin-bug," or " fire-bug," as * Murgantia histrionica Hahn. Family Pentaiomidoe. See F. H. Chitten- den, Farmers' Bulletin 1061, U. S. Dept. Agr.; R. I. Smith, Journal Economic Entomology, Vol. II, p. 108, and F. B. Paddock, Bulletin 179, Texas Agr. Expt. Station. INSECTS INJURIOUS TO CABBAGE, Etc. 331 it is variously called, for the past generation. A native of Mexico and Central America, it migrated into Texas about 1864 and then spread eastward along the Gulf Coast, and northward until it reached Maryland and Virginia, about 1880, New Jersey in the early 90's, and up the Mississippi Valley to southern Ohio and Indiana by 1890. On the Pacific Coast it is found in southern California and Nevada. Although it spread to Long Island, N. Y., southern Pennsylvania, and northern Ohio, and Indiana, its advance was checked by the cold winters of the late Fig. 2Sl, — Field of caliiiage in l)(>l:i\vare ruined l)y the liarl('c|uiii Inig. 90's and it will probably never become very injurious north of the Potomac and Ohio rivers. The appearance of the gayly colored bugs, shining black or deep blue, marked with brilliant red or orange, as shown in Fig. 280, is so distinctive that they are readily recognized, and gives them the name of harlequin-bug or calico-back. They are about one-half inch long, flattened, and the general shape and markings have given them the local name of " terrapin bug." The bugs suck the sap from the leaves of cabbage and other crucifers, the plants wilting and dying, and turning black as if 332 INSECT PESTS OF FARM, GARDEN AND ORCHARD they had been swept by fire; hence the name " fire-bug." A half-dozen of the adult bugs will destroy a small plant in a day or two, and as they frequently appear in enormous numbers and as they multiply rapidly, unless they are fought vigorously they will soon destroy a large patch of cabbage. Life History. — The adults hibernate over winter in old cabbage stumps and under the leaves and other rubbish left on the field, and emerge early the next spring. In South Texas they may be found at work nearly all winter, being common in February and March; in North Carolina they appear about April 1st, and in Maryland about May 1st. The eggs of the first generation are deposited mostly on kale, wild mustard or other wild cruciferse, each female laying about 100. They are placed in a double row of about a dozen and are white, marked with two black bands and a small spot, which makes them look like small white barrels with black hoops. The eggs of the spring generation hatch in about ten days, and the nymphs feed upon the cabbage for from six to nine weeks before becoming full grown in North Carolina and the District of Columbia, while in the Gulf States the eggs hatch in four to eight days and the nymphs become full grown in three or four weeks, the development of these stages being determined by the temperature. The nymphs are much like the adults in coloration, though differently marked and lacking wings. They molt five times, some of the different stages being shown in the figure. From North Carolina northward there seem to be but three generations of the insect. The summer generation develops more rapidly, the eggs hatching in four or five days, but the fall generation requires about the same time as in spring. In midsummer the whole life cycle may be passed in about two weeks in the Gulf States, according to various author- ities, so that there may be a half dozen generations, though the exact life history does not seem to have been observed there. Control. — This is an exceedingly difficult pest to combat after it has become numerous in the cabbage patch, so that every effort should be made to prevent its appearance. As it hibernates under old stalks and leaves it is obvious that they should be cleaned up and the field plowed as soon as the crop is harvested. By leaving a few piles of stalks, leaves and rubbish, the bugs might be concen- trated and then destroyed. INSECTS INJURIOUS TO CABBAGE, Etc. 333 The most successful method of control yet devised is the use of a trap-crop, to which the bugs are lured as they emerge from hibernation and on which they may be destroyed before they attack the cabbage. Kale planted in the fall or mustard planted early in the spring serves well for a catch crop, and should be planted in rows through the intended cabbage-field. The bugs seem to prefer the kale to the young cabbage, and while concen- trated upon it they should be killed by spraying them with pure kerosene. The trap-crop may well be planted at different dates, so that after one row has been destroyed by spraying, another will invite the remaining bugs. The nymphs may be destroyed by spraying them with 15 per cent kerosene emulsion or whale-oil soap, one-half pound per gallon. Whale-oil soap used at the rate of 1 to 2 pounds to the gallon will kill most of the adult bugs hit by it without injury to the cabbage, but dependence should not be placed upon control by spraying, as its practicability on a large scale is yet to be demonstrated. The Cabbage-aphis * Wherever cabbage is grown the common " cabbage-louse " occasionally becomes abundant enough to do serious damage, often destroying young plants, which become covered with the disgusting masses of grayish aphids. They are found commonly in almost every cabbage-patch, but usually their natural enemies are so effective as to prevent their increase; otherwise they would be one of the most serious pests of cruciferous crops. They may be found on all of the cultivated and wild cruciferse, but cabbages and turnips are injured worst, serious damage often being done to turnips in the South. " The wingless viviparous female has a rather long oval body, covered with a whitish mealy coat. When this coat has been removed . . . the body is seen to be a grayish-green color, with eight black spots down either side of the back, increasing in size toward the posterior end. The antennas are green with black tips, and are shorter than the body, and the eyes, legs and tail are * Aphis brassicoe Linn. Family Aphididoe. See C V. Riley, Report of U. S. Commissioner of Agriculture, 1884, p. 317. C. M. Weed, "Insect Life," Vol. Ill, p. 289. G. W. Herrick, Bulletin 300, Cornell Univ. Expt. Station. F. H. Chittenden and C. H. Popenoe, Bulletin 2, Va. Truck Exp. Sta., p. 22. 334 INSECT PESTS OF FARM, GARDEN AND ORCHARD black. The young when first hatched are oval, shining, bright yellow in color, and lack the mealy coat. The winged viviparous female is yellowish-green, with the eyes, neck and thoracic lobes black, and the antennae and nectaries dark brown. The legs are dusky brown and hairy; the tail is dark green or brown and also hairy; the wings are rather short, with stout coarse veins and dark stigma." (Riley). Life History. — Though the cabbage-aphis is an old European species and was observed in this country as early as the latter part of the eighteenth century, its life history has only recently been carefully worked out by Professor G. W. Herrick and Mr. J. W. Hungate of Cornell University (I.e.), from whose account the fol- lowing is taken: The oviparous females appear in the fall and are fertilized by the males, and deposit their eggs in large num- bers on the leaves of the cabbage, during October and the first days of November, in central New York. The eggs are laid on rape, turnip, brussels sprouts and kohl-rabi but are most abundant on cabbage, particularly in the crevices and depressions of the under surfaces of the leaves. On leaves taken at random from a badly infested patch, from 177 to 293 eggs were found on a leaf. Two to three eggs are laid by each oviparous female. When first laid the eggs are a yellowish-green, but soon turn a shining black. From eggs taken at random and left under normal outdoor conditions, 76 per cent hatched the next spring, while all eggs hatched which were laid by females known to have been fertilized. Eggs hatched about April 1, 1910, in central New York, the season being an early one. From the stem mothers which hatched from these eggs, twenty- one generations of wingless females were reared up to December 3, 1910, the average length of a generation being about twelve days. During the summer generations of winged females are produced, especially on crowded plants, and these serve to spread the pest to Fig. 282. — ^The cabbage-aphis {Aphis brassicoe Linn.) : o,vvinged form; b, wingless viviparous female — greatly enlarged. (After Curtis.) INSECTS INJURIOUS TO CABBAGE, Etc. 335 unaffected plants. The wingless females become full grown in about thirteen days during the summer and live for about forty -six days, during which time they will give birth to an average of forty- one young, producing as high as six young in a day. The winged forms are much shorter lived, living only about ten days and giving birth to but from seven to thirteen young. There is no question that in the Southern States the viviparous females may continue to reproduce all winter, and it is quite prob- able that some of them survive in pits and cellars in the North, where eggs also probably occur. Thus Sirrine* states that it ** is certain that this aphid can survive the winter on cabbage stored in cellars or pits, also that cabbage stored in pits for seed purposes furnishes the supply of aphids for infesting the seed stalks in early spring." This being the case it should be an easy matter to de- stroy the aphids by fumigation before removing them from the pits. Control. — From the habits outlined it is evident that, as for other cabbage pests, the refuse of the crop should be cleared up and destroyed in the fall. Any of the standard contact insecticides, such as kerosene emulsion, 1 part stock solution to 15 parts of water, whale-oil soap, 1 pound to 6 gallons, or " Black-leaf 40,' ' 1 part to 800 of water, will destroy the aphids, but the spray- ing must be thorough, as the waxy coating serves to protect them. According to Professor Franklin Sherman, any good laundry soap used at the rate of 1 pound dissolved in 3 gallons of water, will destroy the aphids. Where water under pressure is available in a small garden, the aphids may be held in check by washing them from the plants with a strong stream from a garden hose. Plants infested in the seed-bed may be freed from the aphis by dipping in whale-oil soap solution, 1 part to 8 of water. Fortunately for the grower, the cabbage-aphis is usually held in check by numerous parasitic enemies, principally little wasp- like flies of the family Braconidce, and by several species of lady- bird-beetles and syrphus-fly larvae, which will often destroy a colony within a few days. The Spinach-aphis or Green Peach-aphis f Another species of aphis often becomes destructive to cabbage, spinach, celery and lettuce, as well as various greenhouse crops, \F. A. Sirrine, Bulletin 83, N. Y. Agr. Exp. Sta., p. 675. t Myzus 'persiccB Sulz. 336 INSECT PESTS OF FARM, GARDEN AND ORCHARD In the fall it migrates to peach, and is also known as the green peach-aphis, as which it is discussed on page 587 The Turnip Louse * The turnip louse, also called the false cabbage aphis has recently- been recognized as a separate pest of crops of this group. It is rather southern in its damage but extends over a large part of Fig. 283.— The spinach-aphis (Myzus persicoe Sulz.): which often becomes a cabbage pest: a, winged adult; b, young nymph; c, older nymph; d, last stage of nymph — all greatly enlarged. (After Chittenden, U. S. Dept. Agr.) the country. Mr. Paddock's excellent summary of the insect according to his observations in Texas, is given here verbatim: " A new species of plant louse, commonly called the turnip louse, and not the cabbage louse, as was formerly supposed, does the damage to the fall turnips and winter truck. This damage is general over the entire State of Texas. Not only do the truck * Aphis pseudobrassicce Davis. See J. J. Davis, Bulletin 185, Purdue Univ. Expt. Station; and F. B Paddock, Bulletin 180, Texas Agr. Expt. Station. INSECTS INJURIOUS TO CABBAGE, Etc. 837 regions suffer, but every home garden is damaged by the turnip louse. The food plants of the turnip louse are turnips, cabbage, mustard, cauliflower, kale, rutabaga and rape. The normal form of reproduction of the turnip louse in Texas is asexual throughout the year. Observations have been made upon this louse in Texas from Brownsville, on the 26th parallel, to Wichita Falls, on the 34th parallel. True hibernation does not take place in Texas, even at the northernmost point of occurrence the lice reproduce some during the winter. The summer is the critical period in the life history of the turnip louse, as it is forced to sheltered locations and none of the cultivated^ host plants are grown at that time of the year. Thirty-five gen- erations of the lice were reared in pot cages in one year. Two other species of plant life are often found closely associated with the turnip louse. These are the "garden aphis " and the cabbage louse. The natural factors, of control of the turnip louse are widespread over the State. Two species of parasites, Dia- eretus rayae Curt., and LysivUehus ""'^^^It^^^l-^^Z^ tZ^. testaceipes Cress., have been commonly (After Paddock.) found, the former at College Station and the latter in other sections. Three species of lady beetles have been observed to feed freely on the turnip louse. These are Hippodamia convergens Guer., Megilla maculata DeG., and Coccinella munda Say. Syrphid flies and lace-wing flies are usually found in limited numbers where the turnip lice are abundant. A fungous disease was very destructive to the turnip louse during the season of 1914 at College Station. For the artificial control of the turnip louse, spraying is the most satisfactory method. Of the materials which can be used for spray- ing, laundry soap solution gives as satisfactory results as any and is easily obtainable. The secret of success in the control of the turnip louse is the use of the 45° elbow and an " angle " type spray nozzle. 338 INSECT PESTS OF FARM, GARDEN AND ORCHARD By the use of these it is possible to direct the spray on the under sides of the leaves, where the lice feed. The preventive measures against the turnip louse are rotation, proper planting time, trap crops, clean culture, and the destruction of the first colonies." Flea-beetles * A considerable number of small flea-beetles attack cabbage and other cruciferous crops, and although as a rule only troublesome, they appear periodically in enormous numbers and do serious injury. They are mostly small species (there being seven species of the genus Phyllotreta alone) not over an eighth of an inch long. One of the most 'common throughout the country is the striped turnip flea-beetle.f It is polished black with each wing-cover marked with a broad, wavy band of pale yellow. The microscopic white eggs are laid in a little excavation of the root near the crown of the plant. The larvae mine into the roots and have been reported to do considerable injury to them, but it seems probable that most of them live upon the roots of cruciferous weeds. The full grown larva (Fig. 285a), is about three-eighths inch long, quite slender and tapering, yellowish white, with brown head and anal plate, and with marks on the thorax and transverse rows of minute hair-bearing tubercles as shown in the figure. The West- ern cabbage flea-beetle J is the more common from the Dakotas southward to Mexico and westward to southern California. It is a uniform deep olive-green, with the surface irregularly punctate, and 7-100 inch long. Another species almost indistinguishable from the first species above, is the wavy-striped flea-beetle, § whose larvae mine in the leaves of wild pepper grass {Lepidium virginicum), and is most abundant in the Middle and Southern States. The life history has been fully described by Dr. Riley (I.e.). Control. — Where the plants are sprayed for the cabbage worms with Paris green or arsenate of lead, there will probably be little trouble with flea-beetles. Otherwise, spray with arsenate of lead; 3 to 5 pounds per barrel, or Paris green one-third to one-half pound, adding the resin soap or " sticker," so as to give the * Family Chrysomelidoe. Refer to pages 266, 303, for other flea-beetles* See C. V. Riley, Report U. S. Commissioner Agr., for 1884, pp. 301-308. t Phyllotreta vittata Fab. X Phyllotreta pusilla Horn. § Phyllotreta sinuata Steph. {zimmermani Crotch.) INSECTS INJURIOUS TO CABBAGE, Etc. 339 foliage a good thick coating, for the spray probably acts fully as much as a repellant as a remedy. Where injury is antici- pated it will be well to dip the plants in arsenate of lead 1 pound to 10 gallons of water when planting them. By thoroughly dust- ing the plants with lime, land plaster, strong tobacco dust, dilute pyrethrum, or any of the dusts commonly used for such insects. FiG.^285. — The striped turnip flea- Fig. 286. — The western cabbage flea- beetle (JPhyllotreta vittataYah.): beetle — much enlarged. (After Riley, a, larva; h, adult — greatly en- U. S. Dept. Agr.) larged. (After Riley, U. S. Dept. Agr.) applying the dust in the early morning while the dew is on the plants, they may be protected from attack as long as they are kept thoroughly covered. It is evident that the weeds upon which these pests develop in the larval stage should be destroyed. Where plants are attacked in the seed-bed, screening as advised for the root-maggot will prevent injury. Cloth with from 20 to 30 threads to the inch has proven most satisfactory for the screens, which should be applied early and be made perfectly tight. CHAPTER XVIII INSECTS INJURIOUS TO MELONS, CUCUMBERS, SQUASH, ETC.* The StripOd Cucumber-beetle f Just as the httle cucumber and melon plants appear above the soil they are attacked by hordes of hungry black-and-yellow-striped beetles, which feed ravenously upon the succulent seed- leaves, often killing them entirely so that reseeding is neces- sary. This little striped beetle, often known as the "striped-bug "or "melon-bug," is well known to all growers of cucurbs Fig. 287.— The striped cucumber -beetle (Diabrotica east of the Rocky vittata Fab.): a, beetle; b, larva; c, pupa; d, egg; e, Mountains and sculpture of egg — a, b, c, much enlarged, d, more ' enlarged; e,highly magnified. (After Chittenden, also OCCUrs in S. Dept. Agr.) Washmgton. The beetle is about two-fifths inch long and half as wide, of a bright yellow color with a black head and three black stripes on the wing-covers. Life History. — The beetles hibernate over winter in the ground where they have been feeding the previous fall, or along the edge of woodlands, or wherever suitable shelter is obtained, and emerge in the spring two or three weeks before cucurbs are planted. At * See A. L. Quaintance, Bulletin 45, Geo. Agr. Exp. Sta.; J. B. Smith, Bulletin 94, N. J. Agr. Exp. Sta.; R. I. Smith, Bulletins 205 and 214, No. Car. Agr. Exp. Sta. t Diabrotica vittata Fab. Family Chrysomelidre. See F. H. Chittenden, Farmers' Bulletin, 1038, U.S. Dept. Agr.; T. J. Headlee, 20th Report N. H. Agr. Exp. Sta., p. 499. 340 INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. 341 this season they seem to feed on ahnost anything, as they have been observed feeding on a long hst of food-plants, frequent- ing flowers whose petals are eaten. As soon as squash, melons, or cucumbers break through the soil, they gather upon them and refuse all other food. If the foliage is covered with any offensive substance they will seek out spots which have not been reached and feed upon them, which fact is of im- portance in considering remedies. After feeding upon cucurbs for a few days the beetles pair and the females commence to deposit eggs. The eggs are deposited singly and are merely dropped in crev- ices of the soil or in the opening around the stem of the plant. The egg is oval, about one-fortieth inch long, bright yel- low, and sculptured with microscopic hexagonal pits. A female lays about one hundred eggs during a period of a month, and they hatch in about eight days at a mean temperature of 74° F. The larva is a slender, white, worm-like grub, about three-tenths inch long, with dark-brown head and anal-plate, and lighter brown thorax. The larvae bore into the roots, often tunneling into the base of the stem, and sometimes mine into melons lying on damp soil. Rarely does injury by the larvae become noticeable, though we have observed whole patches of cucumber and melon vines killed by them, which seems remarkable, considering the immense numbers of the beetles which must give rise to many times more larvae. The larva becomes full grown in about a month and then forms a delicate earthen cell just below the surface of the soil and in it transforms to the whitish pupa, from which the beetle emerges in from one to two weeks, according to the temperature. In southern New Hampshire the beetles emerge from the last of August to the first of October, the complete life cycle requiring from seven to nine weeks, there being but one generation a year, and this seems to be true in New York. In Kentucky the complete cycle requires but thirty-nine days, and in the District of Columbia newly emerged Fig. 288. — Larva of strip- ed cucumber beetle at work in cucumber stem. (Photo by Headlee.) 342 INSECT PESTS OF FARM, GARDEN AND ORCHARD beetles are found by mid-July, so that there are undoubtedly two generations in that latitude, as the l)eetles have been found pairing and with well-developed eggs in Delaware, August 1st. In the latter part of the season the beetles feed on the blossoms and pollen, particularly of squash, rarely touching the foliage. With the first frosty nights they seek sheUer under the fallen leaves and enter hibernation with the first killing frosts. Control. — For a few plants or where the beetles are unusually abundant, coverings of netting have long been used to protect the plants. A barrel hoop cut in two, crossed, and the ends fastened to another hoop, and the whole then covered with netting, makes an admirable cover, often sold by dealers. Two stout wires bent into arches and crossed, may also be covered with netting, the lower edge of which is held by earth packed over the edges. Or cone-shaped covers may be fashioned out of wire screen- ing and kept from year to cucurbs. (After Headlee.) ' y^^^.^ (SeeHeadlee, I.e.) Many growers obviate loss of plants and the necessity of replanting by sowing the seed in rows rather thickly and then thinning out to the desired distance after the worst injury by the beetle is passed. Others make several plantings in each hill at intervals of a week, but the former plan will ensure earlier growth. The growing of rows of early beans to act as a trap-crop has been suggested, as the beetles will gather on them, it is said, and having an abundance of food will not injure the cucurbits. Squash may be effectively used in this way as the beetles are peculiarly fond of the quick-growing squash seedlings. A week or ten days before the regular crop, plant rows of squash seed around and through the prospective field, and plant more rows when the regu- lar crop is planted. If the main crop be kept well dusted or sprayed as advised below, the beetles will concentrate on the trap- Fig. 289. — ^Wire screen cover for young INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. 343 squash and might be destroyed upon it by spraying with pure kerosene. Liberal fertihzation with quick-acting fertihzers will aid the young plants to make a quick growth and thus outgrow the injury. Growers have long known that if the plants are kept thoroughly covered with some sort of dust that the beetles will not molest them, and various sprays have been used in the same way. To be effective, the plants must be dusted in early morning while the dew is on and all parts of the plant, above and below, must be thoroughly covered. This must be repeated as often as the dust is washed or blown off, or the plant outgrows it. Air-slaked lime mixed with sulfur, tobacco dust, and bug-death have been the most effective, though similar powders will be found beneficial. Bor- deaux mixture has been recommended for this purpose, but seems to have a stunting effect on the young plants. The most valuable repellant seems to be a spray of arsenate of lead 3 to 5 pounds per barrel. This not only repels the beetles better than any other substance tested by Dr. Headlee but also kills many which are forced to feed upon it. Arsenite of lime and zinc arsenite are both recommended by Dr. Chittenden, (I.e.) to be used as is the lead arsenate, either with or without Bordeaux mixture. Most evidence now available indicates that these poisons will pro- tect the vines to a rather limited extent and too much reliance must not be placed upon them. They are of value when used in connection with the cultural methods outlined. The problem of cucumber beetle control is one which needs more investigation, in spite of the fact that the insect has long been known. Various repellants, such as kerosene, turpentine, naphthalene or moth balls, and other similar odoriferous substances, have been strongly recommended, but careful tests have not demon- strated their efficiency. It is evident that the cleaning up of vines as soon as the crop can be gathered and the destruction of all refuse will deprive the beetles of food in the fall and force them to seek other hibernating places, thus increasing the mortality. The spotted cucumber-beetle, Diabrotica 12-punctata Oliv., is found almost always with the striped beetle and injures the plants in the same way. A full account of it will be found in the chapter dealing with insects affecting the corn plant. 344 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Melon-aphis * Just as the vines commence to run, a plant will be found here and there with the foliage curled up and wilting and within will be found masses of the greenish " melon lice," which have caused the injury by their many beaks sucking out the sap of the plant. If allowed to multiply unchecked and their natural enemies do not prevent their increase, they will sometimes become so abundant Fig 290. — The melon aphis (Aphis gossypii Glov.): a, winged female; aa,, enlarged antenna of same; ab, dark female, side view, sucking juice from leaf; b, young nymph; c, last stage of nymph of winged form; d, wingless female — greatly enlarged. (After Chittenden, U. S. Dept. Agr.) as to completely ruin a whole crop just as the melons are com- mencing to ripen. It is one of the worst pests of cucurbs and one which requires constant vigilance on the part of the grower. The aphids are to be found on various weeds in early spring and appear on cucurbs soon after they start growth. Both winged and wingless females occur throughout the year. The wingless * Aphis gossypii Glover. Family Aphididce. See F. H. Chittenden, Farmers' Bulletin 914, U. S. Dept. Agr. ; also C E. Sanborn, Bulletin 98, Oklahoma Agr. Exp. Sta., and C. E. Dursh, Bulletin 174, Illinois Agr. Exp. Sta. INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. 345 form is about one-fifteenth inch long and varies from light yellow or tan colored to deep olive-green or deep green which appears almost blackish, the abdomen being always more or less mottled. The rather long, tapering honey-tubes are jet-black, and the legs and antennse pale whitish-yellow. The young nymphs always show a distinct yellowish-brown or pale salmon-colored area just in front of the honey-tubes and a dark transverse band between them. The nymphs of the last stage, in which the wing pads are visible, are marked on the back with little flecks of silvery white, waxy bloom. The winged female is about the same length and the wings expand one-fifth to one-quarter inch. The color varies as in the wingless form, but there are black spots along the sides of the abdomen, and the head and thorax are dark as shown in the above figure. The melon-aphis is found throughout the country southward through Central America, and though it often does serious damage in the North it is worse in the South. It has a long list of food plants, among the crops injured by it being all the cucurbs, cotton, okra, orange, and its occasional food-plants include many others, as it is found on a long list of weeds, most abundantly on shep- herd's purse and pepper-grass, upon which it multiplies in early spring and probably passes the winter. Life History. — The life history is much the same as that of most of our common aphids, though of some phases we are still in ignorance in spite of the most careful study. The females give birth to from four to ten aphids a day, depending upon the tem- perature and food supply, and these become full grown in from six to eight days. As the affected leaf becomes non-succulent the aphids migrate to another leaf and often cluster on the terminal which is checked and stunted. As they become more numerous, winged forms migrate to other plants and within two weeks a colony of fift}^ or more will form the progeny of every one born by the immigrating female. Reproduction seems to go on this way throughout the year, being stopped only by the cold of win- ter, as far as has been observed. No true sexual forms or eggs, as are known to occur with other nearly related species, have been observed, and the viviparous forms have been found throughout the winter in Colorado and Texas. 346 INSECT PESTS OF FARM, GARDEN AND ORCHARD Enemies. — Fortunately the melon-aphis is subject to the unre- mitting attack of many insect enemies, the list including some thirty-five species. Among the more important are the common Fig. 291. — Melon aphids on cotton leaf which have been killed by parasites. INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. 347 ladybird-beetles and their larvae, of which the convergent lady- bird,* the nine-spotted ladybird, f and the spotted ladybird, t shown in Figs 1-5, are among the most effective, and the maggots of various common syrphiis-flies, and the aphis-hons.§ Even more beneficial are the little parasitic flies whose larvae live within the maggots and destroy myriads of them with incredible swift- ness. The most common of these H are the same as the most common parasite of the green bug (Fig 120), and they often destroy the aphids over a whole field in a few days. They are most effect- ive in bright, warm weather, when they reproduce most rapidly, but in cool, moist weather they reproduce but slowly, and if such a summer follows similar weather conditions during the spring, the aphids multiply rapidly without a corresponding increase of their enemies and serious damage results. Inasmuch as these same enemies attack the cabbage-aphis, Professor C. E. Sanborn* has suggested that the cabbage-aphis might be encouraged to multiply on crops planted near melons or cucumbers, so that an abundance of parasites and insect enemies might be in readiness to attack the melon-aphis when it appears. This might be done by planting kale, rape, or wild mustard in the fall, upon which the cabbage- aphids will pass the winter and will multiply in early spring. This trap crop should be planted in rows around the prospective melon-field, and if the latter be large, rows should be planted through it. If the kale does not soon become infested with the cabbage-aphis, transport some from the nearest cabbage-patch. The ladybirds and parasites multiply rapidly with plenty of the cabbage-aphids for food, and as soon as the food supply becomes scarce they are forced to migrate and will search out any colonies of melon-aphids. This method has not come into general use. Control. — The most important factor in the control of this, as well as many other aphids, is constant watchfulness, inspect- ing the plants frequently and destroying badly infested individual plants and treating small areas before the pest becomes spread throughout the crop. * Hippodarnia convergens Guer. t Coccinella 9-notata Herbst. X Megilla maculata DeG. Family Coccinellidce. § Family Chrysopidce. ^ Lysiphlebus testaceipes Cress. Family Braconidoe. * See Bulletin 89, Texas Agr. Exp. Sta., p. 44. 348 INSECT PESTS OF FARM, GARDEN AND ORCHARD Where a few young plants are affected or before the leaves have become badly curled, the aphids may be destroyed by spraying with kerosene emulsion, containing 5 to 8 per cent kerosene, whale-oil soap, 1 pound to 5 gallons of water, or tobacco extracts, the latter having given best results in recent tests. Emulsion must be carefully made or burning will result. The aphids must be hit to destroy them, and it is necessary to use an underspray nozzle (page 73), or to turn the vines over and then return them, so that all the insects may be covered. After the foliage is well curled it is practically impossible to reach the aphids by spraying. Fumigation with carbon bisulphide and tobacco preparations has been extensively tested and recommended. It has not been found practical on a large scale and there has been some tendency to injure the plants in the process, both by the action of the fumes and by the handling necessary to get the larger vines under the fumigating frames. For this reason it is now considered of doubtful value under any circumstances and is not recommended. If the vines are watched carefully and sprayed with " Black- leaf 40 " at the first appearance of the plant-lice, the matter of control will be found to be relatively simple, and this, along with the cultural methods suggested, is the only treatment that will be found practical for the growers generally. Other spray solutions, or mixtures such as kerosene emulsion or whale-oil soap, may, of course, be substituted for the tobacco with about the same results. The Squash-bug * About the time the vines begin to run a wilted leaf is found here and there which examination shows to be due to the common brownish-black squash-bug. If search be made in early morning, the bugs will usually be found secreted under clods of earth, or whatever rubbish may be near the vines. They are about three- quarters inch long, and too well-known to need other description. Life History. — For the next month or six weeks the females deposit their eggs, mostly on the under sides of the leaves. They are oval, about one-sixteenth inch long, laid in irregularly shaped clusters. When newly laid they are pale yellow-brown, * Anasa tristis DeG. Family CoreidcB. See Weed and Conradi, Bulletin 89, N. H. Agr. Exp. Sta.; F. H. Chittenden, Circular 39, Div. Ent., U. S. Dept. Agr. Fig. 292.^ — Squash-bugs and nymphs at work on young plaui — niuural size. 349 350 INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. but this soon grows darker, so that the stage of their development may be told by the color. In from six to fifteen days, depending upon the temperature, the eggs hatch. The young nymphs are brilliantly col- ored, the antennse and legs being bright crimson, the head and anterior thorax a lighter crimson, and the pos- terior thorax and abdomen a bright green, but in a little while the crimson changes to a jet black. The young bugs remain near each other, suck- ing the juices from the foli- age and soon causing the leaves to wither. During their growth, which requires four to five weeks, they moult some five times. The adult bugs appear in August, but in the North they neither mate nor lay eggs that season, but feed until frosts blacken the leaves, when they disappear into winter Fig. 293. — Eggs of the sq\iash-bug — en- larged. (Photo by R. I. Smith.) Fig. 294. — The squash-bug; a, ma- ture female; b, side view of head showing beak; c, abdominal seg- ments of male; d, same of female; a, twice natural size; b, c, d, more enlarged. (After Chittenden, U. S. Dept. Agr.) Fig. 295. — The squash-bug: adult at left, and different stages of nymphs — about 13^ times natural size. (Photo by Quaintance.) INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. 351 quarters, hibernating along the edge of woodlands, beneath leaves, under logs, boards or whatever shelter may be available. In the South there are probably two or three broods a year accord- ing to the latitude. Control. — The eggs are easily seen and should be picked off and destroyed. The adults cannot be killed by insecticides, but the nymphs may be destroyed by spraying with kerosene emulsion, or a mixture of " Black-leaf 40, " one to 400 with soap. The adult bugs may be readily trapped by placing small pieces of board or similar shelter near the vines, under which they will hide at night and from which they may be gathered in the early morning. Cucumbers and melons may be protected by planting early squash among them, as the bugs prefer the squash, from which they may be collected. Cleaning up the vines in the fall is evidently of importance in reducing the number which will hibernate The Squash Ladybird * Although almost all of the ladybird beetles are exceedingly beneficial, this species, with its near relative the bean-ladybird FiG.'^296. — The squash ladybird (Epilachna boreah's Fab.): a, larva; b, pupa; c, adult beetle — three times natural size; d, egg — four times natural size; e, surface of egg highly magnified. (After Chittenden, U. S. Dept. Agr.) are the exceptions which prove the rule, being the only injurious forms with which we have to contend. Both the beetles and larvae feed on the foliage of various cucurbs, but prefer that of the squash. It is an Eastern species, not being injurious west of the Mississippi * Epilachna borealis Fab. Family Coccinellidce. See F. H. Chittenden, Bulletin 19, n. s., Div. Ent., U. S. Dept. Agr.; J. B. Smith, Bulletin 94, N. J. Agr. Exp. Sta. 352 INSECT PESTS OF FARM, GARDEN AND ORCHARD and being most troublesome in the Middle Atlantic States. The beetle is nearly hemispherical in shape, slightly oval, about one- third inch long, yellowish or reddish-brown, marked with seven black spots on each wing-cover and four smaller ones on the thorax as shown in Fig. 296. Life History. — The life history, as given by Dr. Chittenden for the District of Columbia and northward, is as follows: " The insect hibernates in the adult condition imder bark or other convenient shelter and appears abroad sometime in May or June. Egg deposition has been observed in the latter part of June, and there is evidence that the eggs are deposited also much later." The eggs are about three- tenths inch long, elongate oval of a yellow color, and laid in irreg- ular clusters of from 12 to 50. " They hatch in from six to nine days, and the larvae begin to feed at once on the leaves, causing them to wither and die." The larva is yellow, with six rows of black branching spines, and is about one-half inch long when grown. "The larva attains full development in from two to four weeks,ceases f eeding,and attaches itself by its anal extremity to a leaf, and next day sheds its larval skin, which is pushed down toward the end of the body, when the pupa stage is assumed. The larva matures anytime from the middle of July to near the middle of September. In the pupa state the insect remains from six to nine days, when the skin separates down the back and the perfect beetle emerges, the new brood appearing as early as the last of July. After feeding for some time the beetles disappear for hiber- nation, . . . beginning about the middle of September." The adults have the habit of marking out a circular area of the leaf, which seems to cause the tissue to wilt, and then feeding within Fig. 297. — Work of the squash lady- bird — greatly reduced. (After W E. Britton.) INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. 353 this area. The larvae are to be found feeding on the under surface of the foHage in July and August. Control. — Usually hand picking the beetles and eggs will control the pest, but if abundant it may be readily destroyed by spraying or dusting with arsenicals. The Squash-vine Borer * In many localities the most serious pest of squash is the Squash-vine Borer, and although other cucurbs are sometimes injured, they are relatively free from attack if squash or pumpkins Fig. 298. — The squash-vine borer {Melittia satyriniformis Hbn.): a, male moth; b, female with wings folded at rest; c, eggs shown on bit of stem; d, full-grown larva in vine; e, pupa; /, pupal cell — all one-third larger than natural size. (After Chittenden, U. S. Dept. Agr.) are present. The larvse bore in the stems, causing them to rot where affected, so that they break off and the plant wilts and dies. The presence of the borer is indicated by the coarse yellowish excrement which it forces from its burrow and which is found on the ground beneath, and by the sudden wilting of the leaves. Injury is most severe at the base of the vine, which gradually decays, so that it is severed and the whole plant dies. A half- dozen or more larvae are often found in a single stem, and as many as forty have been taken from one vine, the larvae attacking all parts of the vine and even the petioles and large ribs of the leaves when abundant. Injury is worst on Hubbard, marrow, cymlings and late varieties of squash. * Melittia satyriniformis Hbn. Family Sesiidce. Farmers' Bulletin 668, U. S. Dept. Agr. 354 INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. The adult is one of the clear-winged moths with a wing expanse of about li inches, the fore- wings being opaque, dark ohve green in color, with a metallic lustre and a fringe of brownish black. The hind-wings are transparent, with a bluish reflection, and the veins and marginal fringe black. The abdomen is marked with orange, or red, black and bronze, and the legs are bright orange, with tarsi black with white bands. The species occurs throughout the states east of the Rockies and southward into Central and South America. Fig. 299. — A squash stem cut open showing borers within. (Photo by Quaintance.) Life History. — The moths appear soon after their food-plants start growth, from mid-April along the Gulf Coast to June 1st, in New Jersey, and late June or early July in Connecticut. They fly only in the daytime, and their clear wings and brightly marked bodies give them a close resemblance to large wasps. The eggs are laid on all parts of the plant, but chiefly on the stems, par- ticularly near the base. The oval egg is of a dull red color and about one-twenty-fifth inch long. The moth deposits her eggs singly, and one individual has been observed to lay as many as 212. They hatch in one or two weeks. The young larva enters the main stem and tunnels through it, and often enters the leaf- INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. 355 petioles branching from it. It is a soft, stout, whitish caterpillar, with a small black head, and about one inch long when full grown. The larvae reach maturity in about four weeks and then enter the earth, where they make tough silken cocoons, coated with particles of earth, an inch or two below the surface. In the South the larvae transform to pupae from which a second generation of moths emerges in late July, but in the North the larvae hibernate in the cocoons over winter, and transform the next spring. The pupa is about five-eighths inch long, dark brown, and with a horn-like process on the head between the eyes. By the aid of this the pupa cuts open one end of the cocoon and with the hook-like spines on the abdomen wriggles to the surface of the earth before transforming to the moth. As indicated, there is but one generation in the North, a partial second brood in the latitude of New Jersey and the District of Columbia, and two full generations in the South. Control. — ^As the larvas work within the vines, insecticide treatment is useless, and the pest must be controlled by methods of culture. Obviously the vines should be raked up and destroyed as soon as the crop is gathered, so as to destroy all of the borers within them. As the larvae or pupae hibernate over winter in the soil, it has been found that frequent light harrowing in the fall will bring them to the surface, and that deep plowing in the early spring will then bury any surviving so that the moths cannot emerge. Rotation of the crop will evidently decrease the number of moths. Where the pest is abundant late squash may be protected by planting rows of early summer squashes as soon as possible. These will attract the moths so that there will be relatively few eggs deposited on the main crop planted later. As soon as the early crop is gathered, or as soon as it becomes well infested, if it is used only for a trap, the vines should be raked up and burned so as to destroy all eggs and larvae. It is well to cover the vines with earth one or two feet from the base so as to induce the growth of secondary roots, which will support the plant in case the vine is severed lower down. The old- fashioned method of shtting the vines with a knife and thus killing the borers is about the only means of destroying them after they have become established. The position of a borer may 356 INSECT PESTS OF FARM, GARDEN AND ORCHARD be detected by the excrement extruded from its burrow, and if the wound be covered with moist earth it will assist the healing. Destroy the parent moths whenever they are seen. Fig. 300. — The pickle worm (Diaphania nitidalis Cramer) : larva, pupa, and adult — all enlarged. (Photos by Quaintance.) The Pickle Worm * The pickle worm is so called because it was first noted as injuring cucumbers grown for pickling, but in the Gulf States, where it is most injurious it is more commonly a pest of melons, * Diaphania nitidalis Cramer. Family PyraustidcE. See A. L. Quaint- ance, Bulletin 54, Ga. Agr. Exp. Sta., R.I. Smith, Bulletin 214, N. C. Agr. Exp. Sta. . INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc 357 and, with the following species, with which it is often confused, is often known as the " melon worm." Injury in the Middle States occurs only periodically, though it has been noted in Illinois and southern Michigan, but in the Gulf States it is always a serious pest of all the cucurbs, destroying the blossoms, mining the stems, and boring into the ripening fruit. The moth has a wing expanse of about Ij inches, is yellowish- brown with a purplish iridescence, and is readily recognized by an irregular yellowish transparent spot on the middle of the fore-wings, and the basal half of the hind-wings of the same color. The abdomen terminates in a conspicuous brush of large blackish scales. Life History. — The moths emerge in late spring and deposit the eggs either singly or in clusters of 3 to 8 on the flowers, buds, or tender terminals. The yellowish-white egg is about one- thirtieth inch long, and rather elliptical. The first larvae are to be found in Georgia by the middle of June. The young larvse which hatch from eggs laid on the terminals bore into stems and leaves and later often tunnel out the vines like the squash-vine borer. Those' from eggs laid on the blossoms usu- ally feed in the blossoms, and a half-dozen may often be found feeding in single squash blossoms, for which they seem to have a decided preference. As they grow older the larvse warder from one plant to another; often boring into several fruits. The older larvae bore into the fruit, the excrement being pushed out from the orifice and later accumulating in the cavity within. A single larva boring into the rind will do sufficient injury to start decay and ruin the fruit, and often a half- dozen or more will be found in a single melon. Until half grown the larvae are marked with transverse rows of black spots. The full-grown larva is about three-quarters inch long, greenish or yellowish-green, with head and prothoracic shield brown. The larva reaches maturity in about two weeks, when a thin silken cocoon is made in the fold of a leaf in which the pupal stage is assumed, which occupies about a week. The pupa is one-haK to one inch long, brown, with wing and leg sheaths lighter, and the tip of the abdomen bears a group of short curved spines which hold the pupa more securely in the cocoon. During 358 INSECT PESTS OF FARM GARDEN AND ORCHARD July and August the complete life cycle requires about four weeks in Georgia, and at least three definite generations have been recognized, the injury by the larvae being most severe in July and August, evidently by the second generation. The winter is passed in the pupal stage in the foliage or trash remaining on the field. Control. — As injury is worst in late summer, early plantings and early-maturing varieties are but little injured. The thorough de- struction of the vines, foliage, and trash on the field after the crop is secured is of the utmost import- ance in controlling this as well as other pests of cu curbs, and may probably be accomplished with this species by deeply plowing under the refuse. Professor A. L. Quaint- ance, to whom we are indebted for our knowledge of this pest, has found that the moths greatly prefer to oviposit on squash and that it may be successfully used as a trap crop for the protection of other cu- curbs. Rows of summer squash should be planted through the cu- cumber or melon fields as early as possible, the rows being planted every two weeks so there will be flowers through July. The squash bloom, with the contained larvae, T. o/M CI 1 ri ■ e L J must be collected and destroyed at Fig. 301. — Squasli flower infested . , ^^ , • i with pickle worms. (Photo by frequent mtervals. otherwise the Quaintance.) squash will merely augment the in- jury, as the larvae will migrate to the crop. Careful tests of this method showed almost complete protection to muskmelons. The use of arsenicals has been of little value against this pest as far as tested, but as they should be applied to control the next species, may be of some incidental value. INSECTS INJURIOUS TO MELONS, CUCUMBERS, Etc. 359 The Melon Caterpillar * This species is very similar to the last in life history and habits and is very commonly confused with it. It seems to be commonly Fig. 302. — Pickle worms at work on a cucumber. (Photo by Quaintance.) injurious only in the Gulf States, though the moths have been taken from Canada to Central America and injury has been seen in Kansas. The moth is a beautiful insect with wings of a pearly iridescent whiteness, bordered with brown- ish-black and expanding about an inch. The anterior half of the thorax and head is the same color as the wing border, while the abdomen is white, tinged with brownish toward the tip, which is surmounted by a brush of long dark scales. The larviE are very similar to those of the pickle worm, and the life history so far as ascertained seems to be prac- tically the same. The essential difference in the habits of this species is that the young larvae very commonly feed on the foliage. Later on they mine into the stems and fruit and are readily confused with those of the last species. Control. — The fact that the young larvae feed on the foliage makes it possible fco destroy them with arsenicals, and by * Diaphania hyalinata Linn. Family Pyraustidce. See A. L. Quaintance, Bulletin 45, Geo. Agr. Exp. Sta., p. 42; R. I. Smith, Bulletin 214, N. C. Agr. Exp. Sta. Fig. 303. — The melon-worm moth {Diaphania hyalinita Linn.) — en- larged. (Photo by Quaintance.) 360 INSECT PESTS OF FARM, GARDEN AND ORCHARD spraying the young foliage with arsenate of lead 3 pounds to the barrel, as advised for the striped cucumber-beetle, they should Fiu. 304. — The melon-worm — enlargad. (Photo by R. I. Smith.) be readily controlled. The cultural methods advised for the con- trol of the last epecies will of course be equally applicable for this. CHAPTER XIX MISCELLANEOUS GARDEN INSECTS The Pale-striped Flea-beetle * Enormous numbers of the Pale-striped Flea-beetles often appear in late June or early July and nearly ruin the young crops they may attack before being brought under control. Such outbreaks occur only periodically, so that usually the grower is Fig. 305. — The pale-striped flea-beetle (Systena blanda Mels.): a, larva; b, beetle; c. eggs; d, sculpture of egg; e, anal segrnent of larva from side; /, same from above; a, d, six times natural size; e, f, more en- laiged; g, the banded flea-beetle {Systena tceniata Say) — six times natural size. (After Chittenden, U. S. Dept. Agr.) unprepared to cope with them, which is true of the appearance of many of our worst insect pests. These flea-beetles are almost omnivorous as regards food, for although particularly injurious to corn and tomatoes, they have also injured beans, beets, pota- toes, egg-plant, carrots, melons and other cucurbs, turnips and other crucifers, strawberry, cotton, oats, peanuts, pear foliage, etc., * Systena bianda Mels. Family Chrysomelidoe. See F. H. Chittenden Bulletin, 23, n. s., Div. Ent., U. "S. Dept. Agr., p. 22; S. A. Forbes, 18th Report State Ent., 111., p. 21. 361 GARDEN PLANT-LICE Fig. 306. — General recommendations and information concerning plant-lice of the garden, as issued by the Bureau of Entomology, U. S. Dept. Agr 362 INSECTS INJURIOUS TO MISCELLANEOUS CROPS 363 and many common weeds, so that it may be safely said that when abundant they will attack almost any crop at hand. The species seems to occur practically throughout the United States, but injury has been most common in the Middle States east of the plains. The beetle is about one-eighth inch long, cream-colored, with the wing-covers marked with three stripes of dull light-brown, and the eyes and abdomen are black. A nearly related species, the banded flea-beetle,* is very similar in appearance, the dark stripes being expanded until it is a poHshed black with two white stripes (Fig. 3056), and the two species have until recently been commonly considered as identical. They are similar in Hfe history and habits so far as known, and may be considered as the same for practical purposes. Life History . . — Very little is known of the hfe history. The beetles usually appear in late June and early July, coming out in enormous numbers, gnawing small holes in the fohage of the plants attacked, so that when abundant they completely defoliate the plant in two or three days and often necessitate replanting. Control. — The destruction of the weeds on which the larvae develop is of obvious importance, and it would be well to plow under deeply any fields grown up in weeds during late summer. Bordeaux mixture is possibly the best repellant for these beetles, though they will be driven off by covering the plants with any dust which thoroughly coats the foliage. Usually the best method will be to spray the plants thoroughly with Bordeaux mixture containing 3 pounds of arsenate of lead or one-third pound Paris green per barrel. All parts of the fohage must be thoroughly coated. Good success has also attended dusting the plants with Paris green and flour and by spraying the beetles with kerosene emulsion. Powdered arsenate of lead dusted over the fohage while the dew is on would probably prove effective, or it might be sprayed at the rate of 3 to 5 pounds to the barrel. The Garden Webworm f The term garden webworm is possibly a misnomer, for although these httle caterpillars frequently do more or less injury to various * Systena tceniata Say. ^ Loxostege similalis Gn. Family Ptjraustidoe. See C. V. Riley, Report U. S. Comm. Agr. for 1885, p. 265; Sanderson, Bulletin 57, Bureau of Ento- mology, U. S. Dept. Agr., p. 11. 364 INSECT PESTS OF FARM, GARDEN AND ORCHARD garden crops when they become overabundant and migrate to them from the weeds on which they normally feed, and occasionally do some damage to sugar beets, they are best known as a pest of corn and cotton. Though the species occurs throughout the United States and south to South America, it has been most injurious from Nebraska southward and east to Mississippi and Illinois. The larvae feed normally on the pigweed or careless weed {Amaranthus spp.) from which they sometimes receive the local name of "careless worm," and only when they become overabundant on these weeds do they usually increase sufficiently to migrate from them and attack crops. The moth is a yellowish, buff or grayish-brown color, marked as shown in Fig. 307, and with a wing expanse of about three- quarters of an inch. The larva also varies in color from pale and greenish-yellow to dark yellow, and is marked with numerous black tubercles as shown in Fig. 307, b, c. Life History. — The hibernating habits are not known, but from analogy with the beet webworm, and the appearance of the moths, it seems probable that the winter is passed by the larvae or pupae in the soil. The moths appear in Texas by mid-April and in central Illi- nois in late May Fig. 307. — The garden webworm (Loxostege simi- and early June. Mis Gn.):a, male moth; b, c larva?; d anal rpi p „pii^^is!h pp-o-s segment of same; e, abdominal segment of same ^'^^ yellowisn eggs from side; /, pupa; g, tip of abdomen of same; are laid on the foli- a, b, c, f, somewhat enlarged; d, e, g, more en- . ,, + u^„ larged. (After Riley and Chittenden, U. S. Dept. age m small patches Agr.) of from 8 to 20 and in Texas hatch in three or four days. The larvae of the first generations feed on weeds or alfalfa, where it is grown, and then migrate to corn and cotton or garden truck, the former crops being attacked when six or eight inches high. In feeding the caterpillars spin a fine web, which gradually envelopes the plant, of which nothing is left but the skeletons of the leaves when the INSECTS INJURIOUS TO MISCELLANEOUS CROPS 365 larvae are abundant. The larvae become full grown in about three weeks in summer, when they descend to the soil and pupate in small silken cells on or just below the surface. The moths emerge about eight days later, so that in midsummer the com- plete hfe cycle -occupies about a month. In Texas there are probably five generations a year, and in Nebraska and IlUnois three or four generations. Control. — The plowing of infested land in late fall or winter, or thorough disking of alfalfa will be found largety to control the pest. Where it appears on cultivated crops it may be readily destroyed by at once spraying or dusting with arsenate of lead. The destruction of the weeds upon which it feeds is obviously important in preventing the undue multiphcation of the pest. The Rhubarb Curculio * Rhubarb is but little troubled with insect pests, but occa- sionally the stalks are found with numerous punctures from Fig. 308. — -The rhubarb curculio (Lixus concavus Say): a, beetle; h, egg; c, newly hatched larva; d, full grown larva; e, pupa; /, back view of last abdominal segment of pupa — all about twice natural size. (After Chit- tenden, U. S. Dept. Agr.) which the juice exudes. This has been caused by the feeding and oviposition of a large rusty-brown snout-beetle, which is usually found on the affected plants. It is about three-quarters * Lixus concavus Say. Family Curculionidoe. See F. H. Chittenden, Bulletin 23, n. s., Division of Entomology, p. 61. 366 INSECT PESTS OF FARM, GARDEN AND ORCHARD inch long, and will be readily recognized from Fig. 308 The beetles hibernate over winter and feed on dock, in the stalks of which the eggs are laid in May. Although eggs are laid in rhu- barb, they fail to hatch or the young larvse die. The grubs become full grown by midsummer and the beetles emerge in late summer and feed a little before entering hibernation. Control. — As the beetles are sluggish and readily found, they may be easily destroyed by handpicking. Dock plants near the rhubarb patch should be pulled and destroyed in early summer after the beetles have finished laying their eggs, The Celery Caterpillar * Everyone who grows celery, parsley or carrots is famihar with the large, black-striped, green caterpillar which feeds on Fig. 309. — The celery caterpillar (Papilio polyxenes Fab.) : a, full grown larva, side view; b, front view of head showing extended osmateria; c, male butterfly; d, egg; e, young larva; /, suspended chrysalis — about natural size except d. (After Chittenden, U. S. Dept. Agr.) their foliage, as it is probably the most common pest of those plants in all parts of the country, ragging the foliage and attack- ing the blossoms and undeveloped seeds. It is the larva of our most common black swallowtail butterfly, shown natural size in Fig. 309. The wings of the male are velvety black with bands * Papilio polyxenes Fab. Family Papilionidoe. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 367 of yellow spots. On the inner angle of the hind-wing is a well- marked eyespot, and the hind-wing terminates in a distinct "tail." The female is somewhat larger, the inner row of yellow spots is wanting, and the hind-wings are covered with pale-blue scales on the posterior half. There is considerable variation, however, in the color of both sexes. Life History. — In the North the winter is passed in the chrys- alis stage and the butterflies appear in May in New England, while in the far South the butterflies hibernate over winter and appear in March or April. The eggs are laid on the fohage and are of a globular form, about one-twenty-fifth inch in diameter, at first pale honey-yellow, but later reddish-brown. The eggs hatch in from four to nine days. The young larvae are quite dissimilar from the older stages, being nearly black with a white band around the middle of the body (Fig. 309e). The larvae feed exclusively on umbelliferous plants, including besides those mentioned, caraway, fennel, parsnip, dill, wild carrot, wild pars- nip, and other weeds of this family. The full-grown larva is shown, natural size, in Fig. 309, a. It is bright green, sometimes yellowish, and marked with rings and spots of velvety black as illustrated. Just back of the pro thorax is a pair of membranous yellow horns called osmateria, which give off a pecuHar pungent odor, which is quite disagreeable and evidently aids in frighten- ing away enemies. These osmateria are soft, retractile organs, which are drawn back between the segments and are extruded only when the larva is disturbed. In the far South the larva will become grown in ten days, but in the North it requires three to four weeks. The cater- pillar then attaches itself to some part of the plant by the anal prolegs, and fastens a strong loop of silk around the thorax, and sheds its skin, leaving the chrysahs or pupa firmly attached ;to the leaf or stem as shown in Fig. 309, /. The chrysahs is a dull gray color marked with black and brown and about 114 inches long. In from ten days to two weeks the butterfly emerges from the chrysahs. Thus the complete life cycle may be passed in twenty-two days in the South to eight weeks in the North. In the North there are but two generations a year, while in the South there are probably three or four. Control. — The caterpillars are so readily seen, and if not seen they soon reveal their presence by the peculiar odor when dis- 368 INSECT PESTS OF FARM, GARDEN AND ORCHARD turbed, that they may usually be picked off and crushed, and so rarely become sufficiently numerous to warrant other treatment. They may be readily controlled by spraying or dusting with arsenicals. The Celery Looper * This species is very closely related to the cabbage looper and occurs throughout the Northern States east of the Rocky Mountains. According to Forbes and Hart it is more common than the cabbage looper in Illinois, where it is a serious pest of celery and has been reared on sugar-beet, but elsewhere it is not as common. The moth has a wing expanse of about two inches, the fore- wings being purplish brown with darker shades of velvety brown Fig. 310. — The celery looper (Antogragha simplex Guen.): male moth and larva — somewhat enlarged. (After Chittenden, U. S. Dept. Agr ) and with a prominent silvery white discal spot, while the hind- wings are yellowish, strongly banded with dark fuscous. The caterpillar or larva is similar to that of the cabbage looper, but the spiracles are surrounded with black rings, while in the cabbage looper these rings are indistinct or wanting. Forbes and Hart believe that there are three broods in a year. "The caterpillars of the first generation of the year hatch late in May and get their growth late in June or early in July. The life of the second generation extends from the first part of July to the middle of September, and the third begins to issue from the egg early in October. This brood hibernates about half grown, attaining full size during the latter part of April." Control. — No accounts of experiments in control are on record, but doubtless the same measures as used against the cabbage looper will be found applicable. * Antographa simplex Guen. Family Noctuidoe. See Chittenden, Bulle- tin 33, Division of Entomology, U. S. Dept. Agr., p. 73. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 369 The Carrot-beetle * The Carrot-beetle is a native species which has been particu- larly injurious to carrots along the Atlantic Coast from Long Island through the Gulf States. The species occurs, however, very generally throughout the country as far north as central Indiana, and on the Pacific coast. It has a considerable number of food-plants; in Louisiana and Mississippi it has injured the corn crop, the beetles cutting the corn just above the roots; in Illinois the beetles injured sunflowers and sweet potatoes; in Indiana they attacked carrots, celery and and parsnips; in Texas they have injured potatoes and shrubs and vegetables of various kinds; and in Nebraska they have damaged sugar-beets. The damage is done entirely by the adult beetles, which arc among the smaller of the May- beetles or June-bugs, measure one-half to five-eighths of an inch long, and are from reddish- brown to nearly black in color. The beetles gouge into the roots or stems just below the surface of the soil, often ruining the root for market without injuring the top. The injury may occur by hibernated beetles in the spring from April to June or by newly transformed individuals in late summer or autumn. The Ufe history has not been studied, but is probably very similar to that of Lachnosterna. Control. — No very satisfactory means of control have been tried in a practical way. It is stated that lime scattered over infested fields has driven the beetles away. It is evident that after the crop is gathered infested fields should be pastured with hogs, if possible, or plowed deeply, and plowed again in the spring. Evidently further study of the habits of the pest is necessary before satisfactory means of control may be devised. * Ligyrus gibbosus DeG. Family Scaraboeidoe. See F. H. Chittenden, Bulletin 33, n. s., Div. Ent., U. S. Dept. Agr., p. 32, and W. P. Hayes, Journal Ec. Ent. Vol. 10, pp. 253-261, 1919. Fig. 311. — The carrot-ljectlc [Liijiirus gibbosus DeG.) — much enlarged. (After Forbes.) 370 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Carrot Rust-fly * The Carrot Rust-fly is a European species, being a serious •pest of carrots in England and Germany, which has been known in Canada since 1885 and appeared in New York in 1901 and since then in New Hampshire. The larva or maggot which does the injury very much resembles the cheese maggot or skipper in general appearance, is a rather dark brown, and a little less than one-third inch long. The parent fly is about one-sixth inch long with a wing expanse of three-tenths inch, and is a dark Fig. 312.— -The carrot rust-fly (Psila rosae Fab.): "b, male fly; o, female flys, side view; a, antenna of male; h, full-grown larva from side; c, spiracle of same; a, anal extremity from the end; e, puparium; /, young larva; g, anal segment from the side — eight times natural size except a, c, d, g, more enlarged. (After Chittenden, U. S. Dept. Agr.) blackish-green color, sparsely clothed with yellow hairs, and with pale yellow head and legs, except the eyes, which are black. "Attack on carrots is not difficult of recognition. The leaves of the young plants early in the spring turn reddish, and the roots are found to be blotched with rusty patches, particularly toward their tips. The roots when stored for winter, although not always manifesting any degree of injury on the outer surface, may at times be perforated in all directions by dirty brownish burrows, from which the whitish or yellowish larvae may be found sometimes projecting." Celery is also attacked, the larvae * Psila rosoe Fab. Family Psilidoe. See Chittenden, Bulletin 33, n. s. Division of Entomology, U. S. Dept. Agr., p. 26. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 371 eating the thick part of the root when it is half grown, stunting the plant so as to make it worthless for market. The life history of the species does not seem to have been carefully observed, but from analogy is probably somewhat similar to that of the cabbage root-maggot, except that the maggots of the carrot rust-fly develop and transform on carrots in storage if the tem- perature be sufficient. Control. — Control measures as recommended for this insect have not proven of any great benefit so we must wait for addi- tional information before making definite suggestions. The Parsnip Webworm * The Parsnip Webworm is quite a common pest of the forming Fig. 313. — ^The parsnip webworm (Depressaria heracliana De G.): a, moth, b, c, larvae; d, pupa; e, anal extremity of pupa;/, umbel of parsnip webbed together by the larvse — natural size. (After Riley.) seed of the parsnip, but fortunately it seems to prefer wild carrot as a breeding plant. It is an imported species, occurring in north- ern Europe, which was first observed in this country in 1873 and since then has become generally distributed over the Northern States and Canada westward to the Mississippi, The moth is a grayish-buff or pale ochreous color, marked with fuscous, the wings expanding about three-quarters of an inch. The larva is a pale yellowish, greenish or bluish-gray, with con- spicuous black tubercles, the head and prothoracic shield black, * Depressaria heracliana DeG. Family (Ecophoridm. See C. V. Riley "Insect Life," Vol. I, p. 94. " 372 INSECT PESTS OF FARM, GARDEN AND ORCHARD and is about half an inch long when grown. The larvae web the flower-heads together until they are contracted into masses of web and excrement ( as shown in the illustration. "After the larvae have consumed the flowers and unripe seeds and become nearly full grown, they enter the hollow stems of the plant by burrowing their way inside, generally at the axils of the leaves, and then feed upon the soft, white lining of the interior. Here, inside the hollow stem, they change to the pupa state. The larvae are moderately gregarious. They will sometimes eat newly sown parsnips after the older plants originally attacked have been destroyed, in such cases eating the tender green leaves, while of the older plants they eat only the flower-heads and interior lining of the stems." The moths appear in late July and early August. Control. — Thorough spraying or dusting with arsenicals will destroy the caterpillars, according to Chittenden. If the flowers are destroyed before they are noticed, cut off and burn all infested stems before the moths emerge from the pupae. Obviously it will be important to avoid planting parsnips in or near waste places which have grown up in wild carrot. The Onion Thrips * The small yellowish "thrips" which chafe the epidermis from the green leaves, causing them to dry out, whiten and die, have become well known to onion growers in practically all parts of the United States where onions are raised extensively. It is a European insect, occurring in Germany and Russia, and has also been imported into the Bermudas. The adult thrips is about one-twenty-fifth of an inch long, of a pale yellow color, tinged with blackish. The general appear- ance, much enlarged, is shown in Fig. 314. The slender, elongate body bears two pairs of narrow, bristle-like wings which are of no value for flight. The fore-wing contains two-wing-veins, and the hind-wing but one, the posterior margin of both bearing a * Thrips tabaci Lind. Order Tlujsanoptera. See Quaintance, A. L., Bulletin 46, Fla. Agr. Exp. Sta., "The Strawberry Thrips and the Onion Thrips." Full account and Bibliography; Pergande, Th., "Insect Life," Vol. VII, pp. 292-295; Osborne-Mally, Bulletin 27, Iowa Agr. Exp. Sta., pp. 137-142; Sirrine, Bulletin 83, N. Y. Agr. Exp. Sta., pp. 680-683, Farmers' Bulletin 1007, U. S. D. A. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 373 fringe of long hairs. When at rest the wings he together along the back. The thrips belong to a quite distinct order of insects, the Thysanoptera (or Physopoda), species of which are commonly found in the flowers of the rose and clover. The mouth-parts are quite different from those of any other order of insects, being intermediate between those of biting and sucking insects, the mandibles being reduced to bristle-like structures. Their man- ner of feeding does not seem to be clearly understood, though Fig. 314. — The onion thrips (Thrips iabaci Lind.) — very greatly enlarged. (Photo by Quaintance.) Professor Quaintance states that the onion thrips frequently rasps off and swallows pieces of leaf tissue. However, they are able to destroy the surface tissue of the leaf so that it wilts, and fields badly affected become blighted and white. . This species has quite a list of food-plants, cabbage and cauH- flower often being considerably injured. Among others may be mentioned turnip, kale, sweet clover, squash, cucumber, melon, parsley, tomato, and several common garden flowers and weeds. Life History. — The eggs are slightly less than .01 of an inch long — too small to be visible to the unaided eye — elongate, and curved somewhat kidney-shaped. They are laid singly just beneath the surface of the leaf and hatch in about four days. 374 INSECT PESTS OF FARM, GARDEN AND ORCHARD The young nymphs resemble the adults in shape, but are at first almost transparent in color and then a greenish-yellow. They are frequently found feeding in small groups. Both the young and adults have a pair of sharp spines at the tip of the abdomen which they use to drive away enemies by striking them quickly right and left. Two or three days after birth the skin is shed and another molt occurs five or six days later. With the third stage the wing-pads appear. This stage lasts four days, and during it the insects take no food and remain almost quiet, moving with difficulty. On onions the nymphs have been found mostly on the bulbs in the loose soil. With the next molt, the insect becomes mature and winged. Thus, the total fife cycle as observed by Professor Quaintance in Florida is about sixteen days. In Russia Dr. Lindeman found that a generation required forty-seven days. "In Florida there are probably no distinct broods, as all stages may be found at the same time. Allowing for the fife cycle at sixteen days, a large number of broods could occur during the year, but unfavorable conditions keep them reduced, except daring the spring and perhaps early summer (the worst injury occurring in May and June), so that it will prob- ably not happen that they will develop throughout a year accord- ing to their capabifities." Control. — The best methods of control, according to Dr. Chittenden, include clean farming and crop rotation as pre- ventive measures and spraying with nicotine sulphate as a direct method of kilfing the thrips. High pressure should be used in spraying and the spray should be directed downward so that it will be forced into the crevices between the leaves or stems, in which the thrips conceal themselves. The Imported Onion-maggot * The common white maggot which bores into the roots and bulbs, causing them to wilt and decay, is probably the most important insect pest of the onion. The present species is by far the most commonly injurious and is termed " imported" because it was early known as a pest in Europe and was imported into this country probably in colonial times. * Pegomyia ceparum Bouche. Family Anthomyiidoe. See same references as for cabbage-maggot. Fig. 315. — ^The imported onion-maggot (Pegomyia ceparum Bouch6) : a, adult; b, maggot; c, puparium; d, anal segment of maggot showing spiracles; e, head with mouth-parts — all very much enlarged; / and g show injury to young onions. (After J. B. Smith.) 376 INSECT PESTS OF FARM, GARDEN AND ORCHARD These maggots are the offspring of small flies, somewhat resembling small houseflies and very similar to those of the cabbage root-maggot.* The wings expand about three-eighths of an inch and the body is half that long. The male is gray with black bristles and hairs, the face is white with black hairs, there are three black lines between the wings, and the abdomen bears a row of black spots along the middle. The female is a little larger, incHned to dark yellowish, and with a yellowish face. Life History. — The flies appear in the spring by the time young onions are up and the eggs are deposited in the sheath and in the axils of the leaves, from two to six being placed upon a plant. The eggs are just perceptible to the eye, white, oval, and about one-twenty-fifth of an inch long. The young maggot works its way down from the sheath to the root, upon which it feeds until it is consumed, only the outer skin remaining, and often cuts off the plant completely. Another plant is then attacked and often several young plants are consumed before the maggot is fuU grown. Later in the season the maggots bore into the bulbs, a number of maggots usually being found in a single bulb and their presence being indicated by a slimy mass of soil at the entrace of the cavity. If such bulbs are not killed outright, they usually rot in storage. The first presence of the pest is indicated by the wilting of the young plants, and by the central leaves of the older plants yellowing and dying. The maggots become full grown about two weeks after hatch- ing and are then about three-eighths of an inch long. They are dull white, with the jaws appearing beneath the skin as a short black stripe at the pointed end of the body. The posterior end of the body is obtuse and is cut off obliquely, the margin of the last segment bearing a number of tubercles by which this species may be distinguished from the cabbage-root maggot. (See Slingerland, I.e.) The outer skin of the maggot now becomes hardened and within it the insect transforms to the pupa, which remains in the soil at the base of the plant for about two weeks, when the adult fly emerges. Two or three generations probably occur in the Northern States. Professor R. H. Pettit states that some of the * See Slingerland, Bulletin 78, Cornell Agr. Exp. Sta., p. 495, for characters distinguishing these two species. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 377 flies hibernate while many of the pupae remain in the soil over winter and the flies issue from them in the spring. This com- phcates remedial measures. Control. — Liberal appUcations of commercial fertihzers such as nitrate of soda, which will assist to rapid growth, are of great value in overcoming injury by all root-feeding pests. Thorough culture is of value. Rotation of the onion plot to a point far distant from that of the previous year, the cleaning up of old beds, and plowing them deeply in the fall, will aid in the control. Pull up and destroy the young plants affected as soon as noticed, being careful to dig up the maggots with the roots. The appli- Hm Fig. 316. — The barjed-winged onion-maggot {Chcetopsis cenea Wied.) : a, larva, with spiracular opening highly magnified at left; h, puparium; c, adult fly — all enlarged. (After Riley and Howard, U. S. Dept. Agr.) cation of carbolic emulsion as for the cabbage-root maggot has been advocated and will doubtless lessen the injury by repeUing the adult flies. A more recent method of control is based on the fact that the flies are on the wing and feeding for several days before they lay their eggs and that they may be attracted to sweet sub- stances. A poisoned syrup, sprinkled about the field and on weeds nearby, will attract the flies and kill large numbers before they lay their eggs. The syrup is poisoned as follows: One pint of syrup is mixed with a gallon of water and to this is added one-fifth ounce of sodium arsenite dissolved in a small quantity of hot water. This is sprinkled where it will do the most good at intervals of about a week.* * See Severin and Severin, Journal Econ. Ent., Vol. 8, pp. 342-350, 1915, and Howard, ibid. Vol. II, pp. 82-85, 1918. 378 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Barred-winged Onion-maggot * The adult flies of this species may frequently be found upon corn and are readily recognized by the banded wings. They are similar in size to the last species, but the back is metallic blue- green except the head, which is mostly hoary, with brownish- black eyes. The maggots have been recorded as injurious to corn and sugarcane and have been recently noted in Michigan associated with the common onion-maggot, destroying onions, f The maggots are similar to the onion-maggot but the posterior end is more rounded and may be distinguished from the illus- trations. The winter is passed in the puparium as far as observed. Remedies. — In addition to the measures advocated for the last species, the destruction of the affected onions and the thorough plowing of affected land in the fall is of prime importance. Stored onions which prove infested may be fumigated with carbon bisul- fide to destroy the maggots and puparia and prevent the emerg- ence of the adults. The Asparagus-beetle | This is a well-known pest of asparagus in Europe and was first observed in Queens County, New York, in 1862, where it threatened to destroy the asparagus, one of the most valued crops of the Long Island truckers. Since then it has gradually spread northward to southern New Hampshire, south to North Carolina, and west to Illinois and Wisconsin, and has been found at two points in California. There seems no reason why it should not spread to wherever asparagus is grown, at least in the North- ern States. The beetle is a handsome little creature about one-quarter inch long, blue-black in color, with red thorax, and dark blue wing-covers, marked with lemon-yellow and with reddish bor- ders. The markings of the wing-covers are quite variable, the light color sometimes forming submarginal spots, while in other specimens it becomes so diffused as to form the principal color of the wing-covers. * Chcetopsis aenea Wied. Family Anthomyidce. t See Pettit, Bulletin 200, Mich. Agr. Exp. Sta., p. 206. X Crioceris asparagi Linn. Family ChrysomelidcB. See F. H. Chittenden, Yearbook, U. S. Dept. Agr., 1896, p. 341; Bulletin 66, Bureau of Ent., pp. 6, 93, and Farmers' Bulletin 837. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 379 Both adults and larvse feed upon the tender asparagus shoots in the spring and later attack the fruiting plants. Their attacks render the shoots unfit for market and in many cases their injury has been so severe as to make it extremely difficult to estabhsh new beds. Life History. — The beetles hibernate over winter under what- ever rubbish or shelter may be available near the asparagus patch. About the season that cutting asparagus for market commences they appear and lay the eggs for the first new brood Fig. 317. — The asparagus-beetle (Crioceris asparagi Linn.): eggs, larva, and beetle — all much enlarged. (Photos by W. E. Britton.) The egg is dark brown, oval, nearly one-sixteenth of an inch long and is laid on end. The eggs are deposited upon the stems or foliage, usually two to seven or more in a row. They hatch in from three to eight days. The young larvae at once com- mence to attack the tender shoots, and later in the season feed upon the foliage. They become full grown in from ten days to two weeks. The full grown larva, as shown in the illustra- tion, is about one-third of an inch long, soft and fleshy, much wrinkled, and of a dark gray or olive color, with black head and legs. The mature larva drops to the ground and just be- neath the surface forms a little rounded earth-covered cocoon within which it changes to the pupa, from which the beetle 380 INSECT PESTS OF FARM, GARDEN AND ORCHARD emerges in about a week. Thus the complete life cycle may be passed in a minimum of three weeks at Washington, D. C, where there are possibly four generations in a year, while farther north, six or seven weeks may be required for the life cycle, and there are probably only two generations. 1 The asparagus-beetles are held in check by several natural agencies. Several species of ladybird-beetles feed upon the eggs, while numerous soldier-bugs attack the larvae which they impale on their stout beaks. The adult beetles are often killed by low temperature in the winter, which doubtless limits their northern spread, while the eggs and larvae are sometimes killed by the intense heat of summer, which will also probably hmit the south- ern spread of the species. Control. — One of the best means of control is to keep all shoots cut down in the spring so as to force the beetles to lay their eggs on the young shoots, which are cut for market every few days before the eggs have hatched, and hence no larvae are allowed to hatch. Another method which has proven effective is to cut down all the seed stems but a few rows here and there, so that the beetles will concentrate upon them, and then poison these thor- oughly with arsenicals, or they may be cut down and burned and other rows allowed to grow as traps. Air-slaked lime dusted on the plants in the morning while the dew is on will destroy the soft-bodied larvae very effectively. Another way to destroy the larvae in hot weather is simply to brush them from the plants so that they will drop on the hot soil. As they crawl but slowly few will regain the plants, par- ticularly if the brushing be followed with a cultivator. Probably the most effective means of controlling this pest, which was formerly a very difficult one to combat, is spraying with arsenate of lead. Use 3 pounds to 50 gallons, to which 3 pounds of resin soap should be added to render it more adhesive, although good results have been secured without the sticker. Such spraying should be given as soon as cutting is over and should be repeated once or twice at intervals of ten days. Where the young shoots are kept closely cut and the bed is then sprayed, there should be no trouble to control the pest, and young beds should be kept thoroughly sprayed with arsenate of lead from the time the beetles appear until danger from injury is over. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 381 The Twelve-spotted Asparagus-beetle * The Twelve-spotted Asparagus Beetle is also of European origin, having been first introduced into this country near Balti- more, Md., in 1881. Since then it has become almost as widely distributed as the previous species. The beetles may be distinguished from the last species by the broader wing-covers, each of which is orange-red, marked with six black spots. The chief injury by this species is by the beetles which emerge from hibernation feeding on the young shoots. Later generations attack the foliage, but the larvse seem to prefer to feed upon the ripening berries. The larva is of the same general appearance as that of the preceding spe- cies, but may be dis- tinguished by its orange color. The eggs are laid singly, and are attached on the sides instead of on end. They are deposited mostly on ^ j^ ^^ — , old plants toward Fig. 318.— The twelve-spotted asparagus-beetle (Cri- the ends of the oceris 12-punctata Linn.): a, beetle; b, larva; c, u + U" u u second abdominal segment of larva; d, same of shoots which bear c, asparagi — a, b, enlarged; c, d, more enlarged, ripening berries (After Chittenden, U. S. Dept. Agr.) lower down. Soon after a larva hatches it finds its way to a berry and feeds upon its ripening pulp, from which it migrates to an- other, feeding upon several, perhaps, before full growth is obtained, when it drops to the ground and pupates like the last species. The hfe cycle is essentially the same and there are probably the same number of generations. Control. — The remedies advocated for the previous species will be found satisfactory except those which are directed against the larvse, as the habit of the larva of concealing itself in the berry would make the application of insecticides to the seed- stalks of little use. * Crioceris 12-punctata Linn. See F. H. Chittend3n, I.e., and D. E. Fink, Cornell Univ. Expt. Sta., Bulletin 331. 382 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Asparagus Miner * Occasionally injury by the small white maggots of a fly have been observed in the asparagus beds of Long Island, California, Pennsylvania, Massachusetts and District of Columbia, but the damage seems rarely to be very serious. The adult is a small black fly about one-sixth of an inch long and is usually found on the flowers of the asparagus, and occurs from New England to Tennessee. These flies emerge early in June. The exact manner of egg-laying has not been observed, but the young maggots are Fig. 319. — The asparagus miner (Agromyza simplex Loew) : at left, side view of fly; a, larva; b, thoracic spiracles; c, anal spiracles; d, puparium from side; e, same from above; /, section of asparagus stalk showing injury and location of puparia on detached section — a, e, much enlarged; /, slightly reduced. (After Chittenden, U. S. Dept. Agr.) found mining just beneath the surface of the stalks, especially young stalks. The maggots are about one-fifth of an inch long, pure white, except the black rasping hooks which project from the head. When full grown the maggots change to puparia beneath the epidermis. The next brood of adult flies emerge early in August. A second brood of maggots seems to occur and the puparia of the second brood pass the winter, and from them come the flies early the next summer. Injury from the mining of the maggots has been most serious on seedling and newly set beds, though it may occur on cutting * Agromyza simplex Loew. Family Agromyzidee. See Sirrine, Bulletin 189, N. Y. Agr. Exp. Sta.; Chittenden, Bulletin 66, Part I, Bureau of Ento- mology, pp. 1 and 5, Fig. 2, and D. E. Fink, Bulletin 331. Cornell Univ. Agr. Exp. Station. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 383 beds, being apparent by the plants turning yellow and dying much ear her than they naturally do. Pulling the old stalks and burning them in late summer seems to be the best means for controlling the pest, from our present knowledge of it, which, however, is still rather meager. Dr. Chittenden has suggested that letting a few stalks grow as a trap-crop to which the flies might be lured, and then destroying these stalks, might protect the cutting beds. D. E. Fink (I.e.) recommends the addition of syrup to the arsenical apphed for the beetles so that it will act as a poisoned bait for the flies. In addition to this he suggests pulling the in- fested stalks in late fall and early spring and i ml^^m'a I destroying them. The Sweet-potato Flea-beetle * As soon as the sweet-potato plants are set out they are often attacked by hordes of hungry little brownish flea-beetles. Small channels are eaten out of both surfaces of the leaf in a very characteristic manner, quite different from the work of other flea- beetles (Fig. 320), and often the whole sur- face is seared but never punctured. As a result many of the leaves of the seedling are killed outright, turn brown, and decay, while new leaves put out from below, thus check- ing the growth. These attacks have been found to be worst on low land and that pre- viously in sweet potatoes, and are always first noticed near fence rows or woodland where the beetles have hibernated. The beetle is bronzed or brassy-brown about one-sixteenth inch long, thick set, and the wing-covers when seen under a lens are deeply striated. Fig. 320.— The sweet- potato flea-beetle {Chcetocnema confinis Lee.) : adult and larva — much enlarged. (After J. B. Smith.) * Chcetocnema confinis Leo. Family Chryso7nelidoe. See Sanderson, Bul- letin 59, Md. Agr. Exp. Sta.; J. B. Smith, Bulletin 229, N. J. Agr. Exp. Sta. 384 INSECT PESTS OF FARM, GARDEN AND ORCHARD Life History. — The beetles hibernate over winter in rubbish, under logs, leaves or other vegetation^ and emerge early in May. They mate as soon as they have fed a httle, and disappear by the middle of June in New Jersey. But little is known of the early stages of the insect and they have never been found on sweet-potato plants. The larvae have been found, however, feeding on the roots of bindweed. The larva (Fig. 320) is a slender, white grub, about one-eighth inch long, and feeds exter- nally upon the smaller roots. The beetles appear again in August, but do not as a rule feed on sweet potatoes, preferring bindweeds and wild morning-glories, from which they disappear in late September, Control. — By dipping the plants in arsenate of lead, 1 pound to 10 gallons of water, as they are being set, they will be pro- tected and any beetles feeding on them will be killed. The plants should be allowed to dry slightly before being set. Dip- ping the plants is much better than spraying them later, as it is practically impossible to completely cover the plant by spray- ing, as may be done in dipping, which is much quicker and less expensive. Late-planted sweet potatoes are much less seriously injured, as the beetles will seek out their wild food-plants and become established upon them, so that late planting may be resorted to when necessary or more convenient. Well grown, stocky plants will better withstand injury, and liberal fertiliza- tion will enable them to make a quick growth even if slightly checked. Tortoise-beetles or Gold-bugs * Of all the insects affecting the sweet potato, the brilhant little golden beetles which form one tribe {Cassidce) of the large family of leaf -beetles, are the most common and are quite pecuhar to it. They are beautiful insects, some of the species appearing like drops of molten gold, which has given them the name of "gold-bugs," while the broad expansion of the thorax and wing- covers gives them a fancied resemblance to a tortoise; hence the name "tortoise-beetles." The species affecting the sweet potato are classed in three different genera, but are sufficiently alike in their general habits and Kfe history to be treated together. * Family Chrysomelidce. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 385 Life History. — The beetles hibernate over winter and in the spring before the sweet-potato plants are set they feed on their native food-plant, the morning glory. As soon as the plants are set out, the beetles commence to eat large round holes in the leaves, and so riddle them that many often must be replanted. The worst damage, however, is done to the set on which the eggs are laid. Rarely are the new shoots seriously eaten or are eggs laid upon them. The larvae hatch during the first half of June in Maryland, and require slightly over two weeks to become Fig. 32L — Above — The golden tortoise-beetle [Coptocycla bicolor Fab.): a, h, larvae; c, pupa; d, beetle; egg at right — all enlarged. (After Riley.) — Below The two-striped sweet-potato beetle (Cassida bimttataSay): 1, larvae on leaf; 2, larva; 3, pupa; 4, beetle — all enlarged. (After Riley.) full grown. Though the larvae do considerable damage by eating the foliage, it is not nearly as serious as that done by the beetles. The larvae are almost as disagreeable as the adult beetles are attractive, but are nevertheless very interesting creatures. Each of them is provided with a tail-like fork at the end of the body which is almost as long as the body, and in those species in which it is depressed, entirely conceals the insect. Upon this fork is heaped the excrement and cast skins of the larva, and when covered by this "umbrella" it is with great difficulty that the larva is distinguished from a bit of mud or a bird-dropping. The manner in which this fork increases with the size of the 386 INSECT PESTS OF FARM, GARDEN AND ORCHARD larva is rather interesting. At each molt, the faeci-fork of the last stage is held upon the new fseci-fork, and in this way those of the different stages are telescoped, the one inside the other, and the stage of growth of the larva may be readily determined by the number of cast skins held on the fork. From the like- ness of this burden to a pack, the larvae are often known as "peddlers." In order more firmly to bind the excrement and cast skins to the fork, the larvae fasten them together by a fine network of silken threads, which are attached to the spines at the sides of the body. When fully grown the larva fastens itself to a leaf, its skin splits open along the back, and from it comes the pupa, which is held to the leaf by its caudal fork, which is securely encased in the fseci-fork of the larval skin. About a week later the adult beetle emerges, eats for a few days and then disappears from the sweet-potato patch until the following spring, doubtless feeding on morning glory until it enters hibernation. Control. — From the similarity of their life history and habits all of these species may be treated at once. As the beetles do the most injury just after the plants are set, they should be dipped in arsenate of lead when setting, as advised for the flea-beetle. If this has not been done or if the beetles are injurious in the forcing bed, the plants should be thoroughly sprayed with arse- nate of lead, 3 pounds .per barrel or Paris green, | pound per barrel with | pound of freshly slaked hme. The Sweet-potato Root-borer * Since 1890 sweet potatoes have been seriously injured in parts of Texas and Louisiana by a small white grub which bores into the stems and tubers both in the field and in storage, but strangely it has not spread elsewhere in this country. In Texas the worst injury has been in Calhoun and neighboring counties along the Gulf Coast where extensive growing of sweet potatoes has been abandoned on account of the pest. During recent years it has spread to central Texas and there seems to be no reason why it should not spread over the Gulf States. It is a cosmopolitan insect being reported from China, India, Madagascar, AustraHa and Cuba. It was first noticed in the vicinity of New Orleans * Cylas formicarius Oliv. Family Curculionidce. See Farmers' Bulletin 1020, U. S. Dept. Agr. INSECTS INJURIOUS TO MISCELLANEOUS CROPS 387 in 1875 and has since spread northward along the Mississippi.* In 1879 it was reported from Florida and was studied by Pro- fessor J. H. Comstock.f The adult beetle is a rather slender insect, about one-quarter inch long, of a bluish-black color, with a reddish-brown pro- thorax, and has received its specific name, formicarius, from its fancied resemblance to an ant. Life History.— The yellowish-white, oval eggs are deposited in small cavities eaten out by the mother beetle either at the base of the vine or at the stem end of the tuberous root, or in the Fig. 322. — Present known distribution of the sweet-potato weevil in the southern United States. (Farmers' Bulletin 1020). tubers in storage. The small grubs commence to burrow in the vine, sometimes maturing in the vine before any tubers have developed, but usually they descend to the tubers, which in the course of the season, and with the aid of the beetles, they thor- oughly riddle. The full-grown larva is about one-quarter inch long, whitish with light brown head, the segments are strongly constricted, and the legs are wanting, being represented by mere tubercles. The grub forms a small cavity at the end of the burrow and transforms to the pupa. In this stage it remains from one to two weeks, when the adult beetle emerges and after a few days commences to lay eggs for another generation. The whole Hfe cycle requires from thirty to forty days, so that there may be several generations in a year. Professor Comstock having * Bulletin 28, La. Agr. Exp. Sta., p. 999. t See Report U. S. Comm. Agr., for 1879, p. 249. 388 INSECT PESTS OF FARM, GARDEN AND ORCHARD observed three generations. In central Texas the beetles hiber- nate over winter, but in south Texas they continue to breed in the bins during the winter. Control. — Dr. F. H. Chittenden (I.e.) recommends the follow- ing methods for control in addition to the quarantine measures which have been established by various states to prevent the spread of the beetle in shipments of infested potatoes. Rotation of crops, especially valuable since the weevil does not breed in crops other than the sweet potato and does not breed in any other plants except a few closely related weeds, is the first recom- Fig. 323. — The sweet-potato root-borer (Cylas fonnicarius): extreme left hand figure, adult beetle, with enlarged antennae at right; figure at left center, pupa; at right center, larva; at extreme right, portion of sweet- potato tuber channeled by borer- — all figures except the last considerably enlarged; natural sizes indicated by hair lines. (After Farmers' Bulletin, No. 26, U. S. Dept. Agr.) mendation. Clean culture, including the destruction of all refuse from infested fields, and the burning or feeding to hogs of all damaged potatoes. Removal of the seed beds as far as possible from the field where the potatoes are to be grown has also proven of great value in reducing the amount of damage. Dipping the plants, before setting, in a solution of lead arsenate and later, spraying with an arsenical, zinc arsenite being suggested as having given success, to kill the early appearing beetles, are also recommended. Prompt harvesting, as soon as the potatoes are ready, and the separation of damaged potatoes is necessary. Keep down volunteer plants upon which the weevils can breed. CHAPTER XX INSECTS INJURIOUS TO THE STRAWBERRY * The Strawberry Root-louse f If bare spots are found in the strawberry bed and the neigh- boring plants are unhealthy, the presence of the root-louse may be suspected, especially if ants are abundant around the plants. If present, the small dark green or blackish aphids will be found clustered on the roots and stems, caus- ing the plants to wither and die. The individual aphid is only about one- twentieth inch long, and deep bluish or greenish-black when mature, the young- er stages being Hghter, and somewhat pear-shaped as shown in Fig. 324. Injury by this pest was first noted in southern IlUnois in 1884 and a few years later it became troublesome in Ohio. In the late '90s it ruined many beds on the Fig. 324. — The strawberry Maryland-Delaware peninsula and be- ^T^'J?''^''- ^i^^'"'- ••^'""^^'' *' . . ^ VVeed) ; wingless viviparous came estabhshed m New Jersey. Since female of late summer — then it has become distributed on plants g^^eatly enlarged, throughout most of the states east of the Rockies, injury having been noted in New Hampshire, Michigan, Minnesota, Kansas, Texas, and Kentucky. Injury is most severe on Hght, sandy soils and the pest rarely becomes very troublesome on heaviey soils. Injury is also more or less periodic, the aphids almost disappearing after doing serious injury for two or three years. Fortunately the strawberry is the only food plant and the root- hce found on other crops are entirely different species. * See L. Bruner, Report Nebraska Horticultural Society, pp. 49-100; J. B. Smith, Bulletin 225, N. J. Agr. Exp. Sta.; A. L. Quaintance, Bulletin 42, Fla. Agr. Exp. Sta.; S. A. Forbes, 13th Report State Ent. of 111., pp. 60-180. ^ Aphis forbesi Weed. Family Aphididoe. See Sanderson, Bulletin 49, 12th, 13th and 14th Reports, Del. Agr. Exp. Sta. 389 390 INSECT PESTS OF FARM, GARDEN AND ORCHARD Lije History. — The winter is passed in the egg stage, the eggs being black and shining and located on the stems and on the midribs of the leaves. The eggs hatch early in the spring and the young aphids feed on the young leaves in the crown. This generation is composed of wingless females which give birth to Fig. 325. — Strawberry root-lice clustered on small rootlets from crown of plant — greatly enlarged. living young and this method of reproduction continues until fall when males appear and the eggs are again produced. Shortly after the aphids have become active the ants appear and carry many of the young aphids down and place them on the roots of the plants. This ant is the same as the one which harbors the corn-root aphis. (See page 152.) On the roots of the plant the aphids cause the most of the damage, weakening and even killing the plants. They are transferred from plant to plant by the ants in the underground stage while above ground winged forms which fly to fresh food plants appear from time to time. Control. — The aphid is largely kept in check by parasitic enemies similar to those described as attacking the "green-bug" INSECTS INJURIOUS TO THE STRAWBERRY 391 and so rarely becomes a serious pest or remains so for a period of years. The best method of avoiding loss is to set out uninfested plants on land as far removed from infested beds as possible. Plants can be freed from the lice by dipping them, after the Fig. 326. — Eggs of strawberry root-louse or P'ig. 327. — Strawberry root-lice which have leaf steiQ. been killed by parasites, with one of the little parasitic flieswhichhas justemerged . eggs have all hatched, in a solution of tobacco. Plants may also be freed from aphids by fumigation with hydrocyanic acid gas (see Delaware bulletin by the senior author). The aphids in an infested bed may be largely destroyed in the spring by scattering straw over the bed and burning before growth has started. There is little danger of injury to the plants if this is properly done. The Strawberry Crown-borer * Strawberry plants are often dwarfed or killed by a small white larva which mines out the interior of the crown, hollowing it out from the bases of the leaves to the larger roots. Usually but one grub is found in a plant, and it looks very much like a small * Tyloderma fragrarios Riley. Family Curculionidoe . See S. A. Forbes, 12th Report 111. State Ent., p. 64; 13th Report, p. 142; H. Garman, Bulletin 80, Ky. Agr. Exp. Sta.. n. 261. 392 INSECT PESTS OF FARM, GARDEN AND ORCHARD white grub as it lies curled in its burrow. It is only about one- quarter inch long, and legless, the body being white and the head yellowish brown. The adult beetle is a small snout-beetle about Fig. 328. — A Delaware strawberry bed in summer of 1900, showing injury, by the strawberry root-louse. one-fifth inch long, of a dark color, with head and thorax nearly black, and on each wing-cover are three black spots, the middle one being the largest and separated from the others by pale lines. According to Professor Garman the wings are too small to be used for flight and this doubtless ac- counts for the slow spread of the pest. Injury has been reported from Illinois, Ken- tucky, Missouri, and Neb- raska, but as the larvae might be readily shipped in plants, it is quite probable that it has become generally distributed but has not done sufficient injury to attract attention. Life History. — The beetles appear during the latter part of summer and fall and hibernate over winter in the soil, emerging early the next spring. The eggs have not been observed, but are Fig. 329. — The strawberry crown-borer {Ty- loderma fragraricB Riley): a, larva; 6, c, beetle — enlarged. (After Riley.) INSECTS INJURIOUS TO THE STRAWBERRY 393 undoubtedly laid on the crown between the bases of the leaves in late spring. The larvae develop in the crowns and become full grown by midsummer or August when they pupate in the cavities formed and the adult beetles emerge in late summer and fall. There seems to be but one generation a year. Old plants are worst injured, and runners formed late in the season are usually free from the pest, as eggs are probably not laid after June. Control. — Frequent rotation, plowing up the bed after one or two crops, will largely prevent the pest becoming established. Where the insect is well-established in old beds, it will be well to secure plants from beds known to be free from the pest and to plant new beds at some distance from the old ones. Infested beds should have the plants plowed out and raked up and burned as soon as possible after the fruit is harvested and before August. Owing to the fortunate fact that the beetle cannot fly ffom field to field, if the above measures are consistently carried out there should be no trouble in controlling the injury. Strawberry Rootworms * The larvae of three species of common leaf-beetles often feed upon the roots of the strawberry and are easily mistaken for the crown-borer or for small white grubs. They may be distinguished from the former by having three pairs of small thoracic legs just back of the head, and from the latter by their being much thicker. These rootworms are from one-eighth to one-sixth inch long, whitish, with brownish heads, and usually feed on the roots externally, though sometimes boring into them or the crown. Dr. Forbes * has indicated the structural differences by which they may be separated and shows that their life histories are quite dissimilar. "The larva of Colas-pis appears early in the season, and does its mischief chiefly in the months of April and May, the beetles beginning to emerge in June. That the eggs are laid in the preceding year is highly probable, in which case the species hibernates in the egg. Typophorus, on the other hand, certainly passes the winter as an adult, doubtless laying its eggs in spring, and making its principal attacks upon the plants in June and July, the beetles emerging in the latter part of * Typophorus canellus Fab., Colaspis brunnea Fab., Graphops pubescens Mels. Family Chrysomelidoe. See Forbes, I.e., p. 150. 394 INSECT PESTS OF FARM, GARDEN AND ORCHARD July and early in August. Graphops hibernates in the larval con- dition, pupates in the spring, and emerges in May and June. The eggs are probably laid in July, and the larvae make their attack upon the plant in August and Sep- tember. . . " — Forbes. Thus the larvae of the three species may be found throughout the season where all occur, The beetles are about one-eighth inch long and may be distinguished as follows, according t o Bruner: "Colapsis hrun- nea is usually of a yel- lowish clay color, but ranges to yellowish- brown. The body is smooth but not shining. Typophorus canellus is usually shiny, black above, varying to brown, with four black blotches on the wing-covers. The legs and antennae are always pale. Graphops puhescens is either green or purple with a bronze metallic sheen, and has the entire body more or less covered with a gray pubescence." The pupae are all found in earthen cells among the roots of the plants . The beetles of Fig. 330.— The strawberry root-borer (Typo- allthreespeciesfeedonthe phorus canellus Fab.) : adult and larva — very foliage and when numer- greatly enlarged, hairline at right of beetle .„ shows natural size. (After Pettit.) OUS Will attract attention. INSECTS INJURIOUS TO THE STRAWBERRY 395 Control. — Whenever the plants are not in fruit, the beetles may be destroyed by spraying with 3 pounds of arsenate of lead per barrel, preferably appKed with Bordeaux mixture. Where the plants are customarily sprayed with Bordeaux mix- ture for leaf diseases arsenicals may be added and will probably control this and other strawberry pests. Badly infested fields should be plowed under deeply as soon as the crop is secured and new beds should be planted at some distance from them. The Strawberry Saw-fly * Occasionally the strawberry leaves are skeletonized by yellow- ish or greenish "worms" one-half to three-quarters of an inch long when full grown. The head is yellow with two brown spots on the side and one or two on top, and there are eight pairs of yel- lowish abdominal pro- legs, in addition to the true thoracic legs, which at once disting- uish the saw-fly larvae from true caterpillars. The adult saw-flies are about one-quarter inch long, with two pairs of blackish, well-veined Fig. 331.— The strawberry saw-fly (Harpiphorus wings which are folded ^'T^f "« Norton) : 1, 2, pupa; 3, 5 adult flies; ,, , , , 4, 6, larvae; 7, cocoon; 9, egg— all enlarged, over the abdomen when (After Riley.) at rest. The body is black, with a row of lighter spots on either side of the abdomen. The flies emerge in late April in Missouri or about a fortnight before the plants flower freely. The eggs are inserted just beneath the epidermis of the leaves and hatch in about two weeks, just as the plants begin to bloom. The larvte eat holes in the leaves and "where numerous, they will defoliate the plants to such an extent as to injure greatly or completely destroy the crop of fruit, and may even kill the plants them- * Harpiphorus maculatus Norton. Family Tenthredinidoe. See J. M Stedman, Bulletin 54, Mo. Agr. Exp. Sta. 396 INSECT PESTS OF FARM, GARDEN AND ORCHARD selves." When at rest or disturbed the larvae coil themselves up in a spiral on the under side of the leaf as shown in Fig. 331, but if suddenly disturbed they will often drop to the ground. By the last of May the larvae are full grown and enter the soil, where they make small cells, lined with a gummy substance, and in them hibernate until the next spring, when they pupate and the adult flies emerge. Injury by the saw-fly has been reported from the Northern and Central States from Missouri and Nebraska to Maine. A nearly related species * with almost identical habits has done similar injury in Iowa, Illinois and Indiana. The larvae are a deep green, much wrinkled, with a blackish stripe along the back and an obscure blackish stripe on each side, and the head brown. Control. — Inasmuch as the larvae commence to hatch just as blooming commences Professor Stedman has shown by experi- ments that spraying the foliage at this time with arsenicals will entirely protect it from the larvae. If they commence work before their presence is noticed, the fohage may be sprayed until the first berries are about one-third grown without any danger of poisoning them. Hellebore, 1 pound to 3 gallons of water was also effective, as was dusting with pyrethrum. Although there may be some prejudice against the use of arsen- icals, where properly apphed at the right time there is no reason why they should not be used. The Strawberry Leaf-roller f Where leaves are found folded together, many of them being dry and brown, the small green caterpillars found feeding within the folds are probably those of the Strawberry Leaf-roller. It is a European insect, though it is not injurious there, and the first record of injury in this country was made by Dr. C. V. Riley in 1869, who stated that in one place in Missouri it destroyed ten acres so completely as not to leave enough plants to set a half acre. "Since that time," says Dr. J. B. Smith, "the insect has been frequently mentioned as injurious in many parts of the * Monostegia ignota Norton. See F. W. Mally, "Insect Life," Vol. II, p. 137. t Ancylis comptana Frohl. Family Tortricidoe. See J. B. Smith, Bulle- tins 149 and 225, N. J. Agr. Exp. Sta. INSECTS INJURIOUS TO THE STRAWBERRY 397 country, but rarely is it troublesome for more than a year or two in succession. It is always inclined to be local and its ravages do not often extend over wide areas." Life History. — The moths appear in the strawberry fields during early May in New Jersey and commence to lay eggs, the moths being found in the fields for about a month. The eggs are laid on the under surface of the half-grown leaves. They are broadly oval or round, much flattened, of a pale green color and about one-fiftieth inch in diameter. They are laid in the fine netting of the leaf, in which they are seen with great difficulty. The larvae hatch in from five to seven days. The young cater- pillar feeds on the upper surface of the leaf for a day or two, Fig. 332. — The strawberry leaf-roller moth (Anajlis comptana Frohl.) — enlarged. (After J. B. Smith.) eating into and along the midrib to weaken it. The young larva is at first a hght green color with a large head and long hair, which becomes less noticeable as it grows. It soon commences to draw the edges of the leaf together, folding the upper surface on the midrib, holding it together by numerous strands of fine silk. The insect then spins a partial tube or Hning inside, in which it remains until the moth develops. Unless disturbed the larva does not leave this folded leaf, and all the feeding is done out of the reach of sprays. The larva becomes full grown in about four weeks, when it is about half an inch long and of a dark-green color, until just before pupation, when it becomes more yellowish. The head and thoracic shield are shining brown, and the small body tubercles are slightly lighter. The larvae are slender and very active, wriggling violently when disturbed or taken from their webs. " Pupation occurs in the tube made by the larva. The pupa itself is brownish-yellow, without obvious processes or protuber- 398 INSECT PESTS OF FARM, GARDEN AND ORCHARD ances, and a little more than one-fourth an inch long." The pupal stage lasts about ten days, thus giving about forty-two to fifty days for the complete life cycle from egg to adult. The moths of the second brood appear late in June and during July. This brood is much more abundant on blackberry and raspberry than on strawberry plants. The moths of the third Fig. 333.— Strawberry leaf folded by the leaf-roller. (After J. B. Smith.) brood appear in August. They are comparatively few in number and also seem to prefer blackberry and raspberry. Young larvae are, however, to be found on strawberries in September. "Accord- ing to the account given by Riley, the larvae change to pupas late in September and remain during the winter in that state." Dr. Smith states that he has not observed this personally. In Delaware we have found full-grown larvae in folded leaves in midwinter, so that possibly some of them at least do not pupate until spring. " The adult moth is small, measuring with expanded wings about two-fifths of an inch. In general color it is somewhat INSECTS INJURIOUS TO THE STRAWBERRY 399 reddish-brown, the fore-wings streaked and spotted with black and white as shown in the illustration. When the wings are folded, the dark area at the base forms a somewhat conspicuous deeper brown patch in the middle of the back. The hind-wings are of a soft, dark smoky gray, and both wings have long fringes. The insects fly readily during the middle of the day, and run rapidly on the leaves, diving to the under side or into a fold so quickly that it requires close watching to follow their move- ments. From the fact that newly set fields are often infested, it is probable that they fly for some distance to seek their food plant." — Smith. "A badly infested strawberry-patch begins to look scorched early in June, and before the middle of that month appears ns if a fire had been over it. The fruit, deprived of the food prepared by the foliage, stops growth, ripens undersized or prematurely, or shrivels up altogether, even before it colors." "Often every lobe on a leaf will be folded, and occasionally, when infested leaves cover or touch, an irregular mass of foliage is bundled up in which as many as six or eight larvae may be found. "On blackberry not so large a part of the leaf is involved, and frequently only the tip of one of the leaflets is webbed up. Furthermore, the injury is more local, and only that part that is actually eaten is harmed. The total amount of food really devoured is very small, and were it not for the manner of feeding, which interferes with the nutrition of the leaf, the strawberry could easily spare tissue for all these caterpillars that ever infest it. On the raspberry the habit is yet difi'erent. Here the larva gets into a partly opened tip and webs it together so securely as to check growth. The actual eating shows a rusty space on the upper side of the leaf, and not much more harm is done." Control. — As stated above, the young caterpillar, just after it is hatched, goes to the upper surface of the leaf and feeds there exposed for a day or two before folding the leaf. "It must be the object of the grower to poison the foliage so early in the season that when the young caterpillar starts feeding, it can find no fohage it can safely eat. Therefore, as soon as moths are found flying in fair numbers, spray with arsenate of lead. Experiments in New Jersey have shown that complete control may be secured with one application if this is thorough and applied at the right time. 400 INSECT PESTS OF FARM, GARDEN AND ORCHARD "If for any reason no timely applications were made and the fields become badly infested, nothing practical can be done until the crop is off. Then mow the beds, rake off all the fohage, and burn it. You will burn with it all the larvae and pupae that are then unchanged. This lessens the number of moths that come to maturity and so helps somewhat for the following year." The Strawberry Weevil * If the buds appear to be "stung" so that they wither, and if many of the stems are cut so that the buds drop to the ground, the strawberry weevil is the probable cause of the damage. This little weevil is only about one-tenth inch long and so is often unnoticed, and the loss is attributed to other causes. The weevil varies from nearly black to dull red, with a dark spot just back of the centre of each wing-cover. The head is prolonged into a slender curved snout, about half as long as the body. The species is found in most of the States east of the Rockies, but injury has been mosts evere in the Middle and Northern States. Life History. — The weevils hibernate over winter and appear in spring a few days be- fore the earliest staminate varieties com- mence to bloom. Others emerge during the Fig. 334. — The straw- , ^u u ^ iu a • • • j berry weevil (Antho- ^^xt month, but the most injury is done nomus signatus Say.)— within the next two weeks. The injury is enlarged. (After Riley , T_.ir i u-i, x iiui and Chittenden U. S. done by the females, which eat small holes Dept. Agr.) through the outer husk or corolla of nearly matured buds, and in these little cavities deposit their eggs. The stem of the bud is then cut so that it hangs by a mere thread and soon falls to the ground. By severing the stem the development of the bud is arrested, thus preventing the outer covering from un- folding and holding the eggs and larvae in the pollen, on which they feed, and by falling to the ground the bud remains moist and will not dry up as it would on the stem. The eggs hatch in from six * Anthonomus signatus Say. Family Curculionidoe. See F. H. Chitten- den, Circular 21, Div. Ent., U. S. Dept. Agr.; J. B. Smith, Bulletin 225, N. J. Agr. Exp. Sta. INSECTS INJURIOUS TO THE STRAWBERRY 401 to seven days and the small whitish larvae feed on the pollen and later on the harder parts of the buds. Three or four weeks are re- quired for a larva to become full grown. It then forms a little cell in the bud, in which the pupal stage is passed in from five to eight days, when the adult beetle emerges and cuts its way out. Thus the complete life cycle occupies about a month and in the District of Columbia the new generation of beetles appears during June. They are frequently found in large numbers on strawberry flowers and on those of the horse mint {Monarda fistulosa), but the beetles soon seek hibernating quarters, there being but one generation a year. Control. — As the larvae feed upon the pollen of the buds of staminate varieties, the staminate varieties are most injured, and injury may be avoided by growing as few rows of staminate varieties as are necessary Fig. 335.— The strawberry weevil: a, 6, spray for fertilizing the rest of the ^^^^^^s To^'k ^" b"^ ^1 stem-natural ^ size; c, outline of egg; a, larva; e, head oi bed. Indeed the very early same; /, pupa; g, bud opened to show egg ^tnminafp vnriptip'=! mio-bf on left and punctures made by snout of Staminate vaneties mignt beetle through petals. (After Chittenden, be used as a trap crop for U. S. Dept. Agr.) attracting the weevils, which might be destroyed by covering the rows with straw and burning, or possibly by spraying with arsenicals. By planting rows of early varieties, which flower freely and produce an abundance of pollen near woods and fence-rows where the beetles have hibernated and appear first, they might be effectively trapped, and then destroyed. Although the larvae cannot be reached with any insecticide, the beetles feed more or less on the buds and foliage, and further experiments should be made in spraying for them with arsenicals. Dr. T. J. Headlee (Circulars 56 and 65, New Jersey Agr. Exp. Station) recommends dusting the plants with arsenate of lead powder one pound mixed with five pounds sulphur dust. On a large 402 INSECT PESTS OF FARM, GARDEN AND ORCHARD scale this should be applied with power dusters as the hand dusters have not proven so successful. Begin applications as soon as the weevils appear, not later than the first of May. Lead arsenate appHed as a spray has seemed to give good control in some smaller tests and should be at least as effective as the dust. The destruction of all trash and rubbish in and around the fields during the winter will destroy some of the hibernating weevils, and it will be well to avoid mulching the beds where the beetle is troublesome, if the mulch is not absolutely neces- sary, as it furnishes them the best hibernating quarters. CHAPTER XXI INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY * The Raspberry Root-borer f The larvae of the Raspberry Root-borer make tunnels in the roots and lower stems of raspberry and blackberry, sometimes completely girdhng the stem at the crown, so that the name of blackberry crown-borer has also been used. The full-grown larva is from 1 to 1^ inches long, yellowish- white, with brownish head, and the tips of the small thoracic legs also brownish. The parent insect is one of the clear-winged moths, which fly by day and closely resemble wasps, and is nearly related to the peach- and squash-borers. The female is much the larger and is shown natural size in Fig. 336. The body is black with yellow rings, and the legs are yellowish. The wings are transparent except a bronze- brown margin and a narrow band across the fore-wings about one-third from the tip. Life History. — The moths appear in late August and September and the females deposit their eggs upon the lower edge of the leaves. The egg is oval, about one- sixteenth inch long, deep brownish-red in color. A female lays about 140 eggs, which are deposited singly. They hatch in Sep- tember and the young larvae crawl down the stems and bore under the bark. Here they may either make a small blister- * See F. M. Webster, Bulletin 45, Ohio Agr. Exp. Sta.; J. B. Smith, 12th Report N. J. Agr. Exp. Sta. t Bembecia maerginata Harr. Family Sesiidce. See J. B. Smith, Bulletin N., N. J. Agr. Exp. Sta., p. 9; W. H. Lawrence, Bulletin 63, Wash. Agr. Exp. Sta. 403 Fig. 336.— The raspberry root-borer {Bembecia marginata Harr.) : a, male moth; h, female moth — natural size. (After Riley.) 404 INSECT PESTS OF FARM, GARDEN AND ORCHARD like cavity and hibernate over winter, or if hatched earlier they may feed on the sap wood or occasionally bore into the stem and become one-quarter inch or more long before winter. The next season the larvae bore in the lower stem and roots, but the nature of the injury differs as observed in different places. In New Jersey, Dr. J. B. Smith states that the larvae girdle the stem at the crown, causing the plants to die. In spring they aban- don the old wood and attack new shoots, but he observed none entering the stem. In Washington, the infested plants seldom show any signs of the pres- ence of the borers other than a poor growth, though occasionally a few hills will die where the roots have been badly riddled by the larvae, the injury being mostly in the roots. "The borer," according to Law- rence, "first enters the roots and tunnels through them promiscuously until the second spring, and then directs its course upward, entering and eating the pith of the cane for a distance of ■c oo-r T> u t- u /T> I. • one to five inches." At the Fig. 337. — Raspberry root-borer {Bemhecia ^ ^ '^ marginata Harr.): a, female and male end of the first summer the larva) full grown; 6 male and female j j one-half to three- pupa;; c, lemale, and a, male moths rest- ing on leaf; e, e, eggs — slightly reduced, quarters inch long. By the (After Lawrence.) middle of the second sum- mer the larva is full-grown and bores an exit hole through the wood and bark just above the crown, leaving the hole covered by INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY 405 the epidermis only The larva then descends into the tunnel and pupates. The pupa is about three-quarters inch long, reddish-brown the head bears a sharp-pointed process, and each abdominal segment bears two transverse rows of sharp teeth. By means of these the pupa wriggles itself out of the burrow until it pro- j ects from the aperture, and the adult moth emerges. This insect occurs throughout the Middle and Northern States east of the Fig. 33X. — \\'ork of the raspberry root-borer: a, two canes with empty pupa cases projecting from burrows; h, canes showing opening of tunnel through which pupse have wriggled out. (After Lawrence.) Rockies, is injurious in Washington and around Vancouver, B. C, and has been observed in Colorado and New Mexico. Control. — The only method of control is to pull up the infested canes, root and branch, and destroy them by burning. As this is the only means of controlling several pests of cane fruits, the canes should always be gone over in spring and those showing any injury removed. The Raspberry Cane-borer * If the tips of the young shoots of raspberry and blackberry are found withered and djang they have probably been girdled by the cane-borer. The adult beetle is about one-half inch long, with a slender, cylindrical body and long antennae, and of a deep black color except the prothorax, which is yellow with two or three black spots, though these are sometimes lacking. * Oberea himaculata Oliv. Family Cerambycidoe. See Comstock and Slingerland, Bulletin 23, Cornell Univ. Agr. Exp. Sta., p. 122. 406 INSECT PESTS OF FARM, GARDEN AND ORCHARD Life History. — The beetles appear in early summer and the females girdle the young tips by cutting two rings around the shoot about an inch apart, causing the tip to wither and droop. Between these rings will be found a small dark spot where the female has inserted an egg in the cane. A rather large, elliptical, yellow egg is placed in the pith of the cane and in a few days hatches into a small white grub. The larvse burrow downward through the pith of the stems, the burrows winding from side to side and frequently penetrating the side of the stem, where openings are made every few inches, through which long strings Fig. 339. — The raspberry cane-borer (Oberea bimaculata Oliv.): adult, larva, and larval castings — all enlarged. (After Lugger.) of excrement are cast out. By fall they are bored to the base of the cane, in which they hibernate over winter. The full- grown larva is about one inch long, of a dull yellow color, with a small dark-brown head. The body is quite cyUndrical and the segments constricted as shown in Fig. 339. The pupal stage is passed in the burrow during the spring. Although it has been generally assumed that the life cycle is passed in a single year, there is some reason for believing that two years may be required. The eggs are usually laid only in the young tips, but Comstock and Slingerland found larvse somewhat over half grown which had made burrows only two inches long in old canes in late July, and Professor Webster has secured larvse over half grown in early INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY 407 June. Possibly, therefore, two years may be required for maturing a generation, and the fact that the pest does not increase may be due to the cutting back of the injured tips of the young canes. Control. — As soon as the tips are seen to droop they should be cut off below the point girdled and burned. When the entire canes die from the effect of being tunneled, they should be cut in late summer before the larvae have gone to the base to hiber- FiG. 340. — Egg of the rasp- berry cane-borer, showing girdling of cane. (Photo by Headlee.) Fig. 341. — Young grubs and exit hole of the raspberry cane-borer. (Photo by Headlee.) nate. Where such measures are practised the pest may be effec- tively controlled. The Striped Tree-Cricket * Professor Parrott has recently shown in an interesting bulletin from the New York station that the tree-cricket which most frequently attacks the raspberry is not, as had been supposed, the snowy tree-cricket (Oecanthus niveus DeG.) but a different species, the one named above. The snowy cricket confines its attentions more to apple and other tree fruits. * Oecanthus nigricornis Walker. Family Gryllidoe. See Parrott and Ful- ton, Bulletin 388, N. Y. (Geneva) Agr. Exp. Sta. 408 INSECT PESTS OF FARM, GARDEN AND ORCHARD Fig. 342. — The snowy tree- cricket (Oecanthus nigricornis Walker): a, female; 6, male. (After Summers.) When the canes fail to put out leaves in the spring and are found to be dead, this often proves to be due to a long ragged wound like that shown in Fig. 343a. "If the rough surface of the wound be cut away with a knife, the injury will be found to consist of a longitudinal series of punctures placed close to- gether. By splitting the cane the nature of the injury can be seen even better. Such a section is shown at h in the figure. The punctures extend through the woody part of the cane in- to the pith, and here there is in each an oblong, cylindrical egg. One of these eggs is represented enlarged at c. The insect which thus seriously injures the raspberry canes in preparing a safe receptacle for its eggs is a deUcate greenish-white cricket. Fig. 342 represents the male. Its wing-covers are crossed by oblique thickenings or ribs, which form part of the musical apparatus of the insect. The female, Fig. 342a, differs somewhat in appearance from the fact that the wing-covers are wrapped closely about the body, making the insect much narrower than her mate." (Comstock and Slinger- land.) The cry of these tree-crickets is well known, sounding much Hke that of the katy- did, but is less rasping and more monoton- ous. They are heard in early evening until well into the night, and in the North their chirp is the most noticeable of all the insect noises at that time. This species is quite yig. 343-Raspberrystem widely distributed and frequently oviposits injured by the snowy in the tender twigs of fruit trees, which are similarly injured, and in the stalks of cotton and various woody weeds. Life History. — The eggs are laid in the fall and hatch in the late spring. The nymphs tree-cricket: a, wound made by egg - punc- tures; h, longitudinal section through same showing eggs in path; c, egg enlarged; d, cap of egg, more enlarged. (After Riley.) INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY 409 feed mostly on plant-lice and other insects, as do the adults, and though they occasionally nibble foliage, they are seldom in- jurious, and both nymphs and adults must be regarded as beneficial as far as their feeding habits are concerned. In the North the nymphs become full grown late in July, and there is but one generation a year, but in Texas they become full grown late in June and eggs laid in early July hatch in about two weeks; nymphs are common in late summer, and the adults of the second generation in fall. Control. — By examining the canes as soon as the foliage starts, those injured may be detected and should be cut out and burned. If not numerous enough to do appreciable damage they may be ignored. The Red-necked Cane-borer * Sometimes the canes of raspberry and blackberry are found with one or more elongate galls, not over one-third larger in diameter than the normal cane, and usually with numerous sHts, which have been called the ' ' gouty gall. ' ' The infested shoots may throw out leaves, but they rarely rip- en fruit and usually die during the season. By opening the gall it will be found that only the bark has been injured by a spiral channel which girdles the stem and causes the gall-Kke thickening of the bark. Above the swel- ling evidence will be found of the borer's work in the pith, and from one to six inches above the gall the slender white larve Fig. 344 -The red-necked cane-borer (^^nZ^s ... ruficolas L ab.) : beetle, larva and gall — all Will be found at work. much enlarged. (After Riley.) * Agrilus ruficollis Feab. Family Buprestidce. See J. B. Smith, 12th Report N. J. Agr. Exp. Sta., p. 373; and F. M. Webster, I.e., p. 000. 410 INSECT PESTS OF FARM, GARDEN AND ORCHARD There seems to be considerable difference in the susceptibility of varieties, Dr. Smith observing that the " Wilson" and black- cap raspberries are badly infested, while the "Missouri Mam- moth" and others were unharmed. Life History. — The eggs are laid in June and the young larva enters the bark at the axil of a leaf-stem, and eats around the stem in a long spiral. By early August the galls commence to form where the bark has been girdled, though sometimes no gall results from the injury, and the larvae mine into the pith. The larvae probably become practically full grown in the fall and remain in their burrows over winter, in which they transform to pupae in late April, in New Jersey, and the beetles emerge in late May and June. The parent beetle is not over one-third inch long, flattened, with a small wide head, and tapers at the tip of the abdomen. It has brown- ish-black wing-covers with a bronzy lustre, and the neck and thorax are coppery-red or brassy. The full-grown larva is five-eighths to three-quarters inch long, with a small brown head, a much- expanded prothorax which looks like the head, and a slender, cylindrical, white body, surmounted by two slender brown horns at the tip of the abdomen. This cane-borer is a native pest, very common in wild rasp- berries and blackberries, and occurs generally throughout the country. Control. — Obviously it may be readily controlled by cutting off the infested canes below the galls and burning them. This should be done any time before May. Where wild canes are infested near those cultivated they should be included in the pruning. -t^ Fig. 345. — Work of the red-necked cane-borer: a, tracks of young larvae the bark sliced away to show burrows and forming gall ridges; 6, sec- tion through galls on main cane and lateral showing track of larva through bark and pith and pupal cell. (After J. B. Smith.) INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY 411 The Blackberry Gall-maker * The so-called "pithy gall" of the blackberry is an elongated, pithy swelHng from one to three inches long and nearly an inch in diameter, red or reddish-brown, with the surface divided by deep longitudinal furrows into four or five ridges or parts. The gall is caused by the larvse of a small black gall-fly, which is about one-twelfth inch long, with red feet and antennae and four transparent wings, almost lacking wing-veins. The insect passes the winter in the larval stage in the galls, and if one be opened at that season, there will be found about the middle a number of cells about one- eighth inch long, each of which contains a single larva. The larva "is about one-tenth inch long, white, with the mouth- parts reddish, and the breathing pores and an oval spot on each side behind the head of the same color." They change to pupae in spring and the flies appear Fig. .346.— The pitliy-gall of the blackberry: a, ^ rp/ 1 gall; 0, section oi same showing larvsB in cells; a little later. 1 hough c, larva enlarged and natural size; d, pupa, this gall is also very com- (After Riley.) mon on wild canes it rarely does much injury. Control. — The affected canes should be cut and burned during the winter. The Raspberry-cane Maggot f The tips of young raspberry shoots sometimes droop and wilt in the spring in much the same manner as when affected by the * Diastrophus turgidus Bass. Family Cynipidcp. t Phorbia rubivora Coquillet. Family Anthomyidoe. See Slingerland, Bulletin 126, Cornell Univ. Agr. Exp. Sta., p. 54; W. H. Lawrence, Bulletin 62, Wash. Agr. Exp. Sta. 412 INSECT PESTS OF FARM, GARDEN AND ORCHARD cane-borer later in the season, and though blackberry shoots are similarly affected they usually recover, but bear small gall-like swellings Hke those shown in Fig. 348. This is the work of a Fig. 347. — The raspberry cane-maggot {Phorbia rubiuora Coquillet) : a, adult female fly; much enlarged; b, raspiaerry shoots girdled by the maggot, natural size; c, egg much enlarged; d, tips of shoots each bearing an egg in natural position in the leaf axils, natural size. (After Slingerland.) small white maggot, nearly related to and looking much the same as the cabbage-maggot which girdles the inner bark of the stem. INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY 413 Injury has been observed in New York, Canada, Michigan, Pennsylvania, and recently it has become a serious pest in Wash- ington, so that it is undoubtedly much more widely distributed than the records indicate. The parent fly, shown in Fig. 347, is grayish-black, much resembling the house-fly, but slightly smaller. Life History.— The flies appear in April and deposit their eggs as soon as the shoots are well above ground, continuing until early June. The white egg (Fig. 347, c) is elongate, about one- fifteenth inch long, and is laid in the axil of a young leaf at the tip of a shoot (Fig. 347, d). The egg hatches in a few days, and the little maggot burrows into the pith of the shoot, leav- ing a conspicuous entrance hole, which becomes blackish. It tunnels downward, making a small tortuous channel, and after boring for a few days about half way down the shoot, it works its way out to just beneath the bark and tunnels around the shoot, often in a spiral, so as to girdle it completely, and usually eats a small hole through the bark at this point. The maggot continues to feed on the pith at this point so as nearly to sever the shoot, the tip of which soon wilts and droops, turning a deep blue color. On blackberry shoots, however, the bark is so thick that although the tip droops for a few days, it usually revives and the girdling forms a circular, gall-like swelling, though even blackberries are often killed. Affected shoots usually branch from below the girdled point, making a bushy growth. Lawrence states that later in the season lateral shoots are also attacked. He also observes that maggots never develop in living canes. The maggot continues to burrow downward in the pith and becomes full grown in June, when it pupates at the lower end of the burrow. The puparia are to be found in the lower part of the affected stalk in June and July, but the adult flies do not emerge until the next spring. Control. — As soon as the young tips are seen to droop they Fig. 348. — Gall-like swelling one living blackberry canes caused by the rasp- berry cane-maggot. (After Lawrence.) 414 INSECT PESTS OF FARM, GARDEN AND ORCHARD should be cut off several inches below the girdled point and burned. This may be done best late in May or in June after all the eggs are laid. The Raspberry Saw-fly * Occasionally raspberry leaves, as well as those of blackberry and dewberry, are skeletonized in May by small green, spiny saw-fly larvae, which sometimes quite defoliate the plant. Such injury has been commonly noted in the Eastern and Central States. The adult female is a typical saw-fly about one-quarter inch long and with a wing expanse of one-half inch. The body and wings are black except the second and sixth abdominal seg- ments, which are yellowish-white, and the under side is rusty. The male is somewhat smaller and is entirely black except the shoulders, which are yellowish-white. Life History. — The adults appear about the middle of May in central New York, and the females deposit their eggs late in that month. The eggs are inserted just under the cuticle of the under surface of the leaf, and the tissue around them turns yellowish, so that infested leaves soon become spotted on the upper surface. The egg is nearly pear-shaped, yellowish-white, about one-twentieth inch long, and hatches in seven to ten days. As many as twenty-four eggs have been observed in a single leaf, and frequently the leaves are so spotted as to be readily recognized. The young larva is about one-twelfth inch long, yellowish-white or pale yellowish-green and well covered with spiny tubercles, the spines being first white and later dark brown. The young larvae feed on the soft parts of the leaf, but as they grow older all but the midrib and larger veins are devoured. The mature larva is about three- quarters inch long, from light yellowish-green to darkgreen, closely simulating the color of the foliage, and the body is covered with transverse rows of tubercles, bearing a varying number of strong, barbed spines, which are dark brown on the back and pale green or white along the sides. The larva feeds for about ten days and then enters the soil for from two to three inches and thete con- structs a small oval cocoon about one third inch long, which looks like a pellet of earth, being formed of a brown mucilaginous sub- * Monophadnus ruhi Harris. Family TenthredinidoB. See V. H. Lowe, Bulletin 150, N. Y. Agr. Exp. Sta. INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY 4 1 5 r i stance, interwoven with coarse strands of silk, to which particles of earth adhere. The larva then hibernates until the next spring, when it transforms to the pupa and in a few days the adult ap- pears, usually early in May, Control. — By suddenly jarring or shaking the bushes the larvse will be shaken to the soil. On light soils this habit may y Fig. 349. — The raspberry saw-fly (Monophadnus rubi Harr.) : a, male; h, female; c, egg blisters on leaf; d, larva; e, cocoons — all much enlarged. (After Lowe.) be utilized for their destruction by jarring them to the ground and following with cultivators so as to bury the larvae in the loose soil. This will be particularly applicable in hot weather, if the soil is hot and dusty, when most of the larvse will be killed before regaining the plants. By frequent cultivation in late summer or fall the cocoons might be brought to the surface and some of the larvse might be thus killed during the winter, though 416 INSECT PESTS OF FARM, GARDEN AND ORCHARD this needs testing, as they are fairly well protected. The larvae may be readily killed with arsenical sprays, and if arsenate of lead were applied at the rate of 3 pounds per barrel just as the plants commence to flower, it would undoubtedly control the pest with no possibility of spotting the fruit, or Paris green with Bordeaux mixture might be used in the same way. If careful watch is kept for the pest it can probably be detected in time to apply the arsenicals, which will be much the easiest and most effective to use, but if not observed until the canes are fruiting they should be sprayed with hellebore, 1 ounce to 1 gallon of water. Hellebore may be dusted on the plants mixed with twice its weight of flour, but the spraying may be done more thoroughly. The Raspberry B3rturus * The Raspberry Byturus is a small brown beetle belonging to the same family as the larder and carpet beetles, most of which feed on animal matter. It is about one-seventh inch long, red- dish-yellow or reddish-brown, and covered with a thick coat of pale, tawny hairs. The beetles appear about the midde of May in northern Ohio. They feed on the tender foliage and Fig. 350. — Larva and adult of the , • . .^ n ■, i i raspberry byturus— enlarged. (After eat mto the flower buds, and Goodwin.) sometimes emerge in such numbers that the young foliage is skeletonized and many of the flower buds do not develop. Though the eggs are laid in June, they have not been observed. The larvse appear in late June and July and feed in the fleshy head on which the berry is born, caus- ing the affected berries to ripen earlier, making them small and unfit for market. Furthermore the little larvae not infrequently remain in the cup of the berry, which necessitates picking the berries over and injures their sale. The larva is about one- quarter inch long, rather plump and cyhndrical, and tapering at each end. The body is white, but each segment is marked across the back with a broad, tawny yellow band, and nunierous * Byturus unicolor Say. Family DermestidcB. See W. H. Goodwin, Bulletin 202, Ohio Agr. Exp. Sta. INSECTS INJURIOUS TO RASPBERRY AND BLACKBERRY 417 short white hairs. When full grown the larva drops to the ground and forms an earthen cell just beneath the surface, in which it transforms to a yellowish pupa, from which the beetle emerges the next spring. Only red raspberries seem to be affected, and some varieties are particularly injured. The insect has been Fig. 351. — ^Early ripening berries, the smaller ones infested with Byturus larvae. (After Goodwin.) reported as injurious from Minnesota to Massachusetts and in Ontario. Control — Inasmuch as the beetles feed freely on the foliage before ovipositing they may be destroyed by sprajdng the leaves with arsenate of lead. Mr. Goodwin has shown that where foliage was sprayed with 4 pounds per barrel, that three-fourths of the subsequent injury to the berries by the larvae was pre- vented by the destruction of the beetles, and the injury to the flower buds was also lessened. Thorough cultivation in the fall close around tne bushes will probably destroy many of the pupae by exposing them to winter weather. CHAPTER XXII INSECTS INJURIOUS TO THE CURRANT AND GOOSEBERRY. The Imported Currant-borer * One of the worst pests of the currant and gooseberry is the borer, v/hich tunnels out the canes and where abundant frequently kills the plants. It is a European insect which has spread to Fig. 352. — The imported currant-borer (Sesia iipuliformis Clerck): moth, larva, and empty pupal skin left protruding from burrow. (After Lugger.) all parts of this country where these fruits are grown. The adult is one of the clear-winged moths and with the larva is very similar in appearance and habits to the raspberry root-borer The moth is about one-half inch long with a wing-expanse of three-quarters inch. The body is black with a steel-blue lustre, with a bright yellow band around the neck and three yellow bands across the abdomen, which bears a large tuft of long scales at the tip. The wings are clear except for a margin of blackish scales and a band across the fore-wings about one-third from the tip. * Sesia tipuliformis Clerck. Family SesiidoE. See Lugger, 1st Report- Minn. State Entomologist, p. 184. 418 INSECTS INJURIOUS TO CURRANT AND GOOSEBERRY 419 Life History. — The moths appear in June and deposit their small globular, brown eggs in the axils of the leaves next the canes, or under scales or in cracks of the canes. The young caterpillars bore into the pith of the canes, which they tunnel out, and are about half grown by winter, when they descend to the bottom of the burrows and hibernate. In the spring they con- tinue their work and become full grown by May. The full- grown larva is slightly over one-half inch long, of a yellowish color, with brown head, and with numerous small tubercles over the body. It cuts a hole through the side of the burrow, which it closes with small chippings, and then transforms to the pupa. When the moth is ready to emerge the pupa wriggles itself partly out of the burrow by means of the strong spines on the abdomen, and the moth comes forth. Affected canes can be recognized by the dwarfed and yellow foliage and the general unhealthy appearance of the plant, and if not removed will usually die during the season. Control. — The only method of control is to keep all the old wood removed and to cut out and burn all affected canes in fall or early spring, whenever the injury may best be detected. The Currant-stem Girdler * In late spring, after the young currant-shoots have reached a growth of several inches, two or three inches of the tips some- times wilt, and fall over and hang suspended or drop to the ground. If examination shows that the tip has been girdled by several sharp cuts, it is probably the work of the Currant-stem Girdler. It is a native insect which was first described from Massachusetts, and has also been found injurious in Rhode Island, Canada, Ohio and Michigan, but has been most troublesome in New York. It has also been noted as a pest of willow and poplar in Mary- land, and of basket willow in Kentucky, Indiana, and Ohio, so that it is doubtless quite generally distributed. The adult insect is a slender saw-fly with shining black body and light brownish legs, shown natural size in Fig. 353a. The male is smaller and has a brownish-yellow abdomen, while in the female the first * Janus integer Norton. Family Tenthredinidce. See Slingerland, Bul- letin 126, Cornell Univ. Agr. Exp. Sta.; F. H. Chittenden, Bulletin No. 46, Bureau of Forestry, pp. 68-70. 1' Fig. 353. — The currant stem-girdler (Janus integer Norton): a, female at work girdling a currant stem — natural size; b, girdled portion of stem much enlarged to show character of girdle; c, stem cut open to show egg; d, egg — much enlarged. (After Slingerland.) 420 INSECTS INJURIOUS TO CURRANT AND GOOSEBERRY 421 half of the abdomen is reddish-orange and the rest is black. The adults are abroad in May, but are very shy and are seldom seen. They are saw-flies in the truest sense of that term, for the female makes most effective use of her saw-like ovipositor, as has been very interestingly described and illustrated by Professor Shnger- land. The ovipositor is thrust into the cane for its whole length, and through it the egg is deposited in the pith. The egg is an elongate-oval shape, yellowish-white, and about one-twenty-fifth inch long (Fig. 353d). Immediately the female moves an inch or two higher and girdles the stalk by numerous thrusts of her ovipositor, which is thrust in and then given a twist to one side so that it comes out at one side of where it was forced in, and makes a hori- zontal cut. The eggs are laid in late May and early June and hatch in about eleven days. The young larvge bore into the pith, but the tunnel rarely extends over six inches below the point girdled. The full- Fig. 354.— Currant stem girdled by the grown larva is hardly one- stem-girdler. (After Slingerland.) half inch long, of a ghstening straw-yellow color, with darker head. The thoracic segments are wider than the others and bear rudimen- tary feet, and from the tip of the stout, cylindrical abdomen projects a horny, brown bifid spine. In the fall the borer cleans out its burrow at the lower end and eats a hole through the woody wall of the stem to the outer bark, which sinks in at this point. The grub then spins a thin silken cocoon about itself, in which it hibernates over winter, transforming to a whitish pupa in April, from which the adult emerges early in May. The girdling of the stalks is the principal injury, and those which harbor the pest may be recognized, even in winter, by the characteristic dead stubs, cut off squarely at the upper end. 422 INSECT PESTS OF FARM, GARDEN AND ORCHARD Control. — The drooping of the tips in May is soon noticed and during June they should be cut off about three inches lower down and burned, or if the pruning is left until winter the infested stubs should be cut off about eight inches below the point girdled, as the larvae rarely tunnel deeper. The Four-lined Leaf -bug * This is one of our most common leaf-bugs, which has a long list of food plants, but is particularly injurious to the young fohage of currant and gooseberry. The adult bug is easily recognized, as the upper surface is a dark green with four stripes and the tips of the wing-covers black, as shown Fig. 355. — The four-lined leai-hug (PcBcilocapsiis lineatus Fab.): a, adult; 6, cross-section of stem showing eggs in position and a single egg greatly enlarged. (After Slingerland.) in Fig. 355. The green changes to yellow after death and the body is bright orange-yellow, and the legs green. The "presence of the pest is indicated by the appearance of the pecuKar brown depressed spots on the tender terminal leaves" in early summer. "As the attack continues, whole leaves turn brown, curl up, become brittle, and are torn or broken by the wind. The young shoot is checked and frequently droops and dies. The buds of dahlias and roses are often blasted." Slingerland gives a list of some fifty-seven food- plants, including all sorts of crops, ornamental plants and weeds. * Pcecilocapsus lineatus Fab. Family Capsidoe. etin 58, Cornell Univ. Agr. Exp. Sta. See Slingerland, Bui- INSECTS INJURIOUS TO CURRANT AND GOOSEBERRY 423 Parsnip, mint, sage, rose, deutzia, dahlia, and others are often badly injured. The species has been observed from Canada to Georgia and westward to the Dakotas, so that it is probably generally distributed east of the Rockies. Life History. — The nymphs hatch from the overwintering eggs in late May and early June and are very largely responsible for the injury to the foliage. The newly hatched nymph is only about one-twentieth inch long, but is easily recognized by the shin- ing vermilion-red color of the body, marked with large blackish spots on the thorax and with greenish-black antennse and legs. The nymphs grow rapidly, becoming full grown in seventeen to twenty days after hatching, during which time they have molted five times. The full-grown nymph is about one-fifth inch long, bright orange yellow, and the black wing-pads extend half way to the end of the Fig. 356. — Currant leaf spotted by the nymphs of the four-hned leaf-bug. (After Slingerland.) abdomen and bear a yellowish green stripe near the outer margin. The nymphs feed on the tenderest young leaves, sucking out the juices and soft tissue through their tiny beaks, and thus causing the spots mentioned. "As the nymphs increase in size the spots are a Kttle larger and more numerous, until not only hundreds occur on a single leaf, but often nearly all the parenchyma is taken from the leaf." The nymphs are very active and dart from one side of the leaf to the other when disturbed. The adult bugs appear about the middle of June and are active for a month or more, when they disappear. They mate and the females commence to lay 424 INSECT PESTS OF FARM, GARDEN AND ORCHARD eggs about a week after they first appear. The female is furnished with a strong ovipositor with which she inserts the eggs in slits cut lengthwise into the stems of the plants extending nearly half way through the pith. A half-dozen or more eggs are packed together in the small slit, which may be one-eighth inch long. The indi- vidual egg is about one-sixteenth inch long, light yellow, and shaped as in Fig. 355e, with the upper third capped by a white, finely striated portion. ''With the growth of the surrounding tissue of the stem, the eggs are usually forced out of the slit somewhat, so that about one-half ... of the white portion of the egg pro- jects from the sht." Most of the slits are made two or three inches, rarely over six inches, below the tender tips. Control. — Experiments indicate that the nymphs may be Fig. 357. — Currant leaves killed by the four-lined leaf-bug. (After Slinger- land.) killed by spraying them with kerosene emulsion containing 10 per cent kerosene. Tobacco extracts should also be tried. The adults are not susceptible to this treatment, however. Both nymphs and adults will drop from the foliage when disturbed, and Professor Slingerland has suggested that they might be jarred into a pan of kerosene. By drawing pans, such as constructed for combating the pea-aphis, between the rows and jarring the bugs into them, many might be destroyed. As the eggs are readily recognized, the tips containing them should be cut off and destroyed during the winter. INSECTS INJURIOUS TO CURRANT AND GOOSEBERRY 425 The Currant-aphis * The young foliage of currants, and sometimes of gooseberries, is often found curled up in late spring with many bladder-like galls on the leaves, inside of which are found the numerous yellowish-green plant-lice which have caused them. The wing- less females are about one-twelfth inch long, yellowish-green or green, mottled with darker shades, and with bright red eyes. The winged female is slightly longer, with wings expanding one- third inch. It is bright greenish-yellow, with pale olive head, thoracic lobes brown, and the abdomen is marked by several dark Fig. 358. — Currant foliage curled by aphids. (After Lowe.) transverse bands and lateral spots. It is an old European species and is probably found throughout the United States where currants are grown. Life History. — The life history is practically the same as that of several other aphids previously described and need not be rehearsed m detail. The small black eggs are found on the stalks in winter and hatch just as the foliage appears. The aphids multiply on the fohage, causing it to curl as described, until midsummer, when they either migrate to some other food-plant or become greatly reduced m numbers through the attacks of parasites and predaceous insects, which are very effective in the * Myzus ribis Linn. P'amily ApUdidce. See V. H. Lowe, Bulletin 139, N. Y. Agr Exp. Sta , p. 660, Another species, Rhopalosiphum ribis Linn., is also common on currant and is described and figured by Mr. Lowe. 426 INSECT PESTS OF FARM, GARDEN AND ORCHARD control of this species. Mr. Lowe states that a few females may be found on the foliage throughout the summer. In late October winged males appear and mate with the true females, which then lay the eggs. Control. — The aphids may be readily killed by spraying with kerosene emulsion, whale-oil soap, 1 pound to 6 gallons of water, or tobacco extracts, but the spraying must be done before the Pig. 359. — ^The imported currant-worm (Pteronus ribesii Scop.): a, male and female saw-flies; b, larvs; c, pupa; d, cocoon; e, eggs — all enlarged. (After Lugger.) foliage becomes badly curled. Ordinarily they may be held in check by picking off the curled leaves by hand. The Imported Currant-worm * " The most destructive insect that attacks the currant," says Professor Lugger, " is the above-named saw-fly, which feeds * Pteronus ribeeii Scpp. Family TenthredinidcB. See Lugger, Bulletin 43 Minn. Exp. Agr. Sta., 179; C. L Marlatt, Bulletin 3, T ch. Series, Div Ent., p. 61. INSECTS INJURIOUS TO CURRANT AND GOOSEBERRY 427 indiscriminately on all kinds of currants and gooseberries. The imported species is supposed to have been accidentally introduced into this country about the year 1857, and has since spread over the greater part of the United States and Canada. The eggs are glued to the main-ribs of the leaf as shown in Fig 359, and not inserted into pockets, as is usually the case with saw-flies. . . . In from four to ten days the egg hatches into a very small whitish caterpillar with a white head and ornamented with black spots on each side. This color, however, changes to green as soon as the caterpillars begin to feed, and after their first skin is shed, the head becomes black and many black spots appear on the body. This coloration persists until the last molt when the insect becomes grass-green. The head, however, retains the black spots on each side. The length of the worm is now about three-fourths of an inch. While growing they at first skeletonize the leaves; later they eat the entire leaf, with the exception of the ribs, and at last they devour immense quantities of them, often completely stripping the bushes of their foliage. If this is repeated year after year, the plants produce less and less fruit and eventually die. The larvae now descend to the ground, in which they spin a small, oval cocoon of brownish silk, either just below the surface of the ground or among the leaves and rubbish that collect below the plants. Inside these cocoons they change to pupae and later to adults, which are ready to issue as winged saw-flies during the last of June or in July (in Minnesota), sometimes not until the first of August. They now pair and produce a new generation of injurious worms. . ., the adults of which do not, however, issue until the following spring. As the two broods overlap, we can find larvae of all stages during the greater part of the summer." The adult saw-flies are well illustrated in Fig. 359. The female is about one-third inch long, of a light yellowish color marked with blackish as shown in the figure, while the male is smaller and rather darker. Control. — See next insect. The Native Currant-worm * The native currant-worm is not usually so destructive as the European species, but occasionally, becomes injurious and is * Gymnonychus appendiculatus Hartig. Family Tenthredinidoe. 428 INSECT PESTS OF FARM, GARDEN AND ORCHARD widely distributed, occurring from New England to Minnesota and Colorado, in British Columbia, and probably in the Pacific States. The larva is about two-thirds the size of the imported species, but is uniformly pale-green except the head which is black until the last molt, after which it becomes partly green. One generation of larvae appears in late June and another in August. The cocoons are usually attached to the twigs or leaves of the bushes. The female saw-fly is dull black with dull yellow head, and honey-yellow legs. Control. — While fruiting the foliage should be dusted or sprayed with hellebore, which is the time-honored remedy for currant- worms. However, before the fruit has set and after it is picked, spraying with arsenicals will be much cheaper and more effective, and as it is often desirable to spray gooseberries for diseases with Bordeaux mixture, by adding arsenate of lead or Paris green to it, the worms may be easily controlled. The Currant Span-worm * The Currant Span-worm is readily distinguished from the other currant "worms," by being one of the measuring-worms or inch-worms which loop along as shown in Fig. 360. It is not frequently very destructive, but occasionally becomes a pest, more particularly of black currants and gooseberries, throughout the eastern half of the country. The caterpillar is slightly over an inch long when full grown, and of a whitish color with a wide yellow stripe down the back, another along each side, and several black spots on each segment. The under side is white with a slight pinkish tinge, with a broad yellow median stripe, and is also spotted with black. The moth has a wing expanse of about \\ inches, is a pale yellowish color, with several brownish spots, varying in size and sometimes forming one or two irregular bands across the wings. Life History. — The eggs (Fig. 360a) are laid in midsummer on the twigs of the infested plants and hatch as the bushes come into full leaf the next spring. The caterpillars become full grown in three or four weeks, when they pupate just beneath the surface of the soil, and two or three weeks later the moths emerge. * Cymatophora ribearia Fitch. Family Geometridce. INSECTS INJURIOUS TO'CURRANT AND GOOSEBERRY 429 Control. — Hellebore is not as effective as against the saw-fly larvae and as the larvae usually appear before the fruit is setting, they may be better controlled by spraying with arsenicals. When the caterpillars are disturbed they drop from the foliage, letting themselves down by a silken thread and remaining suspended in Fig. 360. — -The currant span-worm {Cymatomorpha riberia Fitch): 1, 2, larvae; 3, pupa; a, egg; b, eggs on twig; c, moth — a, much enlarged, others natural size. (After Saunders.) mid-air until danger is over, when they reascend the thread. This habit may be utiKzed for their destruction by jarring the bush so that they will drop, and then passing a forked stick around it so that all the threads may be caught and the caterpillars may be drawn out in groups and crushed with the foot. The Currant-fly * Currants and gooseberries sometimes turn red and drop pre- maturely, due to the injury by small maggots which may be found within them. The insect has been troublesome in Maine and is sometimes a serious pest in Colorado. It is a native insect and is probably generally distributed throughout the northern United States and southern Canada. The adult fly is about the size of * Epochra canadensis Loew. Family Trypetidce. See F. L. Harvey, Bulletin 35, Maine Agr. Exp. Sta. 430 INSECT PESTS OF FARM, GARDEN AND ORCHARD a house-fly, a pale yellowish or yellowish-brown color, with dark bands across the wings, and a tapering abdomen, as shown in Fig. 361. Life History. — The flies appear in late spring and the females deposit their eggs in the older berries. A female will lay about 200 eggs during the period of a month, placing but one in a berry, so that a single fly may do considerable damage. The white egg is about one-twentj^-fifth inch long and laid just under the skin, where it is easily seen. The egg hatches in a few days into a Fig. 361.— The currant-fly (Epochra canadensis Loew.)— much enlarged; (After Gillette.) small white maggot, which burrows around the berry and then feeds upon the seeds. The location of the larva may be seen, as the infested currant soon shows a clouded appearance and finally turns red and a black spot appears. The maggot becomes full grown in about three weeks and then eats its way out of the berry, which has usually fallen to the ground. The mature maggot enters the soil for about an inch and there changes to the pupa, from which the fly emerges the next spring. Control— As the maggots usually remain in the berries a few days after they drop, all fallen berries should be frequently INSECTS INJURIOUS TO CURRANT AND GOOSEBERRY 431 picked up and destroyed. Poultry running among the bushes will do this very effectually. Other methods will suggest them- selves from the above life history, but none seems to have been carefully tested. CHAPTER XXIII INSECTS INJURIOUS TO THE GRAPE. * The Grapevine Phylloxera f This insect is native east of the Rocky Mountains, where it has always lived upon wild vines and did not attract attention until it was imported into France about 1859, as it does prac- tically no damage to the native American grapes. It soon spread through the principal wine districts of southern Europe, where it caused immense losses and the temporary abandon- ment of vineyards, due to the fact that the European varieties are very suscep- tible and readily succumb to injury by it. It has spread to southern Russia and the adjoining count- ries of Asia, and Algeria, and has been carried to New Zealand and South Africa. In this country it is injurious only in Cal- ifornia, where it was imported on French vines about 1874. It was first noticed in Sonoma County and since then has spread to all the principal grape-growing regions north of Tehachapi and has probably destroyed 50,000 acres. This aphid exists in several forms, which injure both foliage and roots. On the leaves irregular spherical galls are produced, and the root-inhabiting form produces galls on the roots. The * See A. L. Quaintance, Farmers' Bulletin 284, U. S. Dept. Agr. H J. Quayle, Bulletin 192, Cal. Agr. Exp. Sta.; F. Z. Hartzell, Bulletin 331, N. Y. Agr. Exp. Sta. t Phylloxera vastatrix Planchon. Family Aphididoe. See C. L. Marlatt, Farmers' Bulletin 70, U. S. Dept. Agr., and Quayle, 1. c. 432 Fig. 362. — The grapevine phylloxera (Phyl- loxera vastatrix Flanchon) : a, true sexual female, the dark colored area indicating the sinp:le egg; b, egg; c, shrivelled female after oviposition ; d, foot of same ; e, rud- imentary and functionless mouth-parts. (After Marlatt, U. S. Dept. Agr.) INSECTS INJURIOUS TO THE GRAPE 433 leaf-galls are very common on American grapes, but are no indication of the pi'esence of the root form, as the roots are rarely injured where the foliage is covered with leaf-galls. On the other hand the European varieties rarely exhibit any leaf -galls, but are very susceptible to the root phylloxera, which multiplies without any external indication of its presence until the vine is seriously injured. The injury to the vine is not due so much to the sap taken from the vine by the myriads of aphids which may inhal^it the roots, as to their poisonous effect on the root tissue and its subsequent decay. Wherever the phylloxera attack the roots, small swelUngs are pro- duced, composed of soft tissue which soon decays. When such a gall is formed at the end of a young root, its growth is stopped, and on larger roots a decay sets in which finally girdles the root and all below the injured point dies. As all the roots become affected the vine stops growing, the leaves be- come sickly and yellow- Fig. 363.— Under side of grape leaf showing ish, and the vine dies, and ^^^^ ^^used by Phylloxera. (After RHey.) the phylloxera disappears from the rotting roots, so that the cause of the injury would be obscure were the nature of the injury not known. Life History. — The life history of the phylloxera is a com- phcated one, involving four different forms of aphids; the leaf- gall form, the root or destructive form, the winged or colonizing form, and the sexual form. The winter eggs are deposited on the rough bark of the old wood in the fall and hatch the following spring. The young aphids settle on the leaves, where the irrita- tion caused by their mouth-parts soon causes a depression around each which forms a gall projecting on the lower side of the leaf. "In about fifteen days the louse becomes a plump orange-yellow, full-grown, wingless female, and fills its gall with small yellow 434 INSECT PESTS OF FARM, GARDEN AND ORCHARD eggs, dying soon after. The eggs hatch in about eight days into young females again, hke the parent, and migrate to all parts of the vine to form new galls. Six or seven generations of these wingless females follow one another throughout the summer, frequently completely studding the leaves with galls." In Cali- fornia the young hatching from the winter eggs go directly to the roots where they give rise to new colonies, there being no gall forms, according to Quayle. Where the leaf-gall females Fig. 364. — The grapevine phylloxera: a, winged migrating female; b, last stage of nymph of same; c, mouth-parts with thread-like sucking setae removed from sheath; d, and e, eggs of male and female, showing sculp- turing — all enlarged. (After Marlatt, U. S. Dept. Agr.) occur many of them probably migrate to the roots during the summer, and all do so with the approach of cold weather. In the spring the roots are attacked and a series of generations of wingless females multiply on them. As there are five to seven generations in a season and each female lays from 30 (Quayle) to 100 (Marlatt) eggs, it is evident that they will soon be numerous enough to destroy the vine. The root-inhabiting females are very similar to those in the leaf -galls, and are about one-twenty-fifth inch long when mature and half as long when young and active. They are light greenish-yellow in summer and darker in winter, and when numerous the infested roots look as if dusted in spots with pow- INSECTS INJURIOUS TO THE GRAPE 435 dered mustard, according to Quayle. He states that "the newly- hatched insect is fairly active, and at first moves from place to place on the roots, but finally, when it reaches the egg-laying stage, inserts its sucking-tube into the root and remains fixed." During the late summer and early fall some of the root-lice develop into winged females which escape through cracks in the soil and fly to neighboring vines. They lay from two to four eggs beneath the loose bark on the old wood and soon die. "The eggs are of two sizes, the smaller and fewer in number yielding males in nine or ten days, and the larger the females of the only sexed genera- tion in the whole life round of the insect. In this last and sexed stage the mouth-parts of both sexes are rudi- mentary, and no food at all is taken. The insect is very minute and resembles the newly hatched louse of either the gall or root form. After fertili- zation the single egg of the larva-Hke female rapidly increases in size until it fills the entire body of the mother and is laid within three or four days, bringing us back to the starting point." * The phylloxera has been distributed over the world by infested rooted plants or cuttings bearing winter eggs, and it spreads locally by means of the winged females, by the escape of the young root-lice through ci-acks of the soil and their migration to neighboring plants, or by bits of infested roots being spread in cultivation, and by the leaf-gall lice being spread to other plants by the wind or by being carried by birds or insects. Control. — The principal means of control lies in the use of resistant vines. These may be varieties which have proven successful in the eastern United States, where the insect is native, or more commonly the stocks of grapes from the Eastern States * Quotations from Marlatt, 1. c. Fig. 365. — Grapevine phylloxera: a, root galls; b, enlargement of same showing disposition of lice; c, root-gall louse — much enlarged. (Mter Marlatt, U- S. Dept. Agr.) 436 INSECT PESTS OF FARM, GARDEN AND ORCHARD are grafted with the desired varieties. There is a marked varia- tion in the resistance of different species and varieties and not all of them can be successfully used as stocks for the desired scions, so that the successful use of the method, which is fully outUned by Quayle, I.e., requires a considerable knowledge of viticulture. Carbon bisulfide has been used very extensively for destroying the root-hce, but is expensive and is only appHcable on rich, deep, loose, soils. It cannot be used successfully on soils containing much clay, or on dry rocky hillsides, or when the soil is saturated with moisture, and is most effective on sandy soils where the insect is least injurious. It is now seldom used and is considered impractical by growers. One of the best methods of destroying the root-lice where water is available is by submersion. In California the best results are secured by flooding with at least six inches of water for a week or ten days as soon as the vines have ceased active growth in November. A little later two to three weeks' submersion will be necessary and in winter thirty-five to forty days. Flooding for a couple of days in midsummer seems to destroy some of the insects, but its main value is in stimulating a vigorous growth of new rootlets. Longer flooding in summer, when the aphids might be most easily destroyed, injures the vines. On very sandy soils vines are uninjured by the phylloxera. All sandy soils are unfavorable to the pest and vines on them die more slowly, but to secure complete immunity there must be at least 60 per cent of silicious sand. Sands containing clay or which form lumps offer less resistance. The Grapevine Root-borer * The larvae of the Grapevine Root-borer feed in the old roots at some Httle distance from the base of the vine, and as there are no indications of the pest, its presence may easily pass unnoticed. Although not generally recognized as a serious one it has been known as a pest of the grape for fifty years, and has been observed to do considerable damage in Kentucky and West Virginia. Although the vines are not killed, they are so enfeebled that they make but little growth and the crop is much curtailed. All * Memythrus polistiformis Harris. Family Sesiidce. See Fred E. Brooks, Bulletin 110, W. Va. Agr. Exp. Sta., and Bulletin 730, U. S. Dept. Agr. INSECTS INJURIOUS TO THE GRAPE 437 varieties are affected in West Virginia, including the wild fox grape, Vitis labrusca. It is stated that in the South the Scupper- nong, or southern wild fox grape, is immune from attack. The species has been observed from Minnesota and Kansas eastward through Ohio and Kentucky to West Virginia and North Carohna. The parents of the borers are clear-winged moths nearly Fig. 366. — The grapevine root-borer (Memythrus polistiformis Harris) : male and female moths on wild lettuce leaf under grapevine — natural size. (From Brooks.) related to the peach-tree borer, currant-borer, and raspberry- borer. The females are seven-eighths inch long with wings expand- ing 1^ inches. They are a dark lustrous brown color, the fore- wings being brown and the hind-wings transparent and bordered with brown. The posterior margins of the second and fourth abdominal segments are orange or lemon-yellow, and there are spots of the same color at the bases of the wings. The males 438 INSECT PESTS OF FARM, GARDEN AND ORCHARD are considerably smaller than the females. The moths fly during the day and are readily mistaken for wasps of the genus Polistes. The males fly in a quick, wasp-like manner, and when they rest on a leaf will occasionally flutter the wings hke an angry wasp, which is accompanied by a low buzzing sound, which makes the mimicry very effective. t Life History. — The eggs are laid singly on weeds, grasses or other vegetation in the vineyard or on the bark or leaves of the , „...,.-,,, ^ — : — ^. , vines, a single female laying some 400 eggs. • The egg is oval, one-twenty-fifth inch long, J of chocolate-brown color, and finely pitted ' and sculptured. They are very readily washed off by the rain and drop to the soil, where they hatch in about three weeks. The Httle - larvae bore directly into the soil, wherever Fig. 367. — Egg of ^^ey may be, in search of grape roots, and grapevine root- • r- i i •,^ , borer v e r y may survive for several days without any greatly enlarged, food. Upon reaching a root the larva bores through the outer bark and then makes an irregular burrow in the softer parts of the bark, which may encircle the root several times. As the burrows grow larger they run with the grain of the wood, and as they are enlarg- ed with the growth of the larva, only the outer bark is left on roots one-half inch or less in diameter, the interior being tunnelled out and filled with the castings of the larva. Most of the larvae feed a foot or so from the base of the vine, though one was found on a root nine feet from the base. The larvse bore in the roots until the second fall, when they are about full grown and make cells or hibernacula, thinly fined with silk, in which they hibernate in the root. The larva becomes full grown the next spring and is then 1| to If inches long, of the general shape shown in Fig. 368, yellowish-white, with a small brown head, three pairs of brown thoracic legs, and five pairs of abdominal prolegs. When ready to pupate the larva comes near the surface of the soil and there makes a tough cocoon an inch or so long, composed of earth and excrement and fined with silk, and in it transforms to a brown pupa with yellow bands around the abdomen. In about four or five weeks the pupa wriggles half way out of the cocoon and the moth emerges, leaving the empty pupal skin INSECTS INJURIOUS TO THE GRAPE 439 projecting above the surface of the ground. The moths emerge in late July and early August in West Virginia and the eggs are laid in a few days. Thus the life cycle requires two full years and larvae of two sizes may be found in the roots at any time, except during the pupal period, when all will be about half to two-thirds grown. Control. — On ac- count of their sub- terranean habits it is manifestly im- possible to dig out the borers, as is done with similar species except for a few valuable vines. If the Scuppernong is as immune as has been reported, it might be used as a stock throughout the South, where it will thrive. By recognizing the par- ent moths, they may be destroyed by approaching them quietly when at rest and striking them quickly with a paddle or board and many might thus be killed during the time they arc most abundant. By thorough cultivation in June and July many of the cocoons will be thrown to the surface or buried so deeply that many of the pupse will be destroyed, or the adults will be unable to reach the surface. With liberal fertilization, cultivation will stimu- late the vine to withstand the injury. Brooks has shown that in West Virginia the crested flycatcher (Myiarchus crinitus) Fkt. o'lS. — Grapevine root-borers at, work. Five Itoieis were feeding in this section when taken from size. (Photo by the grountl — two-thirds natural W. E. Runisey.) Fig. 369. — Grape root-worm (Fidia viticida Walsh): beetles feeding on foliage — natural size, and enlarged. (After Slingerland.) 440 INSECTS INJURIOUS TO THE GRAPE 441 feeds upon the moths and may be a factor in the control of the pest The Grape Root-worm * The Grape Root-worm is the larva of a small, hairy, chestnut- brown beetle which feeds on the upper surfaces of the leaves Fig. 370. — ^The life cycle of the grape root-worm— enlarged and natural size. (After Slingerland.) eating out series of patches or holes in characteristic chain-like feeding marks which afford an easily recognizable indication of the * Fidia viticida Walsh. Family Chrysomelidce. See Quaintance, I.e.; Hartzell, I.e., and Bulletin 453, N. Y. Agr. Exp. Sta.; M. V. Slingerland, Bulletins 184, 208, 224, and 235, Cornell Univ. Agr. Exp. Sta.; E. P. Felt, Bulletin 19, Office State Ent. of N. Y.; Fred Johnson, Bulletin 68, Part VI, Bureau Entomology, U. S. Dept. Agr.; Johnson and Hammar, Bulletin 89, ibid. 442 INSECT PESTS OF FARM, GARDEN AND ORCHARD presence of the pest in the vineyard. The larvae devour the smaller roots and eat out pits and burrows in the larger roots, and where abundant may kill the plants in a year or two, but more commonly they cause an enfeebled growth and a consequent failure to produce profitable crops. Injury has been most severe in the grape belt of western New York, Pennsylvania, and northern Ohio, but the species occurs generally throughout the Mississippi Valley and Fig. 371. — Eggs of ttie grape root-worm, natural size as seen on grape canes above — enlarged below. (After Slingerland.) the Eastern States, and has been reported from California. "The insect thrives best in vineyards which are neglected, and in the absence of cultivation and timely spraying it is likely to become a serious pest in any vineyard throughout its range of d^lstribu- tion. This is especially the case in light, sandy soils and in regions where grape growing is a considerable industry." A nearly related species,* has been known to injure the foliage seriously * Fidia cana. INSECTS INJURIOUS TO THE GRAPE 443 in Texas, but it is not known whether it affects the roots. In Cahfornia, the imported grape root-worm * is sometimes destruc- tive, has practically identical habits, and is controlled by the same methods. The adult beetle is about one-quarter inch long, brownish in color, and covered with grayish-white hairs, with a stout body and long legs, as .shown in Fig. 369. The full-grown larva is about five-eighths inch long, whitish in color, and usually rests in a curved position as shown in Fig. 370. The head is shghtly Fig. 372. — Portions of three grape root.s denuded of their bark and fibrous roots by grape root-worms, and part of a similar root taken from a thrifty vine, showing its normal bark and rootlets. Reduced in size. (After Slingerland.) narrower than the body and yellowish-brown, as are the well- marked spiracles on the side of each segment. Life History. — The adult beetles appear about the close of the blooming period, or in late June and early July in the latitude of New York, and live for a month or more. They emerge earher on warm, light sandy soils, and later on heavier soils. In a few * Adoxus viiis Fourcroy. A small, shining, brown or black beetle, one- fifth inch long. See Quayle, I.e. 444 INSECT PESTS OF FARM, GARDEN AND ORCHARD days their feeding commences to be noticed on the leaves and the females may be found laying their eggs. A female will lay from 150 to 900 eggs, averaging about 175, most of which are laid during the first two or three weeks. The eggs are laid in masses of 25 to 40 beneath the old bark or generally over the canes. The individual egg is one-twenty-fifth inch long, at first whitish, but soon turns yellow, and tapers at each end. The eggs hatch in from nine to twelve days, when the young larvae drop to the ground and seek the roots. The young larvse are only one- seventeenth inch long, so that they are able to penetrate the soil. When established on the roots they feed freely and grow rapidly, Fig. 373. — I'he tender pupa of the grape root-worm in its earthen cell, enlarged — natural size at n. (After Slingerland.) becoming nearly full grown by fall. In the fall they descend several inches into the soil and make small earthen cells, in which they hibernate. In the spring they return to the roots nearer the surface, and those not already full grown feed until growth is completed. They then make small earthen cells 2 or 3 inches below the surface of the ground in which they transform to pupae. These cells are easily broken open and the pupse are thus crushed or killed by stirring the soil in cultivation. The pupa, shown in Fig. 373e, is one-quarter to one-third inch long, whitish, with the head, thorax and tip of the abdomen pinkish, and with spines on the head, appendages, and abdomen as illustrated. The pupse are most abundant in New York during June, the pupal stage lasting about two weeks. INSECTS INJURIOUS TO THE GRAPE 445 Control. — Extensive experiments made by several investigators have shown that the beetles may be very largely destroyed by thorough spraying with arsenate of lead just as they appear. By applying the poison when they are first noticed feeding they may be killed off before many of the eggs are laid, and sprayed vineyards have shown a reduction of over 90 per cent of the eggs found on untreated vines. Arsenate of lead should be appHed at the rate of 3 pounds to the barrel as soon as feeding marks are found on the foliage, and again a week or ten days later, and should be added to the Bordeaux mixture used for the diseases of the vine. The spraying must be done with the greatest thor- oughness, as the beetles dislike the sprayed foHage and will seek out that which has been missed. The nozzles on trac- tion outfits should therefore be arranged so as to hit all parts of the vines (see Fig. 374) and the pump should maintain at least 100 pounds pressure. With the machines in common use not over 7 or 8 acres a day may be covered thoroughly, and about 125 gallons will be required per acre. If the work is hurried to cover greater acreage, the treatment will usually be less effec- tive. When the infestation is unusually severe cheap molasses may be added to the arsenate spray to make it attractive to the beetles. The beetle is noticeably less destructive in well-cultivated vineyards, and it has been shown that thorough cultivation in early summer breaks up the pupal cells and destroys large num- bers of the pupae. Most of the pupse are within 2 or 3 inches of the surface and within 1| or 2 feet from the base of the vine. In the fall the earth should be thrown toward the vines to form a ridge along the row, so that the larvae will mostly pupate near the surface of this ridge. The next spring, when most of the larvae have entered the pupal stage, this ridge should be thrown away from the vines, thus exposing the pupae. A "horse-hoe" Fig. 374. — A power sprayer with noz- zles arranged for grape spraying (The Bean Spray Pump Co.) 446 INSECT PESTS OF FARM, GARDEN AND ORCHARD commonly used in vineyards is useful in this work, but a hand- hoe will need to be used to throw the earth away from the imme- diate base of the vine. The soil should then be kept well stirred by cultivation at frequent intervals, all of which is merely part of good practice, independent of the control of the root-worm. The Grapecane Gall-maker * The Grapecane Gall-maker is a small reddish-brown snout- beetle about one-eighth inch long, which lays its eggs in the canes, giving rise to galls about twice the diameter of the cane and 1 or 1| inches long, with a deep scar in one side. It has been noted as injurious in Ohio and West Virginia, and fromtherecords seems to be gen- erally distrib- uted over the Eastern States, but is by no means a serious pest. Life History. — The adult beetles appear in May and are gone by early July. They feed sparingly on the vine, making httle pits in the tendrils, in the buds or bark of new canes or in the midribs on the under side of the leaves. The females soon lay their eggs and make the egg scars. These cause the galls Fig. 375. — The grapecane gall-maker (Ampeloglypter sesostris Lee.) : a, adult from above; b, same, side view; c, larva, side view; d, pupa; e, section of vine showing galls — all enlarged. (After F. M. Webster.) Natural size. (After Brooks.) * Ampeloglypter sesostris Lee. Family CurcuUonidce. See Fred E. Brooks, Bulletin 119, W. Va. Agr. Exp. Sta..; F. M Webster, Bulletin 116, Ohio Agr. Exp. Sta. ie INSECTS INJURIOUS TO THE GRAPE 447 and constitute practically the only injury to the vine. The eggs are laid just above a joint and beyond the outermost fruit, so that the injury does not interfere with the crop. A female eats out a small hole with her snout, in it lays a small yellowish-white egg, and fills up the hole with fibers scraped off from the surface of the cane. She then makes another hole immediately above this, but merely places a drop of hquid in it and then fills it up with fibers in the same manner. Eight to a dozen holes are thus made in a row and filled. Very soon this wound causes a swelKng of the vine, but the gall does not reach full size for six or eight weeks. On vines producing dark-colored fruit, the wood about the wound takes on a purplish color. The galls seem to have but Httle effect on the growth and vigor of the vine, except that the canes are more readily broken by the wind or in pruning. The larva is a little yellowish-white, footless grub about two-fifths inch long, which feeds about the egg-chamber and then burrows in the pith. It becomes full grown in eight to ten weeks, when it pupates within the burrow; the beetle emerges in late August, and hibernates over winter. As the scar in the side of the gall where the eggs were deposited remains open, a very large proportion of the larvae are subse- quently parasitized by various chalcis, and tachina-flies, which will probably prevent the insect ever becoming much of a pest. Control. — The galls may be cut out and burned during July or August without any injury to the crop, as they occur beyond the fruit, and at that time will contain the larvse or pupae. As the beetles feed on the foliage and new growth it is probable that but little damage will result in vineyards well sprayed with arsenicals for other pests. The Grapecane Girdler * This beetle is very similar to the last except that it is black in color. Its native food-plant is the Virginia creeper, which it has deserted in West Virginia, and occasionally elsewhere, to attack grape. The species seems to occur generally through the Central and Eastern States. * Ampeloglypter ater Lee. Family Curculionidce. See Fred E. Brooks, Bulletin 119, W. Va. Agr. Exp. Sta. 448 INSECT PESTS OF FARM, GARDEN AND ORCHARD Life History. — The life history is almost identical with that of the preceding species, the habit of the species differing only in the manner of oviposition. The eggs are laid in late May and early June. In laying the egg, the female deposits it in the same manner as does the previous species, and then instead of placing a series of holes in a row she makes them in a ring around the cane, only the first one containing an egg. She then goes to the next joint above and makes a series of holes around it, com- pletely severing it, so that it hangs by a shred and soon drops. The httle larva feeds in the pith of the joints on either side of the egg puncture, and these two joints die and drop to the ground. The larva becomes full grown in about a month and changes to Fig. 376. — The grapecane girdler (Ampeloglypter ater Lee): a, egg; b, larva; c, pupa; d, beetle — all enlarged. (After Brooks.) a pupa in its burrows soon after the dead section drops, first filKng the burrow with little pellets of fibres. Two weeks later the adult beetle emerges, appearing during late summer. The whole life cycle thus requires sixty-five to seventy days. The beetles hibernate over winter. Control. — The injured canes are quite conspicuous in early summer and by cutting them off a few inches below the egg scars the eggs and larvae may be removed and destroyed. Brooks is of the opinion that the beetles will be largely destroyed in vine- yards thoroughly sprayed with arsenicals for other grape insects. INSECTS INJURIOUS TO THE GRAPE 449 The Grape Cane-borer * During the spring young grape shoots sometimes suddenly break off or droop and die, and if examined a small hole will be found just above the base of the withered shoot, with a burrow leading from it into the main stem. In this bur- row will be found a small brown beetle, a half inch long (Fig. 378a), which is the cause of the injury. It has been sometimes called the apple twig-borer on account of the similar injury which it does to apple twigs, and it also attacks pear, peach, plum, forest and shade trees and ornamental shrubs, but it is Fig. 377. — Work of the grapecane girdler. (After Brooks.) * Amphiceriis bicaudatus Say. Family Ptinidce. See C. L. Marlatt, Farmers' Bulletin 70, U. S. Dept. Agr. 450 INSECT PESTS OF FARM, GARDEN AND ORCHARD particularly destructive to the grape. Its injury is most noticed in winter and early spring, and frequently results in killing all the new growth and sometimes the entire vine. Injury has been most severe in the states bordering the Mississippi from Iowa southward, where it is one of the most serious insect pests of the vine, and though the beetle occurs eastward to the coast it rarely does much damage farther east. Fig. 378. — The grape nane-borer (Amphicerus bicaudatus Say): a, beetle, back and side views; b, pupa; c, larva, with feet enlarged; d, burrow in apple twig made by adult; e, larval gallery in tamarisk, with pupa in cell at end ; /, injury to young shoots and cane showing entrance of beetle near/, and the characteristic wilting and new growth — all much enlarged except d, e, f. (After Marlatt, U. S. Dept. Agr.) "It breeds in dying wood, such as large prunings, diseased canes, and also in dying or drying wood of most shade and fruit trees. It has also been found by the writer [Marlatt] breeding INSECTS INJURIOUS TO THE GRAPE 451 very abundantly in roots of uprooted maples and in diseased tamarisk stems. In old, dry wood it will not breed, so far as known, nor in vigorous live growth, but seems to need the dying and partially drjdng conditions mentioned. The insect has but one brood yearly. The beetles mature for the most part in the fall, and generally remain in their larval burrows until the follow- ing spring. A few may leave the burrows in the fall and con- struct others in the twigs of apple or other plants in which to hibernate. In the spring, however, they begin their destructive work early, burrowing into the axils of the grape and occasionally also into other plants. This is undoubtedly partly for food, but seems largely malicious, for it certainly has nothing to do with egg-laying. . . . The eggs are laid chiefly in May or April in its southern range, and the larvae develop during summer, trans- forming to beetles and pupae in the fall. On the Pacific coast a closely allied, but somewhat larger species {Amphicerus puncti- pennis Lee.) . . . probably has similar . . . habits . . ." Control. — All diseased wood and prunings should be removed in late spring, thus destroying the material in which the larvae develop. If this is neglected and the beetles appear in the vine- yard, the only means of stopping their depredations is to cut out by hand the affected parts and destroy the beetles. On warm days the beetles may sometimes be collected while running over the vines. The Grapevine Flea-beetle * When the grape buds are swollen in the spring they are often attacked by numbers of little blue or greenish beetles which eat out or entirely consume them. When abundant these little beetles may destroy all the buds on a vine, thus greatly retarding the leafing out or even occasionally killing the plant. The beetle is about one-fifth inch long, of robust shape, and possesses the thick thighs characteristic of flea-beetles, which enable it to jump a considerable distance when disturbed. It is common through- out the States east of the 100th meridian and nearly related species do similar damage on the Pacific Coast. (See Quayle, I.e.) The wild grape is undoubtedly the natural food-plant of * Haltica chalybea 111. Family Chrysomelidce. See Quaintance, I.e.; Hartzell, I.e.; and M. V. Slingerland, Bulletin 157, Cornell Univ. Agr. Exp. Sta. 452 INSECT PESTS OF FARM, GARDEN AND ORCHARD the species, though it is occasionally found on plum, apple, pear, quince, blue beech and elm. Life History. — After feeding a few days the female beetles commence to lay their eggs in cracks of the bark at the base of the buds, or in any crevice or in the cavity eaten out of the bud by the beetle, or sometimes on the foliage. The eggs are a long oval shape, one-fortieth inch long, and of a dark straw-yellow color. The eggs hatch just as the young leaves are expanding. Fig. 379. — The grapevine flea-beetle (Haltica chalyhea 111.): a, adult with hind leg at right further enlarged; b, larva, much enlarged; c, beetles and larvae on foliage — natural size; d, beetle feeding on bud; e, diseased beetles. (After Marlatt, U. S. Dept. Agr.) and upon them the young larvae feed greedily. The larvae feed on the upper surface of the leaf, eating out irregular holes through the skin and into the soft tissue, and become full grown in three or four weeks. The young larvae are a very dark brown, but when grown they are one-third inch long and a dark yellowish- brown, marked by regular rows of blackish tubercles each of which bears a small hair. The head, anal and prothoracic plates and legs are black. The full-grown larva drops to the ground and an inch or two beneath the surface makes a small cell in which INSECTS INJURIOUS TO THE GRAPE 453 it transforms to a -white pupa, from which the adult beetle emerges in one or two weeks. In New York there is but a single generation, but more than one generation may occur in the South. Upon emerging the beetles feed on the grape and other plants, doing no particular damage, and enter hibernation in the fall. Control. — Where vineyards are regularly sprayed with arsen- icals there will be but little trouble with the flea-beetles, as the grubs are very easily destroyed on the foliage. In neglected vineyards the beetles often become very abundant and may be Fig. 380. — ^Eggs of the grapevine flea-beetle, natural size at a, and enlarged at b. (After Slingerlancl.) quite destructive in such localities. Where it is necessary to combat the beetles to prevent injury to the buds, close watch should be kept for them and the buds should be thoroughly sprayed at once, using 4 pounds of arsenate of lead per barrel. Usually this will need to be applied just as the buds are becoming well swollen, and must be applied promptly and thoroughly, as the beetles work quickly and a day's delay may mean the destruction of the buds. In a small vineyard or on a few vines the beetles may be collected by hand in the early morning when they are sluggish, or may be jarred to canvas-covered frames kept saturated with kerosene placed beneath the vines. 454 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Rose-chafer * » About the time the grape is in bloom, immense swarms of the common Rose-chafers or Rose-bugs often appear, covering the plants, feeding on the blossoms, later attacking the young fruit and foliage, and sometimes eating the leaves quite bare except the larger veins. The chief damage, however, is done by destroy- ing the blossoms or newly set fruit, or by so injuring the young berries that they are misshapen and worthless The beetle is Fig. 381. — The rose chafer (Macrodadyhis subspinosus Fab.): a, beetle; b, larva; c, d, mouth-parts of same; e, pupa — all much enlarged; /, beetles at work on foliage — natural size. (After Marlatt, U. S. Dept. Agr.) about one-third inch long, of a light-brownish color, covered with numerous hghter hairs, and has very long spiny legs, which always seem to be in its way and make it most awkward and clumsy. It IS a very general feeder, being common on roses, from which the common name is received, and also on such orna- * Macrodadylus subspinosus Fab. Family Scarabopidoe. See Quaintance, I.e.; Hartzell, I.e.; J. B. Smith, Bulletin 82, N. J. Agr. Exp. Sta.; Fred John- son, Bulletin 97, Part III, Bureau of Entomology, U. S. Dept. Agr.; and F. H Chittenden, Farmers' Bulletin 721, U S. Dept. Agr. INSECTS INJURIOUS TO THE GRAPE 455 mentals as Spiraea and Deutzia, while it frequently injures the blossoms of apple, plums, cherries and peaches, and when very abundant will attack various vegetables, grasses, and grains. The species occurs commonly from Canada to Virginia and Tennes- see and westward to Colorado, and in Texas and Oklahoma, but seems to do but little damage west of the Mississippi, being most injurious in the Middle States. It is particularly destructive where there are areas of light sandy soil grown up in grasses and weeds, upon the roots of which the larvae feed. Life History. — After feeding three or four weeks the beetles suddenly disappear. During the middle of June, in New Jersey, the females lay from 12 to 20 eggs, depositing them in the soil singly. These hatch in two to three weeks and the larvae feed on the roots of various grasses and possibly weeds and other vegetation. They become nearly full grown by fall, when they go below the frost line and hibernate over winter. The larva looks very much like a small white grub, which it closely resembles in every way, and is about three-quarters inch long when full grown (Fig. 381, 6). In the spring the grubs come near the surface of the soil and enter the pupa stage, which lasts from ten to thirty days according to the temperature. There is but one generation a year, and the injury is done by the beetles during the three or four weeks they are abroad. Control. — When the beetles are very abundant the only satis- factory method of control is to pick them by hand or jar them from the vines onto frames from which they may be collected. In jarring, an umbrella-shaped frame covered with canvas or, preferably, oilcloth, which slopes to a can of kerosene at the bottom, is often used, being somewhat similar to that used for the plum curculio. This is held under the vines and they are sharply jarred or shaken, when the beetles will drop to the frame particularly in early morning. Handpicking into a can of kerosene and water is probably the most common method, how- ever. Where the beetles are not excessively abundant they have been controlled in some cases by thorough spraying with arsenate of lead, 5 to 10 pounds per barrel, preferably applied with Bor- deaux mixture, and recent experiments of the N. Y. Agricultural Experiment Station with 5 pounds of arsenate of lead and 12 pounds of glucose per barrel gave excellent results. The num- 456 INSECT PESTS OF FARM, GARDEN AND ORCHARD bers of the pest may also be much reduced by keeping down the grass and weeds in the vineyard, and particularly on hght sandy soils adjoining lands should be broken up and cultivated in annual crops as far as possible, thus reducing the breeding grounds of the pest. By bagging the grapes as soon as the fruit is set the clusters may be protected from this as well as other pests and diseases wherever such treatment is practicable. All recent work seems to indicate that the treatment with arsenate of lead and molasses is the best means of control. The spray should be appHed before the beetles appear in large num- bers and it may be necessary to repeat it once or twice. Self-boiled Hme-sulphur has been said (Headlee) to act as a repellant, but there is need for more experimental work before this can be generally estabUshed. The Grape Leaf-hopper * Wherever the grape is grown in the United States and Canada, the fohage will be found more or less infested with the small Leaf -hoppers, often locally called " thrips," which feed and breed on the under surface of the leaves during the season. By late summer the vines may be covered with the hoppers, which will fly off in clouds when disturbed, and every year there is serious injury in various localities. The injury is done by the httle hoppers sucking out the juices of the leaves through their tube- Uke mouth-parts. A small white spot first appears around the feeding puncture, due to the loss of chlorophyll in the leaf, and when the punctures have become numerous the leaf has a varie- gated appearance. As the injury increases the leaf yellows and finally dries up and falls to the ground. Where it becomes general, this injury reduces both the quantity and quality of the fruit. The pest is an insidious one, as it is not usually noticed until it becomes very abundant in late summer, by which time most of the injury has been done and it is too late to prevent it. For this reason its control has been very generally neglected by grape growers with a consequent loss the cause of which is often unsuspected. * Typhlocyba comes Say. Family Jassidm. See Quaintance, I.e.; Hartzell, I.e., and Bulletin 359, N.'Y. Agr. Expt. Sta.; Quayle, I.e.; and M. V. Slinger- land. Bulletin 215, Cornell Univ. Agr. Exp. Sta., and Fred Johnson, Bulletin 19, U. S. Dept. Agr. INSECTS INJURIOUS TO THE GRAPE 457 The adult hoppers are about one-eighth inch long and the wings are prettily marked with yellow and red as shown in Fig. 382. "In summer the young and adult insects are Ught yellow- ish in color, but before going into hibernation, the eyes of the adults darken and the peculiar yellow spots on the wings change to an orange red, thus giving the hibernating adults a general reddish appearance. These darker markings on the adults vary so much that nine different varieties are now recognized, two of which are represented at b and c, in Fig. 382. Often several Fig. 382. — Grape leaf-hopper (Typhlocyha comes): a, adult female; b, adult male; c, another form of the species, showing variation in markings; d, newly-hatched nymph; e, last stage nymph; /, appearance of injured leaf; g, cast pupa skins — a, e, much enlarged; g, less enlarged;/, reduced. (From Marlatt, U. S. Dept. Agr.) of the varieties may be found together on the same vines, but usually one color form largely predominates." The nymphs are a light yellowish-green color with lemon-yellow stripes on each side of the body. They pass through five molts before becoming adults, the wing-pads gradually getting larger in the later stages. No very similar insects are common on the grape, so that the pest is readily recognized. Life History. — The adult hoppers hibernate over winter under leaves, grass, or trash in or near the vineyard, in neighboring woods, along ditches or fences, etc. They emerge about May 1 in New York and at first feed on whatever succulent foliage may be available. By the time the grape foliage appears they have 458 INSECT PESTS OF FARM, GARDEN AND ORCHARD mostly emerged and infest the vineyards. These hibernating hoppers feed and breed on the lower leaves, disappearing about the time the first young become adult. After a few weeks the females commence egg-laying, which continues for about two months. The eggs are laid just beneath the surface of the leaf in groups of from six to nine, or singly, and as they are but one- thirty-fifth inch long and almost transparent, they are scarcely visible save for the eyes of the embryonic nymphs. The eggs hatch in nine to fourteen days. The young nymphs feed Uke the adults, at first on the lower leaves, but soon spread to all parts of the plant. In New York they become grown in thirty to thirty-five days, and there is but one full generation a year, with a partial second generation, most of the individuals of which probably do not mature before frost. Feeding continues until cool weather, when the adults enter hibernation. In Col- orado, New Mexico and California and probably throughout the South, there are two full generations a year. In California, according to Quayle, the nymphs from eggs laid by the hibernat- ing hoppers appear by the middle of May and the following generation of njnnphs about the middle of July. Control. — Cleaning up all fallen leaves and trash in the vine- yard during the winter, or plowing it under in the early spring, will reduce the number of hibernating hoppers, and it has been observed that they are much less numerous in vineyards where clean culture is practiced. The burning over of adjacent mead- ows, wood lots and fence rows will also be advisable where practicable. In Cahfornia, where the vines are not trelhsed, a hopper-cage, which has been fully described by Quayle, I.e., is successfully used for catching the hoppers before they commence to oviposit in the spring. In the East this could not be used, but Professor SHngerland has shown that the hibernated hoppers may be caught on sticky shields before they oviposit. However, it has been found that such methods of capturing and destroying the adults are expensive and give at best- only partial rehef from the trouble. It has been found a much better practice to kill the nymphs. This is done very efficiently by spraying them with " Black-leaf 40" at the rate of 1 to 1500, applying the spray at the time the njonphs are present in the INSECTS INJURIOUS TO THE GRAPE 459 greatest numbers on the under side of the grape leaves. If this is properly done, one application will give control. The time for spraying, in the Northern States, will generally be during the latter half of July. The Grape Leaf-folder * Very frequently grape leaves are found folded or rolled together, with the interior surface more or less skeletonized, from which a slender larva will wriggle out and fall or hang sus- pended on a silken thread. The Grape Leaf-folder occurs throughout the United States, and though usually not injurious, sometimes becomes abundant enough to do serious damage. The moth is black with white spots on the wings, and bands across the abdomen, as shown in Fig. 383. The larva is about an inch long, of a greenish-white color, with head and prothoracic shield light brown, and with brown spots on the sides of the first two thoracic segments. Life History. — "There are two broods each year in the more Northern States and three or possibly more in the South. The insect winters in the pupal stage in the folded and fallen leaves, the moths appearing in the spring shortly after the foliage puts out, and the eggs are placed in small patches here and there on the vine. Upon hatching, the young larvse attack the foliage, folding the leaves as stated. Mr. Johnson has observed that the larvae of the first brood may attack bunches of grape blossoms and young fruit in a way similar to the grape-berry moth In * Desmia funeralis Hiibner. Family Pyralidw. See Quaintance, and Quayle, 1. c, also J. F. Strauss, Bulletin 419, U. S. Dept. Agr. Fig. 383. — ^The grape leaf-folder {Desmia fun eraZis Hiibn.): «, male moth and enlarged antenna of same; 6, female moth; c, larva; d, head and thoracic segments of same en- larged; e, pupa; /, tip of pupa — enlarged; g, grape leaf folded by larva. (After Mar- latt, U. S. Dept Agr.) 460 INSECT PESTS OF FARM, GARDEN AND ORCHARD three or four weeks the larvae are full grown and transform to pupae within the folded leaves, moths emerging eight or ten days later. By midsummer and fall the insects become quite abundant, and in badly infested vineyards the folded leaves are everywhere in evidence and are quite conspicuous from the color of the lower surface. In the fall the larvae pupate in the folded leaves and pass the winter in these on the ground." — Quaintance. Control. — Where but a few larvae occur they may be crushed Nig 384.— The white-lined sphix Deilephila Inieata Fab.) : a, moth h, pale larva; c, dark form of larva; d pupa — all natural size. (After Chitten- den, U. S. Dept. Agr.) by hand, and if this is done with the first brood it will greatly reduce the numbers later in the season. Vineyards sprayed with arsenicals will be protected, as the young larvae will be killed before they fold the leaves. By collecting and burning the fallen leaves or plowing them under deeply, many of the hibernating pupae may be destroyed. INSECTS INJURIOUS TO THE GRAPE 461 Hawk-moth Larvae * Several species of Hawk-moth or Sphinx-moth larvae are com- monly found on the vine. Most of them are widely distributed throughout the country and feed on wild grape and Virginia creeper. Usually they are not numerous enough to do serious Fig. 385. — The achemon sphinx (Pholus achemon Dru.): a, moth; b, egg; c, young larva; d, mature larva; e, pupa; /, parasitized larva — all natural size. (After Marlatt, U. S. Dept. Agr.) damage, and as they strip a branch at a time, they are readily seen and may be destroyed before much injury is done. Occasionally, * Family Sphingidce. See O. Lugger, 4th Report State Ent. Minn. ; lad M. Eliot and Caroline M. Soule, "Caterpillars and their Moths." (N. Y., 1902). 462 INSECT PESTS OF FARM, GARDEN AND ORCHARD however, one or two larvae may entirely strip a young vine, and exceptionally the larvae appear in considerable numbers on old vines, stripping them bare of foliage. They are large, smooth- bodied larvae, 2 to 3 inches long, and may be distinguished from those of other famiUes of moths by the strong horn on the next to the last segment, which has given them the common name of horn-worms. In many species, this horn is present only in the first one or two stages of the larva, disappearing with the next molt and being replaced by a bright eye-spot, as shown in Fig. 385, c, d. The life history of the various species is much the same, except that some have only one, while others have two genera- tions a year in the North, though most all probably have two generations in the South. They hibernate as large dark-brown pupae, 3 or 4 inches below the surface of the ground, and the moths emerge in spring. The moths are particularly attracted to petunias, and may often be caught hovering over them at night. The eggs are laid on the foHage, usually singly, and the larvae hatch in a few days. They eat ravenously, and will con- sume an enormous number of leaves within a few days. Usually the coloration of the larvae changes more or less as they grow, so that when full grown they are different from the younger stages. When there are two generations, the second generation of larvae will appear in late July, but whether one or two generations occur, the larvae maturing in late summer transform to pupae which hibernate. Control. — Usually the work of the larvae is so conspicuous and they are so easily found that they may be controlled by hand- picking. Where the vineyards are sprayed regularly for other pests there will be but httle trouble with these larvae, as they will, be killed while young. The Grape-berry Moth * The larvae of the Grape-berry Moth are the most common cause of wormy grapes. The first generation of larvae web together the grape clusters before the blossoms open or soon after the grapes are set, and feed upon the clusters. Later the larvae bore into the green and ripening fruit, producing purphsh spots * Polychrosis viteana Clem. Ysimily Tor tricidce. See Quaintance, I.e.; Hartzell, I.e.,; M. V. Siingerland, Bulletin 223, Cornell Univ. Agr. Exp. Sta.; Gossard and Houser, Circular 63, Ohio Agr. Exp. Sta. Dwight Isely, Bulletin 550, U. S. Dept. Agr. and W. H. Goodwin, Bulletin 293, Ohio Agr. Expt. Sta. INSECTS INJURIOUS TO THE GRAPE 463 resembling the appearance of injury by the black rot. The berries decay from the work of the larvae and from the entrance of fungous diseases. The insect occurs throughout the United States, but has been particularly injurious in the Chautauqua, N. Y., Erie, Pa., and Northern Ohio grape belts. So far as known the grape is the only food-plant and the species is a native one. though its habits are very similar * ||^ to a nearly related European ^ species. ^ The adult is a little purplish- '^ _^ brown moth, with wings expand- '— SUSHl^r ing not quite one-half inch, and ^^,>-»4^^^^^mLtjm 4 "^ ■■■•■?«^ Fig. 386. — The work of the grape-berry moth; infested cluster and single berry opened to show larva at woi"k — enlarged. (After Slingerland.) shaded with brownish markings as shown in Fig. 387. The ground color is lilaceous or leaden-blue and the spots are dark brown. Life History. — The moths appear in the spring as the shoots of the grape are pushing out, and continue to emerge for some weeks. The earlier ones lay their eggs on the blossom clusters, while the later ones deposit them on the young grapes. The minute flat, scale-like eggs are stuck to the surface of the stems or berries, and look like small glistening, whitish spots. The little larvae hatching from them feed on the blossoms and small berries, webbing the clusters together, and might do much more damage than the later generations were it not that they are much fewer in number, there being a great mortality of the insects over winter. The larvae become full grown in about three weeks. The mature larva is about three-eighths inch long, varying in color from dark greenish to dark purplish, with a light-brown Fig. 387. — Grape-Berry Moth: 1, Larva; 2, Pupa (ventral aspect) in cocoon; 3, Pupa (dorsal aspect.); 4, 5, Adult. All greatly enlarged. (After Isely, I.e.) 464 INSECTS INJURIOUS TO THE GRAPE 465 head and black thoracic shield. The body is covered with numerous faintly outlined darker spots, from which arise whitish hairs. The larva cuts out a piece of a leaf on three sides, folds it over and fastens the free edge to the leaf with silk. The fold is then lined with a thin layer of silk, making a thin cocoon in which it transforms to a light greenish-brown pupa, from which the moth emerges twelve to fourteen days later. The moths of the second and later generations place their eggs on the berries and the larvae bore into them and feed on the pulp and seeds. In New York the moths of the second generation appear in early /■> Fig. 388. — Grape leaf showing cocoons in the making and finished by grape- berry moth caterpillars — natural size. (After Slingerland.) July and the second generation of larvae occurs during July and August. In New York those larvae of the second generation which mature before mid-August pupate and give rise to a third generation, while those maturing later transform to pupae, but hibernate. Often there is nearly a complete third brood in that latitude, and farther south there are undoubtedly at least three generations. The winter is passed in the pupal stage in the cocoons, which break off from the fallen leaves. Control. — Infested berries should be picked off both to destroy the larvae and to prevent the spreading of fungous diseases. 466 INSECT PESTS OF FARM, GARDEN AND ORCHARD Plowing under the fallen leaves either in fall or early spring should result in burying many of the pupse so as to prevent the escape of the moths, and is good practice for other grape pests. The principal reliance should be placed upon spraying with arse- nate of lead, 3 pounds per barrel, applied with Bordeaux mixture, to which a soap "sticker" should be added to make the mixture more adhesive to the berries. The first spraying should be made before the blossoms open, to catch the early larvae; the second should be made as the grapes finish blooming; and the third, early in July. The addition of the "sticker" is most important in the last spraying, when the berries are partly grown. The spray must be appHed with sufficient number of nozzles and pressure to penetrate the foliage and cover the clusters thoroughly. Isely (I.e.) shows conclusively that it is much more satis- factory to apply the spray by hand with short leads of hose and short spray rods, called trailers, than it is to depend upon any fixed arrangement of the nozzles which does away with the hand work. Difference in efficiency between the two methods favored the trailers by from 15 to 20 per cent and more than! repaid the extra cost. To preserve some clusters in extra fine condition or to pro- tect grapes on a small number of vines, paper bags are some- times tied over the clusters as soon as the berries have set. The Grape Curculio * The larvae of the Grape CurcuHo feed on the pulp and seeds of the berries, causing wormy grapes, much as do those of the berry-moth. The larvae may be readily distinguished, for those of the curcufio are white, footless grubs, while those of the berry- moth are greenish, with well-developed legs, and are quite agile, wriggling away quickly when disturbed. The adult curculio is a small, brown, robust, snout-beetle about one-tenth inch long, and nearly as broad. It is very difficult to see, looking like a bit of dirt or the excreta of some of the larger caterpillars common on the vine. It is common from Arkansas to Minnesota east- ward to New York and North CaroHna. It has been particularly injurious in West Virginia, and seems to be most harmful in that latitude. * Cra-ponius inoequalis Say. Family Curculionidce. See Quaintance, I.e., and Fred E. Brooks, Bulletin 100, W. Va. Agr. Exp. Sta. INSECTS INJURIOUS TO THE GRAPE 467 Life History. — The beetles hibernate over winter in or near the vineyards, especially along the edge of woodlands. They appear in the spring about the time the grapes blossom and feed upon the foliage for three or four weeks until the berries are Fig. 389. — The grape curculio {Cra'ponius incEqualis Say): a, beetle; h, head of same from side; d, larva from above; e, same from below; /, pupa — all much enlarged. (After Quaintance, U. S. Dept. Agr.) about one-fourth grown. The beetles cut small characteristic holes in the loaves, and this habit of feeding on the foliage so long makes it possible to kill them with arsenicals before oviposition is commenced. In West Virginia the females begin egg- laying late in June, most of the eggs being laid in early July, but egg-laying may continue for eighty-one days, during which time a female will lay an average of 257 eggs. The female excavates a small cavity in the berry in which the egg is placed and hatches in four to six days. Infested berries often show a purphsh spot around the egg- puncture. The larva bores in the pulp and in three or four days reaches the seed, which is then devoured. The larva becomes full grown in twelve to fifteen days, when it eats its way out of the berry and drops to the.ground in search of a suitable place to pupate. The mature larva is white, about one-third inch long, tapering from the middle of the body toward either end, without legs, and clothed with fine short hairs. The larvjB make small earthen cells under stones. Fig. 390. — The grape cur- culio in act of egg-lay ing — natural size ; e, showing position of egg in grape — enlarged. (After Brooks.) 468 INSECT PESTS OF FARM, GARDEN AND ORCHARD lumps of earth or just below the surface of the soil, and in them transform to pupae, from which the beetles emerge in eighteen to nineteen days. Thus the com- plete life cycle from egg to adult requires thirty-five days. The hibernating beetles are still abroad when the new beetles appear, and Brooks states that the average life of a beetle is one year and nineteen days. Although the beetles of the new brood lay some eggs, but few of them develop, and in West Virginia there is practically but one generation, although farther south a second generation may occur. The beetles feed until fall, when they enter hibernation. Control. — As the beetles feed so long on the foliage in early Fig. 391. — Grape curculio larvae — natural size. (After Brooks.) Fig. 392. — Grapes showing egg-punctures of grape curculios. (After Brooks.; summer they may be readily killed by spraying with arsenicals as advised for the berry-moth and grape-root-worm beetle. I 3 • Fig. 393. — Showing the resemblance of the grape curculios at 2 to excrement of sphinx caterpillars at 1, and mummied grapes at 3. (After Brooks.) INSECTS INJURIOUS TO THE GRAPE 469 Thorough cultivation in midsummer would doubtless destroy some of the pupae in the same manner as in the case of the root- worm. Infested fruit may be collected and destroyed as for the berry-moth with equally good results. Where spraying is regularly practiced there probably will be httle need of resort to other methods. CHAPTER XXIV SOME INSECTS INJURIOUS TO ORCHARD FRUITS* The San Jose Scale f Probably the most serious of all the insect pests of the orchard is the San Jose Scale, for it will kill young trees in two or three years, and old trees must be sprayed annually to keep it under control. So insidious is the attack of the pest to those unfamiliar with it that it has killed many thousands of trees before the owners suspected its presence. It may be most readily detected on the fruit, which becomes spotted with small red circles which form around the scales, but usually the fruit is not attacked until the tree is badly infested. On the young twigs and along the veins of the leaves a similar reddish discoloration appears around the scales. The trunk and branches covered with scales have a rough grayish appearance, as if they had been coated with dark ashes. By scraping the surface the soft, juicy, yel- lowish insects will be revealed beneath the covering scales. If a single female insect be examined it will be found that it is covered by a small, circular scale, varying from grayish to blackish in color, formed of concentric circles, the centre of which is quite convex and forms a "nipple," which is yellowish and shining when the surface is rubbed off. If this scale be raised with a pin, beneath it may be seen a small, soft, oval, orange-colored object, which is the true female insect. She is an almost shape- less mass of protoplasm, lacking head, legs and eyes, only the thread-like mouth parts and anal plate being distinct. The scale itself is merely a waxy covering secreted by the insect beneath. The scale of the male is smaller and somewhat elongated, the nipple being at the larger end. * See Quaintance and Seigler, Farmers' Bulletin 908, U. S. Dept. Agr. IfAspidiotus perniciosus Comstock. Family Coccidce. See C. L. Mar- latt, Bulletin 62, Bureau of Entomology, U. S. Dept. Agr., and the numer- ous publications of many of the experiment stations, listed in his bibliography. 470 INSECTS INJURIOUS TO ORCHARD FRUITS 471 Injury by this species was first noticed near San Jose, Cal., about 1880 where the scale was most destructive and was inves- tigated by Professor J. H. Comstock, who first described it. About 1887 it was brought east on Japanese plum trees secured by Eastern nurseries and was distributed by them on young Fig. 394. — Peach twigs infested with tiic .Nin Jose scale. On the twig at the right a scale has been turned back showing the female insect — enlarged. (After W. E. Britton.) trees, so that in 1893 it was discovered in orchards in Maryland and Virginia. Since then it has been spread on nui'sery trees to practically every State. Investigations made by C. L. Marlatt in 1901 showed that the insect is undoubtedly a native of east- 472 INSECT PESTS OF FARM, GARDEN AND ORCHARD central China, and was probably brought to this country on flowering-peach or some ornamental plant. Life History. — The winter is passed by partly grown insects under the scales, which begin to feed with the bursting of the buds in spring. In the latter part of April the insects have become full grown in the District of Columbia, and the males emerge and fertilize the females. The male is a small, yellowish, two- winged fly. The males emerge at night and are so small they are seldom seen unless reared. About a month later the females com- mence to give birth to live young and continue to do so for some six weeks. This species differs from most scales in having no egg stage, the eggs hatching in the body of the female. The young insects are very small, yellowish in color, and resemble small mites. They have six legs, a pair of antennae, and a long thread-Hke beak through which the food is sucked, as shown in Fig. 398. The young insect moves about freely for from twelve to thirty-six hours, then thrusts its beak into the bark or fruit, and if a female does not move again. White, waxy filaments soon exude from over the body, and in a couple of days the insect is entirely T^ or>r Ti •• J 1 ^u covered by them, and as they mat down Fig. 395. — Pear injured, by the , "^ ' , '^ . San Jose scale showing the a scale is formed which conceals it. This discolored spots. young scale is whitish with a prominent nipple in the center. After the first molt, the females lose eyes, legs, and antennae, for which they have no further use. Nour- ished by the sap of the plant the insect develops rapidly and is full grown in about a month. In the District of Columbia there are four or five generations a year, in the South there are probably more generations, while at the northern hmit of the species there are two or possibly three generations, as breeding continues until after killing frost. As with other small insects, it is the remarkable power of reproduction to which the destructive- ness of the pest is due. Thus it has been estimated that at Wash- ington, D. C, the progeny of a single female would number 3,216,080,400 by fall, if ah were to survive. It is not surprising. INSECTS INJURIOUS TO ORCHARD FRUITS 473 tnerefore, that a tree with but a few scales on it in spring will be covered by them and the fruit unfit for market in the fall, Fig. 396. — Peach leaf bearing ^an. Jos6 scales along veins. and that with these millions of little beaks pumping out the sap and poisoning the tissues a tree soon succumbs. The pest has been spread mostly by being transported on nursery trees. Trees infested from the nursery will usually have more scales on the lower trunk, from which they will spread to the limbs, while those infested from neighboring trees will have more scales on the young wood. Where the pest is abundant the young insects are undoubt- edly blown from tree to tree by the wind, or they may be carried on the feet of birds or insects, or brushed off and carried by persons or teams workmg in the orchard. The insect has been found on a long list of plants, but on many of them it is largely accidental. Injury is practically confined to plants of the Rosace ce, which family includes all our common deciduous fruits. Of the orchard trees peach, pear, Japanese plum, apple and quince are most injured in the order named, while cherry and European plum are less injured. Control. — As yet no spray has been found for use in summer which will more than check the increase of the pest without injury to the tree, and summer spraying is resorted to only when Fig. 397.— Adult female San Jos6 scale, with scale removed to ex- pose the insect. (After Alwood.) 474 INSECT PESTS OF FARM, GARDEN AND ORCHARD winter treatment has been neglected or has proven inefficient. 10 or 15 per cent kerosene emulsion, dilute miscible oils, dilute lime-sulfur mixture, or whale-oil soap, 1 pound to 4 or 5 gallons, may be used for summer spraying. On the Pacific Coast trees are very generally fumigated with hydrocyanic acid gas * for this and other scale insects, but the Fig. 398. — Young larva and developing San Jos6 scale (Aspidiotus pemiciosus Comst ) : a, ventral view of larva, showing sucking beak and setse sepa- rated, with enlarged tarsal claw at right; h, dorsal view of same, still more contracted and with the first waxy filaments appearing; c, dorsal and lateral views of same, somewhat contracted, illustrating further development of wax secretion ; d, later stage of the same dorsal and lateral views, showing matting of wax secretions and first form of young scale — all greatly enlarged. (After Howard and Marlatt, U. S. Dept. Agr.) treatment has never come into favor in the East, principally, perhaps, because of the larger trees and the more scattered nature of the fruit industry. Practically the only methods now used in the East consist in spraying the dormant trees with washes which penetrate the scales and destroy the insects. This may be done more effec- *See C. W. Woodworth, Bulletins 122 and 152, Cal. Agr. Exp. Sta.; R. S. Woglum, Bulletins 79 and 90, Bureau of Entomology, U. S. Dept. Agr. INSECTS INJURIOUS TO ORCHARD FRUITS 475 tively if the trees are pruned and headed in so as to reduce the wood to be covered. Rough bark should be scraped off so that the scales beneath may be reached. Badly infested trees should be sprayed in the early winter as soon as they have hardened up and again in the spring just as the buds commence to swell. The spring spraying will suffice for trees slightly infested. Every bit of bark on the tree must be thoroughly wet, so none will escape. Lime-sulfur mixture seems to be the favorite wash for winter spraying at present, as it not only kills the scale, but aids in the control of many fungous diseases. Miscible oils are also exten- sively used and have a certain advantage on hairy apple shoots and on badly infested trees, as they are more penetrating and spread better. Kerosene or crude oil emulsion containing 20 to 25 per cent of oil was the first remedy to be used and is still extensively employed. Whale-oil soap, at the rate of 2 pounds to the gallon, applied hot, is effective, but is too expensive for large users. The Fruit-tree Bark-beetle * If the outer bark is punctured by numerous small ''worm- holes" so that it looks as if it had been struck with a charge of bird-shot, it indicates the presence of the fruit-tree bark-beetle or some nearly related species (see p. 477). Usually more or less gum exudes from the holes, particularly on stone fruits. Diseased or weak-growing trees are most subject to attack, but occasionally serious damage is done to perfectly healthy trees, especially when young. Injury is largely due to allowing dead and dying trees to stand in the orchard, thus encouraging the breeding of the pest in them and its spread to healthy trees. "Another form of injury is the destruction at the beginning of spring of small twigs, together with the leaves which they bear. The beetles are also reported to destroy leaves by boring into the base of the buds at their axils." The holes in the bark are caused by the exit of the small parent beetles and by their subsequent entrance to deposit eggs. The adult beetle is about one-tenth inch long, by a third as wide, and of a uniform black color, except the tips of the wing-covers and parts of the legs, which are red. * Ecoptogaster rugulosus Ratz. Family Scolytidce. See F. H. Chittenden Circular 29, Division of Entomology, U. S. Dept. Agr., and F. E. Brooks, Farmers' Bulletin 763, ibid., H. A. Gossard, Bulletin 264, Ohio Agr. Exp. Station. 476 INSECT PESTS OF FARM, GARDEN AND ORCHARD Life History. — The beetles emerge from the trees in April and May in the Middle States. The female burrows through the bark, and partly in it and partly in the sap-wood she eats out a vertical gallery or brood chamber, along the sides of which at short intervals she gnaws out httle pockets in which she places her eggs. The larvse hatching from these eggs excavate Uttle side galleries, which branch out and widen as the larvae increase Fig. 399. — One of the most important native enemies of the San Jose scale, a little black ladybird-beetle (Microweisea misella): a, beetle; b, larva; c, pupa; d, beetles, larvae, and pupae, among scales — all greatly enlarged. (After Marlatt, U. S. Dept. Agr.) in size (Fig. 401). The larvse become mature in about three weeks, when they form cells at the ends of their burrows and transform to pupae, from which the adult beetles emerge about a week later. There are probably three generations a year in the Middle States according to Dr. Chittenden. Were it not for the effective work of parasitic and predaceous insects which prey upon it, this insect would be a most serious pest. One of the most valuable of these is a little chalcis-fly * of which Dr. Chittenden bred 92 specimens from 72 of the develop- * Chiropachis colon Linn. INSECTS INJURIOUS TO ORCHARD FRUITS 477 ing beetles, and we have frequently had twigs in which practically all of the developing beetles were parasitized. Fig. 400. — ^The fruit-tree bark-beetle (Scolytus 7-ugulosus): a, h, beetle; c, pupa; d, larva — enlarged. (After Chittenden, U. S. Dept. Agr.) ControL- The most important point in the control of this and similar pests is to cut out and de- stroy all dead and diseased wood. Burn all prunings and trimmings. Affected trees should be Hberally fertilized m the spring so that they may make a quick growth and better withstand the in- jury. Repellant washes have been advised for deterring the beetles from ovipositing. A thick soap wash containing a pint of crude carbohc acid to 10 gallons may be used. Professor Gossard advises whitewashing the trees in early spring, again in mid-summer and lastly about October 1st, adding one-quarter pound of table salt or some Portland cement to make it more adhesive. He also reports kilhng the beetles in their burrows with an emulsion of carbolineum. "Emulsify by dissohang 3 pounds of naphtha soap in 3 gallons of water by boihng. While hot, add 1 gallon of carbolineum (avenarius) and agitate as for Fig. 401.— Work of the fruit-tree bark-beetle showing the main gal- leries, the side or larval galleries, and the pupal cells — slightly en- larged. (After Ratzeburg.) 478 INSECT PESTS OF FARM, GARDEN AND ORCHARD kerosene emulsion with a force pump. Add four gallons of water for use and apply with a spray pump. Keep face and hands protected from this spray." The carboHneum is rather expensive, however, and does not seem to be much more effective than the whitewash. Control measures, aside from pruning, are rarely necessary. The Buffalo Tree-hopper * The work of the Buffalo Tree-hopper consists of a series of cuts or incisions in the Umbs of fruit or shade trees, made by the female in the process of egg-laying, which result in very character- FiG. 402. — The buffalo tree-hopper (Ceresa huhalus Fab.) : a, a, adult, enlarged and natural size; twig of apple showing recent egg-punctures at h; c, bark reversed with eggs in position; d, single row of eggs — enlarged; e, wounds of two or three years standing on older limbs. (After Mar- latt, U. S. Dept. Agr.) istic wounds. This injury is somewhat like that done by the periodical cicada or by tree crickets, but the scars are larger and are placed irregularly. When badly attacked the hmbs of small trees sometimes become so scarred that they are badly stunted or may be killed. The cause of this mischief is a curious * Ceresa huhalus Fab. Family Memhracidce. See C. L. Marlatt, Circular 23, Div. Ent., U. S. Dept. Agr., and H. E. Hodgkiss, Tech. Bulletin 17, N. Y. Agr. Exp. Sta., p. 92. INSECTS INJURIOUS TO ORCHARD FRUITS 479 little grass-green insect, about three-eighths inch long, whose pronotum is broadly expanded into two sharp horns, which are fancied to be like those of the buffalo, as indicated by the common name of the insect. They are very common, frequenting all sorts of rank-growing vegetation, appearing in midsummer, and being most numerous in August and September. Life History. — Egg-laying is commenced in August and is continued until killing frosts. The eggs are laid in two curved slits, with from six to twelve in each, as shown in Fig. 402, c, d. In making these slits the female cuts the bark between them entirely loose, so that the intervening wood soon dies, possibly to prevent the growth of the wood crushing the eggs. A large scar is thus formed which enlarges with each season's growth, and finally becomes an oval shape by the center dropping out. After a few years badly infested limbs become very rough, are easily ^'k'^I^^T^I^P^ ""^ broken by the wmd and furnish van- bunalo tree-hopper — . enlarged. (After tage pomts for the attack of borers. Hodgkiss.) rpj^g gggg hatch the next May or June. Like the adults, the young nymphs feed on all sorts of succulent vegetation, seeming to prefer the juicy annual plants even to the tender terminals of trees, the orchards suffering most being those grown up in weeds. Control — By keeping young orchards well cultivated and free from weeds, the nymphs will have no food in early summer and will starve or leave for better feeding grounds. Patches of weeds near young orchards should also be destroyed. When trees are badly wounded by the egg punctures they should be well pruned and the prunings burned to destroy the eggs. The Periodical Cicada * " There is probably no insect that has attracted more general interest and attention in this country than the Periodical Cicada, or the so-called Seventeen-year Locust. The earliest settlers * Cicada septendecim Linn. Family Cicadidoe. See C. L. Marlatt, Bul- letin 71, Bureau of Entomology, U. S. Dept. Agr.; A. D. Hopkins, Bulletin 68, W. Va. Agr. Exp. Sta. 480 INSECT PESTS OF FARM, GARDEN AND ORCHARD doubtless associated its vast noisy swarms with the devastating invasions of the Migratory Locust of the East. Hence the popular name locust, which has been used so long that it is doubtful if it will ever be discarded for the proper name — Periodical Cicada." They are quite different from the true locusts, or grasshoppers, however, for the latter have biting mouth-parts while the cicadas suck the juices of the plant through a tube-like beak. Some twenty-seven distinct broods of the cicada have been distinguished, seventeen of which appear at seventeen-year intervals and ten of them appear at thirteen-year intervals, the former being mostly Fig. 404. — The periodical cicada {Cicada sepiendecim Linn.): a, adult; b, young nymph — enlarged; c, cast skin of full grown nymph; d, adult females showing ovipositor at b, and beak at a — natural size. (After Marlatt and Riley, U. S. Dept. Agr.) in the North and the latter mostly in the South. Some one or more of these broods appears in every State east of the Rockies except Maine, New Hampshire and Vermont. Every year there is a brood emerging in some part of the country, and the different broods have been carefully mapped so that their emergence may be anticipated. Life History. — The adults appear in immense swarms in late May or early June. "About four or five days after their first appearance," says Dr. Hopkins, "the males begin to sing," filling the air with their shrill calls, which are produced by two drum-like membranes on the under surface of the first abdominal INSECTS INJURIOUS TO ORCHARD FRUITg 481 segment. "About eight or ten days later the sexes begin to mate, and in about four or five days more the females commence IT Fig. 405. — Typical cicada injury. Photo by W. E. Rumsey to deposit eggs. Each female is said to deposit from three to five hundred eggs in numerous ragged punctures made by her Fig. 406. — Emergence of cicada. powerful ovipositor in the twigs of shrubs and trees, and some- times in the stems of herbaceous plants. These hatch in about 482 INSECT PESTS OF FARM, GARDEN AND OJICHARD six or eight weeks from the time they are deposited and the young cicada larvae emerge and fall to the ground. They then burrow beneath the surface and enter upon their long menial existence in the ground, feeding on the liquids of roots and possibly sub- sisting on such nutriment as may be obtained from the soil itself. They change their position from time to time, and may rarely enter the earth for a distance of eight to ten feet or more," though usually within two feet of the surface. ''By the twelfth or thir- FiG. 407. — The full-grown nymphs of the periodical cicada in different stages of molting and the newly emerged adults with body and wings still soft and white. teenth year the larva attains its full growth and in time changes to the intermediate or pupa stage.* During the spring of the fifteenth and sixteenth years great numbers of the pupae may be * Dr. Hopkins and other writers commonly use the terms larva and pupa in describing the immature stages of the cicada, but there seems no reason for discarding the term nymph used for other Hemiptera, and which is cer- tainly useful in distinguishing the immature stages of insects with incom- plete metamorphosis from those with complete metamorphosis which have a true pupa. INSECTS INJURIOUS TO ORCHARD FRUITS 483 found near the surface, and a few individuals may emerge during May and June of the sixteenth year. Early in April of the seven- teenth year the pupae commence to make preparations to emerge from the ground by excavating burrows or exit galleries to the surface. These exits are completed by the last of April. Ordinarily they extend only to the surface, and are kept open from a depth of a few inches to a foot or more. In some soils these exit holes are extended four or five inches above the surface by means of clay carried up from the subsoil, and are called cicada chimneys. The pupae come from the ground in the evening and at night, usually between sundown and ten o'clock, and proceed to the nearest upright object, which may be a tree, the side of a building, fence, or weed stem — anything, in fact, upon which they can chmb and expose their bodies to the action of the open air. In about an hour after emerging the skin on the back splits open and the adult insect works its way out (Fig. 406). The wings, which are short and soft at first, rapidly develop; the body, wings and legs harden, and by the following day the adult is ready to take flight and enter upon its short aerial life, limited to about thirty days. During this short period they feed but httle, if at all, the males devoting their time during the day to flying about and making a noise, ^^^,- ^^?T~^°u"^, ^^^^ , . , . , , shrouded with cheese while the voiceless females busy themselves cloth to prevent cicada depositing eggs. " If the young nymphs do injury. Photo by W.E. any injury to the roots of trees or plants, it is very rarely perceptible. The adult females, however, are capable of causing serious injury to young fruit trees in orchards and nurseries by the numerous punctures in the twigs, limbs and main stems made by them in the act of ovipositing The egg puncture makes an ugly wound, beyond which the twig dies, and the foliage of large trees on which hundreds of cicadas have 4^ i^ ' m '. 'ij mM ,\ vHhH 1 ' 1 1 wS^f \ ^^^^M H m '^i^H 1 Hi '/MU 1 484 INSECT PESTS OF FARM, GARDEN AND ORCHARD I^^Ji^HMr- ->—»■-.. • ^- - '^^g/KP ^^■P^' - j^Tj^Sfl^- ^Ec ^^^p^- l^^^/'M^ ^^^B~ jl^^^p^. "^^nr^BI Ek "'"^I^^BHp mpi^ Fig. 409. — Result of protecting trees with cheese- cloth. Above, protected trees at end of the season; below, unprotected tree at the same time. Photos by W. E. Rumsey. oviposited turns, brownasif the tree had been scorched by fire. On young trees this results in destroying the growth of a year or two and misshaping the tree, and the scars which remain later furnish points of attack for borers and the woolly apple-aphis. Just before the cicadas leave the ground they are at- tacked by hogs and also by disease. Upon leaving the ground they are at once assailed by a host of predaceous insects and various animals. One of the most valuable insect enemies is a large wasp (Sphecius speciosus Dru.), which may often be seen bearing the adults to its burrow, where they furnish food for her young. The English sparrow is remarkably fond of the adults and is the most valuable factor in exterminat- ing them in cities and towns. It has been noticed that cicadas are much more likely to emerge from newly INSECTS INJURIOUS TO ORCHARD FRUITS 485 cleared land, and with the removal of the forests and cultivation of the land they are undoubtedly becoming more scarce. Control. — There is no means of destroying the adults, but many of the pupae may be destroyed by allowing hogs to run on land known to be infested during April and May of the year they emerge, where it is feasible to do so. Injury to young orchards may be avoided by not planting during the year or two previous to the emergence of a brood in the particular locality. Budding and grafting should also be avoided dm-ing the previous spring. Orchards should not be pruned the year before a cicada- year, so that there may be plenty of young wood in which they may oviposit and which may then be removed without injury to the tree. Evidently a knowledge of the time of appearance of each brood in different sections is of great importance and may be secured from the maps pubhshed (see Marlatt, I.e.). After all the eggs are laid the affected twigs should be pruned off in July and burned before the eggs have hatched. Newly planted trees may be protected to a large extent by wrapping them in cheesecloth during the presence of the adult cicadas. The method has been tried in West Virginia and in Virginia and the benefits have been sufficient to warrant the necessary expenditure. The Fall Webworm * The common Fall Webworm is so called because in the North, where there is but a single generation, its webs are abundant in August and September, in contrast to those of the tent cater- pillar, with which they are often confused, which are found in the spring. The wings of the adult moths expand from one to 1 1 inches, and are either a pure milk-white, or more or less spotted with black, the number of spots being exceedingly variable. The full grown caterpillars are about an inch long, covered with long black and white hairs which project from numerous black tubercles. They are also quite variable in color, some being uniformly yellow- ish with black and yellow tubercles, while others have a dark stripe down the back and are almost black. Life History. — In the North the moths emerge late in June and in July, and lay the eggs late in July. The eggs are deposited on the leaves in pale yellowish-green patches of 400 to 500, often * Hyphantria cunea Dru. Family Arctiidoe. 486 INSECT PESTS OF FARM, GARDEN AND ORCHARD covered with whitish down from the body of the female, and hatch in about ten days. The young larva are pale yellowish with brown markings and appear to be almost all head and hair. They at once spin a web over the foliage on which they are feed- ing, those from one egg mass feeding together and enlarging the F - ^ ■ ' ■' 9 ') 1 f CI # \ Fig. 410. — The fall webworm (Hyphantria cunea Dni.): a, light form ,of full-grown larva; h, dark form of same; c, pupa; d, spotted form of moth — all slightly enlarged. (After Howard, U. S. Dept. Agr.) web as necessary. In the North the webs are usually noticed in early August and are started at the tips of the limbs. Within them the surfaces of the leaves are eaten off until they are left dry and brown. When all the foliage on a limb has been consumed, the caterpillars leave the web, enclosing the dead leaves, and form a new web on a fresh branch, and thus the tree soon becomes covered INSECTS INJURIOUS TO ORCHARD FRUITS 487 with unsightly webs, which are often mingled so that the whole tree is webbed over. The web is easily distinguished from that Fig. 411. — Web of the fall webworm on apple, showing enclosed foliage and larvae feeding within. 488 INSECT PESTS OF FARM, GARDEN AND ORCHARD of the tent caterpillar, as it is found later, and the tent caterpillar makes a relatively small web in the fork of a limb and never encloses foliage in it. The caterpillars become full grown in a month to six weeks, and then find secluded places under the bark or in a hollow of the tree, in the rubbish at its base, or in a fence corner, or sometimes just under the surface soil, and there spin flimsy silken cocoons with which they mingle their own hairs. They then transform to small brown pupae about one-half inch long, in which stage the winter is passed. In the Middle States and farther south there are two genera- tions, the moths ap- pearing in April and May and laying eggs in late May and early June, the caterpillars from which becomefull grown by mid-July. The second generation of caterpillars appears in late August and September at about the same season as farther north, and their pupse hibernate. Were it not for their parasitic enemies these Fig. 412.^ — Meteorus hyphanirice, a common para- site of the fall web worm; a, adult female; b, empty cocoon showing cap and suspending thread — enlarged. (After Riley, U. S. Dept. Agr.) caterpillars would be much more of a pest, and it is when the para- sites become scarce that injury results. One of their most com- mon and effective enemies is a little Braconid fly,* whose small brown cocoon (Fig. 412) is often found suspended from a twig or leaf. Many caterpillars are also killed by various predaceous bugs, and frequently they are killed off by fungous disease The fall webworm is a common pest of all orchard trees, and frequently extends its injuries to shade trees. The larvae are not uncommon on cabbage, beets and a long list of garden crops. According to Dr. H. G. Dyar this species is confined to the South * Meteorus hyphantrioe Riley. INSECTS INJURIOUS TO ORCHARD FRUITS 489 Atlantic States, but it has been confused with another species (Hyphantria textor Harris) by practically everyone, and it is still a question as to whether the two species are really distinct and if so how they are to be distinguished. If the latter form be a distinct species, it occurs throughout the United States and has the same habits. Control. — The insect is readily controlled by spraying with any of the arsenicals when the work of the young larvae is first noticed. Where orchards are sprayed for the codling moth there will be little trouble with the first generation, and fruit-growers will do well to make it a practice to spray in August where they are troubled with this and other leaf-eating caterpillars. Mechanical destruction of the nests is good practice when spray- ing is not done. The Brown-tail Moth.* The Brown-tail Moth has become injurious only in Massachusetts, New Hampshire and Maine although it has several times been brought into other states in the winter nests on seedling trees imported from France and Belgium. With the present effici- ent quarantine service it is rather unlikely that it will become estab- lished elsewhere. On the contrary, it seems that its range may gradu- ally be reduced although actual exter- mination can not be looked for in the immediate future. It has long been a serious pest in parts of central and western Europe, whence it was introduced into Massachusetts about attention until 1897. Fig. 413. — Winter web of the brown-tail moth — one-half natural size. 1890, but did not attract The female moth is pure white except the tip of the abdomen, which is golden brown and forms a large * Euproctis chrysorrhcea Linn. Family Liparidce. See L. O. Howard, Farmers' Bulletin 264, U. S. Dept. Agr.; E. D. Sanderson, Bulletm 136, N. H. Agr Exp. Sta.; A. F. Burgess, Farmers' Bulletin 845, U. S. Dept. Agr, 490 INSECT PESTS OF FARM, GARDEN AND ORCHARD tuft or brush, which gives the insect its name. The wings of the female expand 1| inches, the males being slightly smaller, and bear one or two streaks of brown on the under sides. The full-grown caterpillar is 1| inches long, dark brown, marked with a white dash on the side of each segment. The body is dark brown or blackish, well marked with patches of orange and covered with numerous tubercles bearing long barbed hairs. On the centre of the fifth and sixth abdominal segments are small retractile red tubercles. The tubercles along the back and Sides are thickly covered with short brown hairs which give them a vel- vety appearance. These microscopic hairs are barbed and are the nettling hairs which, when they alight on the skin, produce a dermatitis much like that caused by poison ivy. As the cast skins are carried here and there by the wind and the young caterpillars drop from the trees, people are frequently badly poisoned where the pest becomes abundant, so that it is a serious public nuisance as well as as defoliator of fruit and shade trees. The caterpillars prefer fruit trees, pear, wild cherry, and apple being most relished, but become abundant on almost all the common shade trees, except the evergreens, and particularly on oak. Life History. — The moths emerge in midsummer. They are strong fliers and are readily carried by the wind for many miles. They are attracted to lights in great numbers, so that they are more abundant in cities and villages. Late in July the eggs are laid on the terminal leaves, 300 or 400 being laid in an elongate mass and covered with brown hairs from the tip of the female's abdomen. They hatch in about three weeks and the young larvae feed on the surface of the leaves, leaving only the brown skeletons, so that badly infested trees turn brown in early fall. The cater- FiG. 414. — Winter web of the brown-tail moth bearing young larvte which have emerged before the fohagehas appeared and are feeding on the dead leaves of the nest — two-thirds natural size. INSECTS INJUEIOUS TO ORCHARD FRUITS 491 pillars hatching from an egg mass feed together on adjoining leaves, which they soon commence to draw together with silken threads, and by the first frosts they have spun them into a tough web. This is attached to the twig by the old leaf stems, which are bound to it by silk. The web looks like a couple of dead leaves from a distance, but the leaves are merely the outer covering, and if the silk web be torn Fig. 415. — Full-grown larvae of the brown-tail moth — natural size. open, there will be found numerous small pellets of silk each enclos- ing from three to twelve of the little partly grown caterpillars. The caterpillars emerge just as the buds burst in the spring and feed on the expanding foliage. Where abundant they soon strip a tree, for each of the nests harbors 400 or 500 little caterpil- lars. In five or six weeks they have become full grown and spin thin cocoons of white silk among the leaves, in which they transform to dark-brown pupis. About three weeks later the moths emerge. Several native parasites and predaceous bugs prey TT -lie r,,, , i. -1 ., /E^ ,. upon the caterpillars, but Fig. 416. — The brown-tail moth (E^iprochs / '■ . ' chrysorrh(Fa Linn.): male above, female do not seem materially to below— natural size. reduce their numbers. In Europe there are several parasites which prey on all stages of the insect and which the State of Massachusetts with the 492 INSECT PESTS OF FARM, GARDEN AND ORCHARD cooperation of the U. S. Bureau ot Entomology is introducing in hope that they may ultimately be as effective in this country against both the brown-tail and gipsy moths. The most effective natural check of the brown-tail cat- erpillar is a fungous disease which often completely destroys large col- onies, both in the spring and fall. Control. — On fruit and shade trees the winter nests may be pruned off and burned in winter, thus pre- venting any injury the next spring, but this is impracticable on forest trees, which as a rule are not seri- ously injured. The repeated prun- ing often injures the trees, as it is difficult to cut all the nests with- out removing more of the new growth than is desirable. It is bet- ter, therefore, to spray the trees with arsenate of lead, 4 pounds to the barrel, as soon as the eggs hatch in late summer, and thus destroy the young larvae before they have spun their winter webs. Fig. 417. — Brown-tail moths as- sembled on electric light pole, Maiden, Mass., July 12, 1905. (After Kirkland.) The Gipsy Moth * History. — The Gipsy Moth has been known as a serious insect pest in Europe from the time of the earliest naturalists, the first authentic record being in 1662. It extends throughout the con- tinent of Europe, over much of Asia and into Northern Africa, but is chiefly injurious in Central and Eastern Europe. It fre- * Porihetria dispar Linn. Family Lipnridoe. See Forbush and Fernald, "The Gipsy Moth," Mass. State Board of Agr. (1892); L. O. Howard, Farmers' Bulletin 275, U. S. Dept. Agr. ; Annual Reports of the Mass. Super- intendent for the Suppression of the Gypsy and Brown-tail Moths; E. D. Sanderson, Bulletin 1,36, N. H. Agr. Exp. Sta.; Rogers and Burgess, IBuUetin 87, Bureau of Entomology, U. S. Dept. Agr., containing bibliography, and A. F. Burgess, Bulletin 204, U. S, Dept. Agr. INSECTS INJURIOUS TO ORCHARD FRUITS 493 quently does serious injury there by defoliating large areas of forest and more ferquently fruit and shade trees, but its ravages cease in two or three seasons, not to occur again for several years, like those of many of our native insects, such as the forest tent caterpillar and tussock moth. In 1868 the insect was brought to this country by Professor Leopold Trouvelot at Medford, Mass., in his experiments in silk producing. Escaping from him into the neighboring woodland, the insect increased gradually for several years before being noticed, but in 1890 had become such a serious Fig. 418. — Gipsy moth caterpillars— natural size. (After W. E. Britton.) pest throughout this and neighboring towns that the State of Massachusetts commenced the arduous task of its extermination. At this time the insect occurred in some twenty towns. For the next ten years it was successfully combated by the Massachusetts authorities, and in 1898 it had spread to but three towns not infested in 1890 and in many places it had apparently been exter- minated. So slight was the injury that legislative appropriations were discontinued for four years, during which time the moth spread over four times the area previously occupied and became so abundant that State action was again necessary. From 1905 to 1910 it spread throughout eastern Massachusetts and southern New Hampshire and Maine, and was found in two or, three local- 494 INSECT PFSTS OF FARM. GARDEN AND ORCHARD ities in Connecticut.* Appropriations for its control have been increased until now the State of Massachusetts and the Federal Government are each appropriating $300,000 per annum and the total cost of combating it in New England must be con- siderably over a milHon dollars per year. As it is gradually spreading, there seems every reason to fear that it may ultimately invade other States. Life History and Description. — The eggs are laid in July and August, in a mass of 400 to 500, covered with yellowish hairs from the body of the female. The mass is an irregular ovalshape 1| by f inches, and is deposited on the bark of trees, but where abundant, on • fences, stones, build- / ings, etc. The eggs hatch about May 1, and each mass yields a swarm of young cat- erpillars, the bulk of which become full grown by midsummer. Fig. 419. — The gipsy moth (Porthetria dispar rpi - + 'll r Linn.) : male above; female below— natural size. -•■ ^® mature caterpniar (After Forbush and Fernald.) has a dusky or sooty- colored body. Along the back is a double row of five pairs of blue spots, followed by a row of six pairs of red spots, which readily distinguish this from any other common caterpillar. The full-grown caterpillar is about 3 inches long. Sometime in July or early August it spins a few threads of silk as a sup- port, sheds its skin and changes into a pupa, sometimes enclosed in a thin cocoon, but often hanging pendant from its attach- * Connecticut State authorities, in co-operation with the Federal author- ities, have exterminated the insect within that State. Fig. INSECTS INJURIOUS TO ORCHARD FRUITS 495 ment. Characteristic light reddish hairs are scattered over the pupa. The pupal stage lasts from ten days to two weeks, when the adult emerges. The moths emerge from the middle of July to late August. The male is brownish-yellow, varying to greenish-brown in color, the wings being marked with darker stripes, has a slender body and the wings expand about 1 1 inches. It flies by day with a pecuhar zig-zag flight. The female moth is nearly white with numerous small black markings, is heavy- bodied and sluggish. The wings expand about 2 inches, but fortunately the female is unable to use them for flight. Were it not for this the spread of the pest would have been much more rapid. After mating the moths Hve but a short time and do no damage. The pest is spread mostly in the caterpillar stage The young caterpillars drop down on fine silken threads and may alight on vehicles which transport them to non-infested areas. When just hatched, the caterpiflars have very long hairs, slightly expanded at the base, and these, with the silk which they spin out, serve to buoy them up in the air so that they may be carried for a considerable distance by a strong wind Where they occur in myriads on high trees, the little caterpillars may be carried by the wind for considerable distances, and this is one of the chief means of spread.* The egg masses may also be transported on merchandise or boxing, and the pest has undoubtedly become established in several localities in this way. A few cases of importation on nursery stock have been known The caterpillars will attack any of the fruit, shade or wood- land trees, and where they become excessively abundant will destroy all green vegetation of almost any kind. It is essentially a pest of forest trees, but where it occurs it defohates all of the common fruit trees. Coniferous trees are killed after being once stripped of their fohage, and deciduous trees usually die after four or five defohations. Recent experiments show that the young caterpillars when they hatch from the eggs are unable to feed on conifers, so that growths of soft wood may be protected by keep- ing all hard-wood trees cut out * See C. W Collins, Bulletin 273, U. S Dept. Agr. 496 INSECT PESTS OF FARM, GARDEN AND ORCHARD Control. — In the orchard the gypsy moth is readily controlled by painting the egg masses with creosote in winter and by spraying Fig. 420. — Egg masses of the gyp^y uiolli uix the trunk of an apple tree. the trees with arsenate of lead, 5 pounds per barrel, just as the eggs are hatching in the spring. Where this is practiced there is very Httle trouble in controlling it in orchards. Upon shade and forest trees the problem is much more difficult and the reader Fig. 421.— The Calosoma beetle (Calosomn sycophanta). Upper left eggs' lower left adult beetle feeding on gipsy moth caterpillar; upper' right' gipsy motli pupa? destroyed by calosoma larvs; center, calosoma larva' ventral view; right center, calosoma larva, dorsal view; lower right' calosoma pupa in cavity in ground. (From Howard and Fiske.) ' 497 498 INSECT PESTS OF FARM, GARDEN AND ORCHARD should consult the authors cited (footnote, p. 492) as to the best means and apparatus. Although the pest is still confined to New England, it is such a serious one and there is so much danger of its spread elsewhere, that fruit-growers should be on their guard against it and should submit suspected specimens to the nearest entomologist. Should it be found in any other States, no expense should be spared to exterminate it absolutely before it may become established. The Federal authorities, in addition to maintaining a rigid quarantine within the areas infested by the gipsy-moth and the brown-tail moth, have made very intensive biological studies of the insects, both in this country and in its native home in Europe and have impoi'ted from Europe many of its natural enemies, including diseases, hymenopterous parasites and pre- daceous insects which attack it. Most important among the latter and possibly the most important of the insect enemies, is the ground beetle Calosoma sycophanta L., which is shown in the accompanying illustration. It is hoped that the importation of a large number of different kinds of natural enemies will, in time, reduce these insects to the status of native pests which are occasionally somewhat injurious but which are, over a period of years, held in check by the natural means of control, and the progress of the work during the past few years makes it seem likely that this will be accomplished. Canker Worms * Since the early colonial days Canker Worms have been among the best-known insect pests of the apple orchard, but they are general feeders and attack several orchard and shade trees. According to Dr. W. E. Britton they " seem to have a preference for the fohage of apple, elm, chestnut, pear, oak, hickory, box-elder, and maple, in about the order named," and cherry and plum are recorded by others. The canker worms are among the most common of the "loopers" or ''measuring worms," and are the larvae of two nearly related species of moths, very similar in both appearance and habits. The larvae defoliate the * Family Geometridoe. See D. W. Coquillet, Circular 9, Div. Ent., U. S. Dept. Agr.; W. E. Britton, Biennial Report Conn.Agr. Exp. Sta., 1907- 08, p. 777; A. L. Quaintance, Bulletin 68, Part II, Bureau of Entomol- ogy, U. S. Dept. Agr. INSECTS INJURIOUS TO ORCHARD FRUITS 499 trees in early spring, particularly in old sod orchards which have not been cultivated or sprayed. The Spring Canker Worm * This species is so called from the fact that its eggs are laid in the early spring instead of in the fall, as are those of the other species. It occurs from Maine to Iowa and southward to Texas, and in Colorado and California, but has not been reported on the Atlantic Coast south of New Jersey according to Coc^uillet. It seems to be particularly injurious in the Mississippi Valley. The full-grown caterpillar is from three- quarters to one inch long, slender, and cyhndrical, and has no prolegs on the middle of the abdomen. The color varies from ash-gray to green or yellow, but the predominating color is dai'k greenish-oUve or blackish, marked with narrow pale lines down the back and a whitish stripe along each side. The wings of the male moths expand an inch, and are semi-trans- parent, brownish-gray, with three rather indistinct dark lines across the fore-wings. The females are wingless and at the first glance look much more like spiders than moths. They are about one-third inch long, of a dull brown or grayish color with a dark brown stripe down the middle of the back. Life History. — The moths emerge from the pupse in the ground in March and April and the females climb up the trunks of the trees, where they place their eggs in irregular masses of about fifty, under loose scales of bark, in cracks in the bark, in crotches of limbs, etc. The individual eggs are yellowish-green, turning quite Fig. 422. — Canker worms dropping from foliage in characteristic attitudes. (After Bailey.) dark just before the larvas hatch, of an oval shape, and about one-thirty-fifth inch long. The eggs hatch in about a month and the young caterpillars commence to feed on the leaves just as they * Paleacrita vernata Peck. Family Geometridoe. 500, INSECT PESTS OF FARM, GARDEN AND ORCHARD are expanding, at first eating small holes through them, but later Fig. 423. — The spring canker worm (Paleacrita vernata): a, male moth; h, female moth — both natural size; c, joints of female antenna; d, joint of female abdomen; e, ovipositor — en- larged. (After Riley.) devouring all but the midribs. The young of dropping from the trees and hangin Fig. 424. — The spring can- ker worm {Paleacrita-ver- nata): a, larva — natural size; b, eggs — natural size and enlarged ; c, side view of segment of larva ; d , dor- sal view of same — both enlarged. (From Riley. caterpillars have a habit g suspended on strands Fig. 425. — The female moths of the spring canker worm — twice natural size, and pupae — three times natural size. (After Quaintance, U. S. Dept. Agr.) of silk. In four or five weeks they have become full grown and enter the soil to a depth of 2 to 5 inches, where they hollow out earthen cells, which they line with a little silk and in them change to pupse, in which stage the sum- mer and winter is passed. The pupse is Fig. 426. — Eggs of spring 'canker worm — twice natural size. (After W. E. Britton.) INSECTS INJURIOUS TO ORCHARD FRUITS 501 nearly one-third inch long, light brown in color, somewhat pitted, and the male pupa bears a simple spine at the tip of the abdomen. The Fall Canker Worm * The Fall Canker Worm seems to be the more common form in New England according to Dr. Britton and is a more northern species according to Coquillet, occurring through the North- Central States and in Colorado and northern California. As its name indicates, it differs in life history in that the moths emerge in November and December, "often occurring in great numbers on foggy days during a thaw after the ground has been frozen." They are most numerous about the middle of November in Con- necticut, although Dr. Britton states that when the ground freezes in early fall and does not thaw, many of the adults do not emerge until March, when the hfe history would be identical with the last species. The eggs are laid in clusters of about 100, arranged in rows, each egg fastened on end, and are laid on the bark of the smaller bran- ches or on the trunk. The egg i s brownish-gray, rather darker than that of the spring 427. — The fall canker worm {Also- phila pometriaa) : a, b, agg; c, d, side and dorsal views of larval segment — enlarged; e, egg mass; /, larva; gf, fe- male pupa — natural size; h, anal tub- ercle — enlarged. (From Riley.) species, and is shaped like a flower-pot, the outer end being marked with a dark spot in the centre and a dark ring near the margin. The eggs hatch in late April and early May in Connecticut. The larvae are very similar in general appearance to those of the spring canker worm, but may be easily distinguished by having two pairs of prolegs on the middle of the abdomen. The pupa is sim- ilar to that of the other species, but is somewhat stouter and the spine at the tip of the abdomen of the male pupa is always forked. The cocoon is much tougher, contains more silk, and is therefore less easily crushed. The male moth is sHghtly larger than that of the other species, with longer antennae, and the wings are firmer, less transparent and darker in color. The fore-wings are crossed by two whitish bands, the outer one being indented on the front * Alsophila pometaria Harris. Family Geometridoe. 502 INSECT PESTS OF FARM, GARDEN AND ORCHARD margin so that it forms a distinct spot, and this outer band is seen on the hind-wings, though it is less distinct. The females are a uniform, ash-gray without markings, and with longer antennae than those of the other species, the segments of which are about as broad as long, and are bare of hairs. Control. — In old sod orchards where the pest is always worst, thorough cultivation will largely destroy the pupse during the sum- fii mer. The caterpillars may be quickly de- ' -] stroyed by spraying with arsenate of lead, i 3 pounds per barrel. The first spray- ing should be applied as soon as the foliage is fairly expanded and before the trees bloom, and the second should be given as soon as the blossoms drop. The first is the more important and one thorough spraying will usually suffice, as the young caterpillars are much more easily killed. Where for any reason spray- mg is not feasible, the females may be prevented from ascending the trees by encircling the trunks with bands of tangle- foot or someother sticky substance which they cannot cross. These bands should be applied in early October and late March, according to the species preva- lent. The tanglefoot may be applied directly to the bark of the tree, making a band two inches wide by one-quarter inch thick. Printer's ink, bodlime, and caterpillar-lime are often used, but should not be placed on the bark. A narrow band of cotton batting should be run around the tree and cov- ered with a strip of building paper 4 to 6 inches wide, on the center of which the sticky band should be placed, thus preventing any injury to the bark by the material. Where spraying and cul- tivation are customary canker worms rarely become troublesome, but they are likely to be the worst insect pest of street-trees and wood-lots in the Middle-west. Fig. 428.— Wingless fe- male moth and egg mass, and winged male moth of the fall canker worm — twice natural size. ( A f t e r W. E. Britton.) INSECTS INJURIOUS TO ORCHARD FRUITS 503 The Evergreen Bagworm * The Bagworm is more frequently considered as a shade-tree pest than as an orchard enemy. At the same time its possi- bihties for injury in the orchard are of great importance. We have seen apple orchards with many trees killed in a period of two years and in one instance in Kansas a ninety-acre orchard Fig. 429. -Canker worm innili- ; l^ ■j,^^^^^ ^^^^^ .^ for budmoth.leaf-roller.tent caterpillars, canker -worms.plum curcul io, and scab. Where apple red bugs are troublesome add nicotine CodJInVlnoth ^ suJphate(Vlpt.toevery50?als.ofspray).Thiss:ives , IX^ also further protection against aphids. '^SV 'yvi^ Where bud-moth ana leaf-roller are especially ^v^^yKu^ troublesome use 3 lbs. of the powdered arsenate (or 6 lbs. of the paste form) to every 50 g-als.of spray and apply wAen the blojsom duds are first in evidence. III. SECOND SUMMER SPRAY Use same spray as in II just after the petals have fallen but before the calyx lobes have closed. This spray is for same pests as in 11 and is the most important spray {or scab and COD LING WyTWSpec2al care should be taken to drive tlte poison into the open calyx cups because the majority of the codling- moth larv« cf the fir^t. broodwill enterthe apples throughthe calyx end If apple red bug's are still troublesoiTie add Injury~~^"^P^ J nicotine sulphate as in II. by second ^•'—^ i; broodofcodlinsmoth. IV. THIRD SUMMER SPRAY -- 4,--.^ Use same spray as inll three or four w^eeks after the petab iS'^^w'^'ay have fallen for same pests as before and for leaf-spot . -« '■■ — V. FOURTH SUMMER SPRAY Use same spray as in 11, eig-ht or nine -weeks after the petals have fallen, for second brood of the cod- liny moth and for scab; or use BordeauLX mix- ture (3" 3 "50) in place of lime-sulphur.espec- ially If blotch and bitter- rot are present for Ai" '"/'<" eerAflHKRS'BLrj.Z.ETll\r'i-S£,U^DA. Effectofplumcup culioorvapplcsat^ pickirig- time. Fig, 442. — Apple spraying chart. Bureau of Entomology, U. S. Dept. Agr. 513 CHAPTER XXV INSECTS INJURIOUS TO THE APPLE AND PEAR The Woolly Apple-aphis * The Woolly Aphis is one of the most destructive pests of young apple orchards, and as it works mostly upon the roots it often escapes detection until the tree is badly injured or killed. Fig. 443. — The woolly apple-aphis {Eriosoma lanigera Hausm.): a, agamic female; 6, young nymph; c, last stage of nymph of winged aphis; d, winged agamic female with enlarged antenna above — all greatly enlarged and waxy excretion removed. (After Marlatt, U. S. Dept. Agr.) The aphids will be found clustered in bluish-white, cottony masses, looking like patches of mold, on the smaller twigs, par- ticularly water-sprouts, and around wounds or scars on the trunk * Eriosoma lanigera Hausmann. Family Aphididoe. See C. L. Mar- la'tt, Circular 20, Div. Ent., U. S. Dept. Agr.; R. I. Smith, Bulletin 23, Ga. State Board of Ent.; Gillette and Taylor, Bulletin 134, Colo. Agr. Exp. Sta., p. 4- C. P. Gillette, Journal of Economic Entomology, Vol. I, p. 306; A. C. Baker, Report 101, U. S. Dept. Agr., and B. R. Leach, Bulletin 730, U. S. Dept. Agr. 614 INSECTS INJURIOUS TO THE APPLE AND PEAR 515 or limbs. Their presence in these places is always an indication that others are feeding upon the roots, where they cause gall-like swelHngs, so that the roots soon become a mass of knots and die in a year or two if the injury continues. When badly attacked a tree becomes sickly, the foliage turns yellow, and if not killed outright by the aphids, it falls an easy prey to borers and other pests. Injury seems to be worse on hght soils and not so severe on heavy soils. Whether the insect is a native or a European species is a matter of dispute. In Europe it is called the "Amer- ican bhght," and was described from Germany in 1801. It has now become distributed all over the world on nursery stock, which forms the principal means of its dissemination. Fig. 444. — The woolly apple-aphis: at left, apterous viviparous female; 10, fall migrant; 11, over-winter young. (After Gillette and Taylor.) Life History. — On infested trees aphids will be found in all stages of growth on the roots in early spring. On the trunk, under bits of bark or under the dead bodies of those killed the previous fall, will be found numerous small aphids which have hibernated there, though in the North these may be killed out during severe winters. As the buds begin to open, the aphids on the trunk locate on tender new bark and commence to feed, and many migrate from the roots t5 the top at about the same time They are not usuallj^ detected until they have multipHed sufficiently to make small white patches, on the bark or leaves, which look hke mold. During the spring and summer all are wing- less females, not over one-tenth inch long, of a reddish-brown 516 INSECT PESTS OF FARM, GARDEN AND ORCHARD color and covered with a white, waxy secretion, given off in threads from the abdomen so as to form a cottony mass over the colony. These females produce from 2 to 20 young per day, which become full grown in from eight to twenty days according to Alwood,* 100 or more probably being produced in two weeks. FiQ. 445. — The woolly apple-aphis: at left, colonies on twig and in scar on an apple limb; at right, crown and root of young apple tree, showing characteristic swellings produced by the root aphids. (After Alwood.) Reproduction continues on both tops and roots except as checked by the cold of winter, the aphids becoming most abundant in midsummer. Early in the fall a generation of winged aphids appears, which migrates to other trees. They are about one- twelfth inch long and have a wing expanse of one-quarter inch. They appear to be black, but the abdomen is really a dark yel- lowish or rusty brown color when closely examined, and bears more or less of the waxy secretion on the tip. Each of these winged females gives birth to from four to six wingless males and * Bulletin 45, Va. Crop Pest Commission, p. 12, Special Bulletin, Va. Agr. Exp. Sta. Fig. 446. — ^Woolly apple-aphids on stem of seedling tree and swellings made on roots slightly enlarged. (After Rumsey and Brooks.) 517 518 INSECT PESTS OF FARM, GARDEN AND ORCHARD females, which are deposited on the trunk of the tree. The sexes are wingless, much smaller than the summer forms, and are without beaks, so that they take no food. The female is a brown-ochre color, and the male dark green or greenish- brown and smaller, as shown in Fig. 448. They become full grown in about eight days, when they mate and the female then Fig. 447. — Sexual female of the woolly apple-aphis, showing egg before and after extrusion — greatly enlarged. (After Alwood.) lays a single large black egg, which is deposited in the crevices of the bark on the lower part of the trunk. These eggs hatch in the spring and give rise to new colonies. As they multiply large galls are produced on the roots, the tissue probably being poisoned by the mouth-parts of the insects. As a result the roots soon die and the aphids then migrate to the growing roots, so that their absence on the worst knotted roots does not indicate that they have forsaken the tree but that they are on younger roots. Control. — Nurserymen commonly apply a liberal amount of tobacco dust in trenches along the rows, which kills the aphids and acts as a repellant, as well as being worth haK its cost as a fertilizer. This is probably the best practice in the nursery unless the aphids become abundant when more vigorous treatment should be used, but tobacco has not always proven a satisfactory treatment for orchard trees though used with apparent success INSECTS INJURIOUS TO THE APPLE AND PEAR 519 in some instances. The aphids may be destroyed on the foHage by spraying with 7 per cent kerosene emulsion, miscible oils diluted 30 to 40 times, whale-oil soap, 1 pound to 6 gallons, or tobacco extracts, '' black leaf -40" being used 1 part in 700 of water. Whatever insecticide is used must be applied in a strong spray so as to wet thoroughly and penetrate the waxy covering of the aphids. A winter spray of lime-sulphur wash destroys the hiber- nating aphids on the trunk, and doubtless kerosene emulsion or miscible oils applied in early spring, as for the San Jose scale, would be as effective, though the Ume-sulphur would probably also de- stroy some of the eggs. The trunks of trees known to be infested may be Fig. 448.— Sexual female and male of the banded with tanglefoot wooHy apple-aphis — greatly enlarged. . ., . , , (After Alwood.) or similar sticky mater- ials as described for canker worms (p. 502) to prevent the aphids from migrating from the roots to the top. Where the aphids are abundant on the roots, the earth should be removed for 6 or 8 inches deep over the affected roots and lime-sulphur solution, diluted about one to eight, applied in quantities sufficient to wet the soil thoroughly about the roots. Other solutions tried for soil treatment have given less success than this. Some success has been reported by Leach from the use of carbon disulphide in water solution, one ounce to four gallons, applied about the roots with a power sprayer. Sodium cyanide solution, applied in the same way also gave fairly good results. With any of these methods there is the disadvantage that they require large quantities of water to be transported to the orchard and all are somewhat expensive. Liberal fertilization, to enable the tree to do well in spite of the presence of the aphids is probably more practical for most growing conditions. 520 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Round-headed Apple-tree Borer * The young apple orchard must be given frequent inspection to detect the work of the round-headed borers, for if they become estabhshed in the young trees it is difficult to kill them and they soon girdle the trunks. They are most injurious to apple and quince, less so to pear, and also infest wild thornapple trees and mountain ash. The species occurs generally east of the Rocky Mountains, but is not commonly injurious in the Gulf States. The presence of the borers may be detected by the retarded growth Fig. 449. — The round-headed apple-tree borer (Saperda Candida Feb.) larvse, adults, and exit holes — natural size. (After Rumsey and Brooks.) of the trees, with a yellowing of the fohage, and the sawdust like castings which the larvse throw out from the entrances of their burrows, accompanied by a discoloration of the bark over the new burrows, and in early spring there is often a sUght exudation of sap. Injury is most severe in neglected orchards, where grass and weeds are allowed to grow about the bases of the trees, as the beetle, which flies at night, seeks the concealment of the rank vegetation during the day. The parent beetle is a handsome * Saperda Candida Fab. Family Cerambycidoe. See E. P. Felt, Bulletin 74, N. Y. State Museum, p. 23, which gives full bibliography to 1902, and F. E. Brooks, Farmers' Bulletin 675, U. S. Dept. Agr. INSECTS INJURIOUS TO THE APPLE AND PEAR 521 insect about three-quarters inch long. The antennae and legs are gray, the head and under surface of the body silvery white and the upper surface is light brown with two longitudinal white stripes. Life History. — The beetles emerge from late May to the middle of July and the females soon commence to deposit their eggs. The female eats out a little slit in the bark, in which the egg is inserted and often pushed under the bark and then covered with a gummy substance. It is a pale rust-brown color, about one-third inch long, of a broad oval shape, and usually concealed on young trees. The egg hatches in two or three weeks. The young larvsB tunnel just under the bark on the sap-wood, usually working down Fig. 450. — Work of the round-headed apple-tree borer: a, puncture in which egg is laid; h, same in section; e, hole from which beetle has emerged; /, same in section; g, pupa in its cell. (After Riley. — ) toward the base of the tree, the bark over these burrows often cracking the next spring, and the fine castings and borings sifting out. At the beginning of the second year the larva is about five-eighths inch long. The larva continues in the sap-wood during the second season, and it is at this time the most serious damage is done, for where several occur in a tree they almost girdle it. The next season they penetrate into the heart-wood, and several of them will fairly riddle a small tree with their cylindrical burrows. The full-grown larva continues this burrow out into the bark, often cutting clear across a tree. The upper part of the burrows are stuffed with fine borings and the lower 522 INSECT PESTS OF FARM, GARDEN AND ORCHARD part with long wood fibres. The full-grown larva is a Ught yellowish, cylindrical grub, about three-quarters inch long. The head is small, legs are lacking, and the body tapers gradually from the thorax backward, the segments being quite constricted. The third spring the larvae transform to pupae and about three weeks later the adult beetles emerge through large round holes. This habit is varied, according to Brooks, in some localities the majority of the beetles emerge in two years from the time Fig. 451. — Young apple tree protected from borers by a wire screen pro- tector. Photo by W. E. Rumsey. of hatching in place of in three, as is generally the case in the northern range of the insect. Control. — The females may be prevented from laying their eggs by wrapping the trunks with wire netting, building paper, or wood veneer. If non-rusting wire netting is used it may be left on and will also protect the trees from mice and rabbits. The paper or wood wrappings should be applied about May 1st, and removed in late summer. They should be tied to the tree tightly just below the crotch and should extend an inch or two into the soil below. The wire netting should be held out from the INSECTS INJURIOUS TO THE APPLE AND PEAR 523 trunk of the tree by a layer of cotton batting under it at the upper end. Various washes have been used to repel the beetles. Thick whale-oil or caustic soft-soap to which a pint of crude carboUc acid is added to every 10 gallons is often used and should be painted over the trunk so as to form a thick coating. Others recommend a thick coating of white- wash to which a Httle Portland cement is added to make it more adhesive. These should be applied by the middle of May and as often as need be to keep the trunk covered until late summer. Asphaltum, melted and painted onto the trunks, gives better results than any of the other materials of this nature, accord- ing to results secured in West Vir- ginia, but none of the treatments seems to be entirely satisfactory. If the trees are gone over every fall and spring, the egg scars and burrows of the young larvae may be detected and these may be cut out while still in the sap-wood, without much injury to the tree. When the borers get into the heart-wood it is almost impossible to dig them out without doing more injury to the tree, but they may sometimes be destroyed by injecting carbon bisulfide into the burrows and plugging the aperture with putty or clay. Where a tree has been nearly or quite girdled, it may sometimes be saved by bridge- grafting. Orchards kept free of grass and weeds and trees with smooth healthy bark are much less affected. Fig 452.— Young tree painted -P, , . , 1,1,1 with asphaltum to keep out Brooks reports, also, that the beetles borers. Photo by W.E.Rumsey. 524 INSECT PESTS OF FARM, GARDEN AND ORCHARD may be poisoned by arsenicals; if so, the codling moth spray prob- ably is responsible for smaller numbers of borers being found in sprayed orchards than in neglected ones. The Flat-headed Apple-tree Borer * This species is more abundant than the preceding, but does less damage. It prefers trees which have been weakened or are diseased, and attacks almost all of the common orchard trees as well as numerous shade and forest trees, so that it is every- where common. The species is found from southern Can- ada to Mexico. The larvae live just beneath the bark, where they hollow out broad flat Fig. 453.-Thr7at-headed'appIe-tree channels which extend sHghtly borer (Chrysobothris femorata Fab.) : into the sap-WOod. The infest- a, larva; b, beetle; c, head of male; ,. , i j^ ^ i i .i d, pupa— twice natural size. (After ation may be detected by the Chittenden, U. S. Dept. Agr.) discoloration of the bark. Where abundant they will often completely girdle young trees, thus causing their death, and they are frequently found abundant under the loosening bark of the dying hmbs of large trees, as they infest not only the trunks, but the lower limbs. The adult beetle is about one-half inch long, dull metallic brown above, and the wing-covers taper sharply at the tip, somewhat Hke a click beetle. The wing-covers are ornamented as shown in the figure, and beneath them, as seen when in flight, the body is a bright metallic greenish-blue. The male is smaller and the head is green. The beetles are active during the heat of the day and may often be found on logs or injured trees. Life History. — The beetles emerge from the middle of May until mid-summer. The eggs are deposited in crevices of the bark, several often being laid together. The eggs are yellowish, irreg- ularly ribbed and about one-fiftieth inch long. The species receives its name from the shape of the larva, the thorax of which is very broadly expanded, so that it looks like the head, which is very small and ahnost concealed by it. The abdomen is much smaller and the whole body is flattened. The larva is about * Chrysobothris femorata Fab. Family Buprestidae. See F. E. Brooks, Farmers' Bulletin 1065, U. S. Dept. Agr. INSECTS INJURIOUS TO THE APPLE AND PEAR 525 one inch long, and usually rests in the curved position shown in Fig. 453. The larva becomes full grown in a single year and in the South may pupate in November, but in the North does not pupate until the next spring, when it remains as a pupa about three weeks. The beetle emerges through an elliptical exit hole, in contrast to the round hole of the round-headed borer. Control. — As this beetle is everywhere present, injury may always be expected if trees are not kept in a healthy condition, but if the orchard is well cared for it seldom suffers much damage. The same measures for preventing oviposition as suggested for the previous species are advised, but the repellant washes must be applied higher on the trunks and should extend to the lower branches as high as can be reached. The Oyster-shell Scale * Not infrequently young apple and pear trees are encrusted and killed by the Oyster-shell Scale, as are young poplars and maples. It is probably our most com- mon scale insect, being al- most always found on apple trees, on which it works on the bark or the twigs and trunk, reproducing even on old trunks, where the scales will be found under the loose bark and are undoubtedly a factor in causing the bark to slough off. All of the common orchard trees are occasionally infested but rarely injured, as are also maple, poplar, horse-chest- nut, willow and lilac. Quaintance and Sasscer give a list of over 100 trees, shrubs, and plants upon which the scales have been found. The species is a cos- mopobtan one, having been d Fig. 45-4. — The oyster-shell scale (Lepid- osaphes ultni Linn.): a, female scales on twig; b, female scales from above; c, same from below showing eggs; d, male scale — enlarged. (After Howard.) * Lepidosaphes ulmi Linn. Family Coccidce. See Quaintance and Sasscer, Farmers' Bulletin 723, U S. Dept. Agr., and references there given. '526 INSECT PESTS OF FARM, GARDEN AND ORCHARD introduced into this country at an early date and now being found in every State, and occurs throughout the world, where the food- plants exist. The mature female scale is about one-eighth inch long, of a dark-brown color, sometimes almost blackish, and shaped some- what like an oyster-shell, as shown in Fig. 454. The male scale is much smaller, and with but one cast skin at the anterior end, as shown in the same figure. ^Life History. — If one of the female scales be turned over during the winter, numerous oval, white eggs will be found under it, with the shriveled body of the female insect tucked away Fig. 455.— Three common scale insects; o, oyster-shell scale; h, scurfy scale; c, San Jos6 scale. All natural size. (Photo by Rumsey.) at the anterior end. These eggs hatch a week or two after the apples blossom, producing small yellowish insects, which look like mites as they crawl over the bark, which they often give a yel- lowish tinge where very abundant. The young insect is of microscopic size. It settles down after a few hours' wandering and begins sucking the sap from the bark. In a day or two long, white waxy filaments exude from over the body, which soon mat down and form the protecting scale, to which the cast skins are added when the insect molts. The female loses her INSECTS INJURIOUS TO THE APPLE AND PEAR 527 legs, antennae, and eyes, after the first molt, and when full grown is an elongate, yellowish, jelly-like mass, being simply a "repro- ductive sack, with her sucking mouth parts, through which the food is taken, inserted in the tissues of the plant." The females become full grown in about eight to ten weeks, when they lay from 40 to 100 eggs and then die. In the North there is but one generation a year, but from the District of Columbia south- ward there is a partial or complete second generation. When the male insects are full grown they emerge from the scales as two-winged flies, fertilize the females and die at once. Control. — See below The Scurfy Scale * "The Scurfy Scale, while infesting a considerable number of plants (some 35 in number), is a less general feeder than the preceding spe- cies. It occurs prin- cipally upon ros- aceous plants, such as the apple, peach, pear, plum, cherry, etc., and also on currant and goose- berry among cultiv- ated plants, but seldom becomes so abundant as to cause particular in- j u r y or require specific treatment. ' ' It is especially com- mon on apple and Fig. 456. — The scurfy scale (Chionaspis furfura Fitch) : o, c, females, b, d, males — o, b, natural size, c, d, enlarged. (After Howard, U. S. Dept. Agr.) pear and less so on cherry and peach, though it has been observed as quite destructive to peach in the South, greatly stunting the trees, though none were actually killed. The female scale is a * Chionaspis furfura Fitch. Family Coccidce. See Quaintance and Sasscer, I.e. 528 INSECT PESTS OF FARM, GARDEN AND ORCHARD dirty-gray color, irregularly shaped as shown in Fig. 456, c The male scale is much smaller, elongate, snowy white, and with three distinct ridges. Fig. 456, d. It is an American insect, being common from Southern Canada to the Gulf States. The life history, as far as known, is practically identical with that of the last species. Control. — As the last two species are practically identical in habits, they may be controlled by the same methods. Where the trees are sprayed with lime-sulfur wash for the San Jose scale, there will be but little trouble with these scales, and where specific treatment is required for them experiments indicate that a thor- ough coating with the Mme-sulfur wash while the trees are dor- mant, preferably in the spring just before the buds open, is one of the most effective remedies. The wash does not seem to kill the eggs, but to kill the young soon after hatching, and has been used successfully on both fruit and shade trees, but if there be frequent rains in late spring, so that it is washed off, or if the scales are very thick, it is not always entirely effective, but yearly treatments will always prevent serious damage. Apple Plant-lice * Several species of aphids or plant-lice commonly infest the foliage of the apple, and less commonly that of the pear, and though they differ somewhat in appearance and habits they are sufficiently alike to be discussed together, as the same methods of control apply to all. The Apple-aphis f This is the common Apple-aphis of Europe, and was first noticed in this country late in the last century, when it spread to all parts of the country within a few years, probably being * See Sanderson, 13th Report, Del. Agr. Exp. Sta.; A. L. Quaintance, Circular 81, Bureau of Entomology, U. S. Dept. Agr.; Gillette and Taylor, Bulletin 133, Colo. Agr. Exp. Sta., Parrott, Hodgkiss and Lathrop, Bulletins 402, 415 and 431, N. Y. Agr. Expt. Station, Quaintance and Baker, Farmers' Bulletin 804, U. S. Dept. Agr., and Robert Matheson, Memoir 24, Cornell Agr. Expt. Station. t Aphis pomi DeG. Family Aphididoe. See above references, and J. B. Smith, Bulletin 143, N. J. Agr. Exp. Sta.; C. P. Gillette, Journal of Economic Entomology, Vol. I, p. 303, and H. E. Hodgkiss, Bulletin 461, N. Y. Agr. Expt. Station. INSECTS INJURIOUS TO THE APPLE AND PEAR 529 d istributed on nursery trees. Only young trees are usually much in- j ured by this and the following species of aphids, old trees rarely being injured, except that where the aphids are ex- cessively abundant they sometimes injure the young fruit, causing it to become stunted and misshapen. The foliage of young trees soon be- comes covered with the ver- min, which feed on the under surfaces of the leaves, caus- ing them to curl up and then drop. This curling of the foliage is more commonly caused by this species than any other, though the rosy apple-aphis has a similar ef- fect. The aphids secret the sweet honey-dew very pro- p^^ 457 _g^^ggg ^j^l^^^ppl^.^pt^ig^^p;^^^ fusely and so attract large -pomi. After Baker, U. S. Dept. of Agr. numbers of ants, which feed upon it. The ants are always found associated with them, and the presence of numerous ants on a tree Fig. 458. — The apple-aphis, winged viviparous female — greatly enlarged, is a good indication of aphids. The honey-dew soon covers badly 530 INSECT PESTS OF FARM, GARDEN AND ORCHARB infested foliage and upon it there grows a blackish fungus which gives the leaves a sooty appearance, often visible on the twigs after they drop, and a good indication of injury by this species. The full-grown wingless females are about one-twelfth inch long, and shaped as shown in Fig. 457. They are of a bright green color, though occasionally yellowish, and the tips of the ant- ennse, honey-tubes, and tail are black. The winged female is sHghtly longer and the wings expand about one-quarter inch, the head is deep oHve brown; the thorax is blackish, and there are three black spots on the lateral margin of the abdomen, but otherwise it is colored hke the wingless female. Fig. 459. — Nymphs of the apple-aphis, clustered on a leaf, showing developing wing-pads. Life History. — The minute, oval, shining black eggs are to be found on the twigs during the winter, especially at the crotches and around buds and scars. They hatch just before the leaf buds open and the young aphids become full grown in two or three weeks, all of them being wingless. During the next two or three weeks each of these females will give birth to from 50 to 100 young, a few of which develop wings. All of the aphids of this second generation are also females, which give birth to live young without the intervention of males, which do not appear until fall. Their young develop in a week or ten days and most of them become winged and migrate to other trees. The develop- ment and reproduction continues in this fashion throughout the summer, both winged and wingless females being found in most colonies, though the size and coloration differ in the various INSECTS INJURIOUS TO THE APPLE AND PEAR 531 generations. Those which are to become winged may be dis- tinguished after the third molt by the blackish wing-pads at the sides of the body. With the first frost of fall the young develop into true males and females. Both are wingless, the male being much the smaller, has long antennae, is yellowish or rusty-brown, and is very active, while the female is larger, moves more slowly and is lighter in color, but later becomes a very ' ^ 1 ^ if 1 \ ^ ^ \M m is^r i vri'\ ^r-X / f^'-*^ ' ■ f..-Jf:5^,i' w ^^^^Yif K ^^^i»-" is about the same size as the plum curculio, but more reddish- brown in color, the abdomen is more robust, and the wing-covers bear four prominent humps, the anterior being much larger than those on the plum curculio. The snout of the apple curculio is as long as the rest of the body and is held straight forward from the head, instead of hanging down as does the snout of the plum curcuHo. The work of the apple curcuho is also different in that after laying the egg in a small cavity in the fruit, on crescent-shaped mark is made around it. The apple curculio is a native species which breeds in wild haw, wild crab, and wild cherry, and has been reared in plum, quince and pear. "It has been reported from Connecticut and Ontario south to North Carolina and westward as far as New Mexico. It seems to have been more troublesome in Missouri, Illinois and other mid-western States than else- where," but has never done any- thing like the injury due to the plum curcuho and can hardly be regarded as a serious pest. Life History. — The beetles commence laying eggs in the punctures from the surface and in fruit SOOn after the blossoms drop section. (After C. S. Crandall.) , , . ^ • j r • j. ^ ' and contmue for a period of sixty days, an individual female laying about 65 eggs. The eggs hatch in about five days and the larvse feed on the flesh of the apple for about twenty days, when they transform to pupae within the fruit. A week later the beetles emerge, but feed very Httle during the late summer before they enter hibernation for the winter. most of them leaving the trees by the latter part of August. Fig. 499. — Work of the apple curcuho; a, a', c, c', feeding punctures from the surface and in section; b, b', egg INSECTS INJURIOUS TO THE APPLE AND PEAR 563 The larva is a footless, whitish grub a half inch long when full grown with a hump-backed appearance due to the enlargement of the anterior abdominal segments, which prevents the larva from straightening out. The beetles injure the fruit by puncturing it for feeding and for the deposition of eggs, causing it to become dimpled and gnarled as does the plum curculio, and the larvae feed within the fruit, mining the flesh, in which they undergo their complete development. Control. — Thickets of wild crab or hawthorn trees should be destroyed wherever near an orchard, for the beetles will breed in their fruit and then migrate to the orchard. Jarring as for the plum curculio may be practiced on young trees, and spraying as for that species will doubtless largely reduce the injury. Usually this insect is not sufficiently injurious to warrant special treatment where its native food-plants are not overabundant near the orchard. The Pear Leaf Blister-mite * The pear leaf blister-mite has long been known as a pest of pear foliage wherever the pear is grown, and has similarly affected apple fohage in Europe, but only in recent years has it become a. serious pest of apple fohage in New York, New England, Ontario and Pennsylvania. Just why it should suddenly become an apple pest after having occurred in this country for years without noticeably injuring it is a mystery, though dry seasons may possibly be accountable for it. The work of the mites is recognized by reddish bhsters forming on the young fohage, which later turn blackish and have a corky texture. Badly affected leaves drop, so that a tree is often largely defohated, and where the mites are abundant they attack the young fruit. The mites are not true insects, as they belong to the same class as the spiders, scorpions, and ticks. One of the more common larger mites is the red spider of greenhouses, which affects flower- ing plants, vegetable crops, and fruits of all sorts. These little bhster-mites are of microscopic size, only 1-100 to 1-200 inch in length, so that they can be seen only with a lens, and must be * Eriophyes pyri Pgst. Class Arachnida. Order Acarina. Family Eriophyida;, with which are associated several nearly related species with similar habits. See Parrott, Hodgkiss and Schoene, Bulletins 283 and 306, N. Y. Agr. Exp. Sta. 564 INSECT PESTS OF FARM, GARDEN AND ORCHARD examined with a compound microscope to distinguish the species. One is shown much magnified in Fig. 500. They are elongate, with two pairs of legs, and slender abdomens, composed of 50 to 80 small rings, frequently marked with rows of small tubercles and ornamented with a few hairs and bristles. Life History. — The mites spend the winter in the buds, and as warm weather approaches in the spring they become active and move toward the base of the growing bud scales and feed there. As the young leaves unfold the mites migrate to them. They burrow through the surface of the leaf and feed upon the succulent tissue within, setting up an irritation which soon results in reddish spots on the surface. Within these mines the eggs are laid, as many as 14 having been found in a single blister. The young hatch in about a week and burrow around in all Fig. 500. — The pear leaf blister-mite {Erio-phyes pyri Pgst.): highly magni- fied. (After Parrott.) directions, feeding on the tissues and juices. When full grown they leave the gall through small openings in the under surface and start new colonies which produce similar galls. They con- tinue to reproduce and migrate throughout the summer, and under favorable conditions become numerous enough to completely infest the new leaves as they appear. In the fall they leave the leaves to hibernate in the buds as already described. On pear the blisters are at first greenish pimples, which become reddish and later brilliant red blisters, and finally they become brown or black and the tissue corky. When numerous the galls coalesce, forming dark brown patches over the leaf, which often break open, particularly along the edges of the leaves. On the blossom ends of the fruit and on the stems they produce light-colored pimples, which do not seem to injure the fruit. On apple the blisters are less brilliantly colored than on pear, INSECTS INJURIOUS TO THE APPLE AND PEAR 565 and become a light brown or dark green color on the upper leaf surface and uniformly brown beneath, looking something like the work of the apple rust. The young fruit is sometimes attacked, on which small green pimples, which later make blister-like spots or pock marks, are made toward the blossom ends, but which do not seem to cause much damage. Fig. 5U1. — Old leaf cluster with galls of pear leaf blister-mite on apple fruit and leaves. (After Parrott, Hodgkiss and Schoene.) Control. — The mites may be controlled by spraying with 10 per cent kerosene emulsion, miscible oils, or lime-sulfur wash used the same as for the San Jose scale. Spraying should be done in October or November as soon as possible after a majority of the leaves have fallen, as many of the mites are still in the pubescence of the young wood, where they are more easily de- 566 INSECT PESTS OF FARM, GARDEN AND ORCHARD stroyed than when under the bud scales. In spring spray just as the buds begin to break and show the tips of the young leaves; spraying later than this will injure the foliage, and earlier spraying is not as effective. By using lime-sulfur in the spring, the usual treatment with Bordeaux mixture for diseases at that time is rendered unnecessary. Where infestation is serious both fall and spring sprayings should be given; otherwise the fall spraying is the better. The buds and new growth should be thoroughly drenched, while the rough bark of the trunk and old limbs may be neglected as far as the mites are concerned. Where pear trees are but sUghtly infested, the spread of the pest may often be prevented by simply pruning out and burning the infested twigs upon the first appearance of injury. The Pear Psylla * Where the pear psylla is abundant, pear growers have come to fear it next to the San Jose scale, and until recently owners Fig. 502. — ^The pear psylla (Psylla pyricola Foerst): adult, full-grown nympji and egg — all greatly enlarged in different proportions. (After Slinger- land.) in eastern New York became so discouraged in their attempt to control it that orchards were cut down. It is an old European pest and was first noted in Connecticut in 1832, since when it has spread southward to Maryland and Virginia and westward to Michigan and IlHnois, in which States it has done considerable injury. The psyllas are nearly related to the plant-hce and are * Psylla pyricola Foerst. Family Pstjllidce. See M. V. Slingerland, Bulletins 44 and 108, Cornell Univ. Agr. E.xp. Sta. ; C. L. Marlatt, Circular 7, Div. Ent., U. S. Dept. Agr. INSECTS INJURIOUS TO THE APPLE AND PEAR 567 sometimes called jumping plant-lice, on account of the habit of the adults of giving a quick jump and flying from the foliage when disturbed. Like the plant-lice they reproduce very rapidly and suck the juices from the foliage and fruit. Usually the first indication of the pest is the prescence of large quantities of honey- dew, secreted by the njmiphs, with which the foliage becomes covered, and which attracts numerous ants. When the psyllas are numerous the leaves and fruit become coated with this sticky substance and it even drops from them like rain and runs down the trunk. A blackish fungus grows on the honey-dew and is always a good indication of the presence of the psylla. Badly infested trees are so injured by loss of sap that they shed their leaves in midsummer, the lower ones being the first to turn yellow and drop. The young fruit also drops from badly infested trees, which make but httle growth, as the young shoots are often attacked and wither early in the season. The adult psylla is about one-tenth inch long, of a reddish- crimson color with brownish-black markings, bronzy eyes and dark wing-veins, looking very much hke a miniature cicada or dog-day harvest-fly. Life History. — The adults hibernate over winter in crevices of the bark and there lay their eggs late in April or early May on the twigs or around the buds. The egg is about one-eighteenth inch long, hardly perceptible without a lens, and orange-yellow in color. It is pear-shaped with the small end drawn out into a long thread, and the larger end is attached to the bark by a short stalk (Fig. 502). The later generations deposit the eggs on the leaves often in rows or bunches. The eggs hatch in two to three weeks and the young nymphs feed on the leaf petioles in the axils of the leaves and later on the leaves, young fruit and tender shoots, from which they suck the sap. The nymph is a peculiar-looking little bug, broadly oval, flattened, of a yellowish color, with crimson eyes, but later becomes reddish with black markings and conspicuous black wing-pads, as shown in Fig. 502. They move very slowly and are frequently quite covered by their own honey-dew. After molting some four or five times, they finally transform to adults in about a month. According to Slingerland there are four generations in New York and probably five in Maryland. 568 INSECT PESTS OF FARM, GARDEN AND ORCHARD Control. — As the adults hibernate over winter in the bark the treatment advised for the pear leaf blister-mite furnishes the best means of control for the psylla, and winter treatment is absolutely essential for its successful control. Otherwise, the best time to spray is in the spring just after the eggs have hatched and before the nymphs have secreted much honey-dew. If winter or spring spraying has been neglected, the trees should be thoroughly sprayed with "Black-leaf 40" one to 1000 with soap added. Spraying should be done after a shower, which will wash much of the honey-dew off, as the chief difficulty in sum- mer spraying is to reach the nymphs through the thick coating of honey-dew with which they are covered. Ob- viously the spray should be apphed with considerable pressure in a coarse spray. The Pear Thrips* The pear thrips has been known as an enemy of pears, plums, prunes, cherries and other plants in California since 1904 and within the last decade has been reported from New York, Pennsyl- vania, New Jersey and Mary- land. It feeds on fruits. Fig. 503. The Pear Thrips {Tmniothrips ^^^jg flowers and leaves and Pyn Daniel). — 1. — Adult. 2.— Eggs. ' . . 3.— First-stage larva. 4.— Full-grown causes mjury aggregatmg at larva. 5.— Pupa first stage 6.— Pupa, jg^st a milhon dollars an- last stage. 7. — bide view of head show- . ^ ,./• • mi ing mouth parts. All greatly enlarged, nually m Cahtornia. Ihe (After Fosterand Jones, I.e.) insect is not markedly dif- ferent, to the casual observer, from the several other species of thrips discussed elsewhere in this volume. Adults appear on the fruit buds early in the spring and lay their eggs on fruit and leaf * Tceniothrips pyri Daniel. Family Thripidoe. See Foster and Jones, Bulletin 173, U. S. Dept. of Agriculture. The Pear Thrips (Taemiothr. INSECTS INJURIOUS TO THE APPLE AND PEAR 569 stems and young fruit, feeding at the same time on growing parts of the plant. Injury by the adults is generally to the fruit buds before blossoming. The young forms feed on fohage and fruit and cause the defacement of fruit called fruit scab which greatly reduces the quality, especially of prunes which are the greatest sufferers. They remain inactive as fully grown njrmphs from early summer until the following spring when the adults again appear. Control. — Since the insect spends a large part of the year in the soil in immature stages thorough cultivation throughout the summer may be expected to destroy large numbers. Spraying has not given entire satisfaction, but distillate oil emulsions are largely used in Cahfornia. These are made by mixing 30 pounds fish oil soap, twenty gallons distillate oil and twelve gallons of hot water, by pumping them together under high pressure through a spray outfit into the tank. This is stock solution and should be diluted at the rate of one to twenty. To this should be added Black-leaf 40, about one-half pint to 100 gallons of the spray. This is applied at the time the buds are bursting and may be repeated after the petals fall. Spraying with thick whitewash gives some control but the first solution is preferred. Any spray- ing treatment should be supplemented by hberal fertihzation. The Pear Slug * Not infrequently the foliage of pear and cherry, and occasion- ally of plum trees turns brown in midsummer, which is found to be due to small, shmy, slug-hke larvse which have eaten off the surfaces of the leaves. The Pear Slug is a common pest throughout the country, having been known here for over a century. It is an old European pest and has become distributed to many of the British colonies in various parts of the world. The parent insect is a small saw-fly, about one-fifth inch long, glossy black, with four wings w^hich are iridescent, with a smoky band across the middle, and which are folded over the back when at rest. Life History. — The flies are abroad by the time the foliage is well out, by the middle of April in Maryland and late May or early June in New England. Like most of the saw-flies the female is * Caliroa cerasi Linnaeus. Family TenthredinidcB. See C. L. Marlatt, Circular 26, Div. Ent., U. S. Dept. Agr., and R. L. Webster, Bulletin 130, Iowa Agr. Expt. Station. 570 INSECT PESTS OF FARM, GARDEN AND ORCHARD furnished with a strong ovipositor with saw4ike teeth at the tip, with which she cuts a little blister-like cell beneath the upper surface of the leaf, in which the egg is deposited, as shown in Fig. 505. The egg hatches in about two weeks and the little larva makes its way out of the cell through a crescent-shaped cut. The young larva is at first nearly white, except the yellowish- brown head, but very soon a slimy or gluey olive-colored Hquid exudes from over the entire body, giving it the appearance of a min- ute slug, from which it gets its name. The head is now dark brown, ap- pearing almost black under the slime, and the body is also darker. The anterior segments are much swollen, con- cealing the head and the thoracic legs. The ab- domen is furnished with seven pairs of prolegs, the usual pair on the segment being Fig. 504. — ^The pear slug (Caliroa cerasi Lin naeus.): a, adult female saw-fly; b, larva with ] g^ g -{^ slime removed ; c, same in norma state ; d, leaves ' . with larvae natural size; o, 6, c, much enlarged, wantmg so that the tip (After Marlatt, U. S. Dept. Agr.)— ^f ^j^g abdomen 18 slightly elevated. The Httle slugs commence eating out small bits of the upper surface of the leaf, which they gradually enlarge un- til nearly the whole upper surface is denuded, leaving merely a net work of veins, held together by the brown epidermis of the lower surface, which is nearly intact. Leaves thus injured turn brown, die and drop, so that a tree will sometimes be nearly def- oliated, except for the new growth which starts out. The larvse grow rapidly, becoming full grown in about twenty-five days, when they are about one-half inch long. When full grown the larva molts for the fifth time and loses its olive-green slimy appearance, becoming a light orange-yellow color, clean and dry, with a light- colored head marked by only the small circular black eye-spots on the sides. INSECTS INJURIOUS TO THE APPLE AND PEAR 571 The larva now enters the ground for an inch or two, where it forms a small cell, which is moistened with saHva so that the walls become somewhat mipervious to water. In six or eight days it transforms to the pupa and in about two weeks after the larva entered the ground the adult fly digs its way out of the soil. Some of the larvae of each generation, and all of those of the last generation re- _ _ . ^^s^^^'^"^ main in the soil over winter and transform to pupae the next spring. ,y~- At Washington, D. C, the *' . / first generation of larvse ■|t';..' disappear by the end of ^^•'■' June and the second gene- ^.^ ration, which is probably ■sjsMmsfi-- ^^ , followed by a third gen- i^ -^^^ eration, is most abundant M in early July, when the •„,•„! • •„ , • j^ Fig. 505. — Illustrating method of oviposition prmcipal mjury is done. ^^^ emergence of the pear slug: a, cut- Farther north there are ting of cell beneath epidermis, showing the but two 0-PTiPr^tinn«! thp tip of the ovipositor; 6, the cell after the egg out two generations, tne has been deposited; c, same after escape of second appearing in the larva — all much enlarged. (After Mar- August. latt.U.S.Dept.Agr.) Control. — By spraying with any of the arsenicals when the work of the slugs is first noticed on the foliage they may be quickly destroyed. Whale-oil soap, or other soap, 1 pound to 4 gallons, will also destroy the larvae as a contact insecticide. Hellebore, air-slaked hme, or almost any finely divided dust, thoroughly dusted over the trees will also destroy most of the larvae, which are very readily killed. In gardens where water under pressure is available, the slugs may be washed off by a jet from a hose, as they are frequently washed off by heavy rains, and are much less injurious in wet seasons. The Tarnished Plant-bug * The tarnished plant-bug is one of the most common and troublesome plant-bugs throughout the country from Canada to * Lygus pratensis Linn. Family Capsidce. See Stedman, Bulletin 47, Missouri Agr. Exp. Sta., Crosby and Leonard, Bulletin 346, Cornell Univ. Agr. Expt. Station, and Leonard Haseman, Research Bulletin 29, Missouri Agr. Expt. Station. 572 INSECT PESTS OF FARM, GARDEN AND ORCHARD Mexico. Seemingly it is nearly omnivorous, as it attacks almost all of the common garden crops, small fruits, tender shoots of fruit trees and young nursery trees, many flowering plants, and most of our common weeds. It is rather more important as an enemy of pears than on any other crop, causing deformation of the fruit to some extent every year in some of the important pear growing regions. At the same time it is quite as common as a garden pest, attacking a great variety of garden crops. Injury on pears by a bug of very simi- lar appearance is re- ported in New York. The bug most prevalent there is called the False Tarnishe^d Plant bug {Lygus invitus Say). Injury by the tarnished plant-bugs to peach has been blamed for a disease known as peach stop- back. Both nymphs and adults injure the plants by sucking out the juices, and on many plants a Fig. 506.— The tarnished plant-bug {Lygus small black spot appears pratensis Linn.) a, b, cd, four stages of where the insect has been nymphs: e, adult bug — all about four times natural size. (After Forbes and Chittenden, feedmg, which causes a U. S. Dept. Agr.) deformation of the stem or leaf, as in the ''buttoning" of strawberries, or tends to "blight" the terminal as in the case of dahhas, potatoes, and similar crops. The adult is nearly one-quarter inch long, of a brassy-brown color, marked with black and yellow, and the thorax with red. The color and markings are quite variable. The nymphs feed upon the same plants as the adults and pass through four stages, shown in Fig. 506. The first stage is only one-twentieth inch long and yellowish or yellowish-green. The second stage is about twice as large, and similarly colored, except that there are two pairs of dark spots on the thorax and one on the middle of the third abdominal segment, which grow more distinct in the last two INSECTS INJURIOUS TO THE APPLE AND PEAR 573 stages. With the third stage the small wing pads become visible and in the fourth stage they extend halfway down the abdomen. Life History. — The adults hibernate over winter under any shelter available, such as the trash on affected fields, under leaves, boards, stones, etc., and emerge in early spring. The eggs are laid in Missouri in April. But little is known of the places of oviposition, except that Taylor * has shown that some- times apples are severely dimpled by the egg punctures. It is evident, therefore, that the eggs are inserted in the stems or leaves of the food-plants. The pale yellow egg is about one- thirtieth inch long, oval, elongate, and flared at the outer end, so as to be somewhat bottle-shaped. The first generation becomes full grown in about a month, after which all stages may be found feeding together until September or October. In southern Missouri Professor Stedman states that there are three generations while in northern Missouri only two, but the exact number has not been carefully determined. Control. — This is is an exceedingly difficult insect to control, owing to the large number of food-plants and the fact that the adult takes wing and flies off quickly upon the least disturbance. As it sucks its food, arsenical insecticides are of course useless, and some contact insecticide must be used with which the insect may be hit. The nymphs may be sprayed at any time, but to hit the adult bugs they must be sprayed in early morning, while still sluggish. Spraying will be profitable where the njonphs are abundant, but it is doubtful whether it will be found a satis- factory means of combating the adults. Ten per cent kerosene emulsion and tobacco extracts have been used successfully. Where they are abundant the adults may be collected in consider- able numbers by sweeping the foliage in early morning with a strong insect net and then dropping them into kerosene. Clean culture, including the destruction of all weeds, and such vegeta- tion or trash as may furnish hibernating quarters, is important, as it is observed that injury is' always worse where weeds have been allowed to multiply and the ground has been covered with weeds and trash. * See E. P. Taylor, Journal of Economic Entomologj', Vol. I, p. 370. 574 INSECT PESTS OF FARM, GARDEN AND ORCAHRD Haseman (1. c.) states that insecticides have been of little value in the control of the insect in nurseries and recommends that injury be prevented by destruction of the weeds which harbor it, particularly members of the Compositce of which the "Mare's tail" {Erigeron canadensis) is said to be the most important. CHAPTER XXVI. INSECTS INJURIOUS TO THE PEACH, PLUM AND CHERRY * The Peach-tree Borer f Wherever peaches are grown they are subject to the attacks of the ever-present borers, and if neglected will soon succumb to their injury. East of the Rocky Mountains the common peach- tree borer has been known since the earliest settlements, and it also occurs in Colorado and Oregon. It is a native insect which probably lived on wild cherry and wild plum, and is known to attack plum, prune, apricot and nectarine, though chiefly a peach pest. On the Pacific Coast a nearly related species, the California peach-tree borer, J does similar injury and has very similar habits. The lesser peach-tree borer § is commonly asso- ciated with the more common borer and has done considerable injury in western New York, Maryland, Virginia and Georgia. It occurs throughout the country and is doubtless commonly confused with the larger and more common species. Although it is quite different in its Ufe history and habits, the injury is very similar, and as it must be controlled by the same methods it need not be separately considered. The presence of the borers may be detected by the mass of gummy, gelatinous material, more or less mixed with soil, which exudes from the crowns of trees injured by them. The injury is done by the larvae feeding on the soft inner bark of the crown of the root, the adjacent roots and the base of the trunk. Often the larvae will completely girdle a tree and where a tree is infested * See J. B. Smith, BuUetin 235, N. J. Agr. Exp. Sta. t Sanninoidea exitiosa Say. Family Sesiidoe. See Quaintance, Yearbook U. S. Dept. Agr., 1905, p. 330; M. V. Slingerland, Bulletin 176, Cornell Univ. Agr. Exp. Sta.; H. N. Starnes, Bulletin 73, Geo. Agr. Exp. Sta. t Sanninoidea opalesceris Hy. Ed. See C. W. Woodworth, Bulletin 143, Cal. Agr. Exp. Sta. § Synanthedon pictipes G. & R. See A. A. Girault, Bulletin 68, Part IV, Bureau of Entomology, U. S. Dept. Agr., and J. L. lung. Bulletin 307, Ohio Agr. Expt. Station. 575 576 INSECT PESTS OF FARM, GARDEN AND ORCHARD by several borers, the foliage turns yellow and if not treated will soon die. Such a tree is much more susceptible to the attacks of bark beetles and diseases. Probably as many peach trees are lost from the work of borers as from any other one pest, with the possible exception of the San Jose scale. The adults are clear-winged moths which fly during the day and might be readily mistaken for wasps. The females are a deep steel-blue with a broad orange band across the abdomen. The fore-wings are opaque, covered by the bluish scales, and ^ • enlarged. (After Marlatt, U. S. Crotches of the limbs. Their Dept. Agr.) presence is indicated by small mounds of comminuted bark, as shown in Fig. 512, at a and h. Early in the spring, as the foliage is putting out, the larvae begin to leave their burrows and attack the tender shoots, boring into and down the pith, the galleries ranging from about one-third inch to 1| inches in length. The shoot thus injured soon wilts and dies, as shown in Fig. 513, at a. Many shoots may be attacked by a single larva, which is thus capable of doing considerable harm. There are two or three generations of larvae during the summer in * Anarsia lineatella Zell. Family Gelechiidoe. See W. T. Clarke, Bulletin 144, Cal. Agr. Exp. Sta.; C. L. Marlatt, Bulletin 10, n. s., Div. Ent., U. S. Dept. Agr.; A. L. Quaintance, Yearbook U. S. Dept. Agr., 1905, p. 344. INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 581 Fig. 512. — Peach twig-borer in winter quarters: a, twig, showing in crotch minute masses of chewed bark above larval chamber; h, same, much en- larged; c, larval cell enlarged; and d, larva very greatly enlarged. (After Marlatt, U. S. Dept. Agr.) the West, those of the second and third attacking the fruit, the later varieties being the worst injured. According to Professor C. V. Piper, the larva enters the peach at the stem end, usually bor- ing into the pit, the seed of which it seems to prefer, usually caus- ing the stone to split as the fruit ripens; or simply the flesh may be tunnelled, depending on whether or not the stone is hard when the fruit is attacked. In California, according to Clarke, the larva usually enters the fruit along the suture at the stem end, and excavates a chamber beneath the skin, which black- ens and shrivels somewhat, af- fording entrance to organisms of decay. In the ripe fruit the larvae frequently make their way to and around the stone, which, if split, may be entered and the seed feed upon. . . . Early in the fall, about September 1, in CaUfornia, the very young larvae from eggs of the last generation of moths construct their hibernation cells in the soft tissue of the crotches of limbs, where they remain un- til the following spring, thus spending some six months in this condition." — Quaintance. Control. — By spraying dur- ing the winter, or preferably after the buds have swollen in the spring with kerosene or distillate-oil emulsion, the oil is absorbed by the cast- mgs at the mouth of the burrows of the hibernating larvae, and thus penetrates the burrows and kills the larvae. Lime-sulfur wash Fia 513. — ^The peach twig-borer: a, new shoot of peach withering from attacks ot larvae; h, larva enlarged; c, pupa, enlarged, (After Marlatt, U. S. Dept. Agr.) 582 INSECT PESTS OF FARM, GARDEN AND ORCHARD applied from the time the buds commence to swell until the first blossoms, has also been widely and successfully used. The wash should be appHed as late as possible before blossoming. Recently Mr. E. P. Taylor has shown * that in western Colorado the larvse are very readily killed by arsenate of lead, 3 to 5 pounds per barrel, applied just as the buds are beginning to open. The arsenate of lead must contain no soluble arsenic, or it may burn the foliage. This treatment is given at the same season as the lime- sulfur wash and is much easier to prepare and apply. The Peach-tree Bark-beetle f The peach-tree bark-beetle is very similar in both appearance and habits to the fruit-tree bark-beetle, and may be readily confused with it. It is a native insect which attacks only peach, cherry and wild cherry, and so far has been injurious only in western New York, northern Ohio, and the Niagara district of Ontario, though it occurs from New Hampshire to North Carolina and west to Michigan. "When the beetles are present in large numbers their injury to the tree is quickly brought to the attention of the orchardist by the large amount of sap exuding from the trees through the many small borings made both in the trunk and Hmbs of the tree. . . . The adults or beetles produce the primary injury to healthy trees, the work of the larvse being secondary. The healthy trees, by repeated attacks of the adults, are reduced to a condition favorable to the formation of egg-burrows. When the beetles are ready to hibernate in the fall they fly to the healthy trees and form their hibernation cells. These latter are injurious to the trees, for through each cell there will be a tiny flow of sap during the following season." When the beetles emerge in the spring they bore into the bark of healthy trees and later leave them to form egg burrows in sickly trees. From these numerous burrows the sap issues in large quantities and in many cases forms large gummy masses around the trees. After three or four years of such injury the tree is so weakened that the beetles form their egg burrows beneath the bark and the larvae soon finish its * E. P. Taylor, Bulletin 119, Colo. Agr. Exp. Sta., p. 8. t PhloEotribus liminaris Harris. Family Scolytidoe. See H. F. Wilson, Bulletin 68, Part IX, Bureau of Entomology, U. S. Dept. Agr. INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 583 destruction. There are two generations a year, the summer brood appearing in the latter half of August and the other hibernating over winter. Control. — The same methods are advised as for the fruit-tree bark-beetle, which see. The Peach Lecanium * The presence of the "terrapin scale," as this species is often called, is usually indicated by the sooty appearance of the branches and foHage of affected trees. This is due to the fact that the scales excrete considerable honey-dew, which covers the bark and Fig. 514. — ^The peach lecanium or terrapin scale (Eulecanium nigrofasciatum Pergande): adults at left, natural size and much enlarged; young at right, and unfertihzed female at center — much enlarged. (After Howard, U. S. Dept. Agr.) leaves, and on which a sooty fungus propagates. It is a common species throughout the eastern United States and also attacks the apple, maple, sycamore, linden and birch, but is most injurious to peach and plum. The hibernating, partly grown, female scale found on the bark in winter, is about one-twelfth inch long, hemispherical, and of a reddish color mottled with radiating streaks of black, particularly about the margin. Sometimes * Euclecanium nigrofasciatum Pergande. Family Coccidoe. See J. G. Sanders, Circular 88, Bureau of Entomology, U. S. Dept. Agr.; A. L. Quain- tance. Yearbook U. S. Dept. Agr., 1905, p. 340; T. B. Symons and E. N. Cory, Bulletin 149, Md. Agr. Exp. Sta., and F. L. Simanton, Bulletin 351, U.S. Dept. Agr. 684 INSECT PESTS OF FARM, GARDEN AND ORCHARD these streaks coalesce and form a dark band around the center, while other individuals are occasionally entirely red or black. Frequently trees become badly encrusted with these scales, but rarely are they killed by them. The fruit on badly infested trees is, however, poorly developed, in- sipid, and covered with the sooty fungus so as to be almost unsaleable, and the trees are stunted and rendered more liable to the attack of other insects. Life History . — There is but one gen- eration a year. In the winter they are mostly nearly grown female scales. These mature early in the spring and deposit their eggs in a mass beneath the body, which forms the hard scale above them. In Missouri the eggs hatch about June 10th, and continue to hatch for a month. The male scales are much smaller than Fig. 515.— The Peach Lecanium— enlarged. (After the females, elongate, Simanton.) slightly convex, and greenish-white in color. Late in July the winged males appear and live about a week. The young female scales continue growth during the summer and hibernate when about two-thirds grown. Control. — Lime sulphur seems to be ineffective against this insect but orchards which are sprayed year after year with it INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 585 suffer less than unsprayed ones. The best treatment for general use is miscible oil spraying. The oils to be used at about one to 16 or 18 and applied in the spring after the buds swell but before they open. Two treatmenrs in successive years must be given to Fig. 516. — Distribution in the United States of the terrapin scale (Eulecan- ium nigrofasciatum) . (After Simanton, I.e.) get the full benefit and it is better, in infested regions, to make it an annual treatment. The Black Peach-aphis * The black peach-aphis is a native species which has been most injurious in the Middle Atlantic States, but has become widely distributed on nursery trees. It attacks the roots, tender shoots and foliage of the peach When occurring on the roots, trees are often seriously injured before its presence is suspected. Young trees are particularly affected, the injured trees having a yellowish sickly foliage. Usually, however, the presence of the aphids on the young shoots and leaves will be an indication of its inhab- iting the roots also. In the spring and early summer the aphids cluster on the tender shoots at the crotch of the tree and low down on the limbs and soon form a disgusting black mass over the young leaves, which are tightly curled up from the injury. 586 INSECT PESTS OF FARM, GARDEN AND ORCHARD On young trees in the nursery and on young orchard trees, this injury to the foliage is sometimes so severe as to kill or severely check the growth. Both winged and wingless aphids are found on the foUage, but only the wingless forms occur on the roots. Both forms are about one-twelfth inch long and shining deep brown or black in color when mature. The partly grown aphids, which form the larger part of most colonies, are reddish-yellow or amber colored. Life History. — The wingless aphids feed and reproduce upon the roots throughout the year, all being females and giving birth Fig. 517. — ^The black peach-aphis (Aphis persiccB-niger Er. Sm.): winged viviparous female; young female, first instar; apterous viviparous female — much enlarged. (After GUlette and Taylor.) to live young after the manner of the aphids. In the spring some of them migrate to the young foHage, often appearing on the tender twigs before the buds open. They multiply rapidly, and as a result of the hundreds of little beaks sucking out the juices the shoot soon withers, which causes the young to develop into winged aphids which migrate to other trees. Honey-dew is excreted very freely by the aphids, which are therefore attended by numerous ants which doubtless aid in their transportation from tree to tree and from the roots to the leaves and back. "During summer the aphids for the most part are to be found * Aphis persicce-niger Er. Sm. Family Aphididoe. See C. P. Gillette, Bulletin 133, Colo. Agr. Exp. Sta., p. 37; A. L. Quaintance, Journal of Eco- nomic Entomology, Vol. I, p. 308, Yearbook U. S. Dept. Agr., 1905, p. 342. INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 587 on the roots, though a few may be found on the foliage and the shoots in badly infested orchards at almost any time during the growing season . . . Light sandy soils are worst infested, though they have been found in abundance on stiff clay soils. " (Quain- tance, I.e.). Control. — The roots of young trees suspected of being affected should be carefully examined and if aphids are found they should be dipped in strong tobacco water. Nurserjmien prevent injury by making liberal appHcations of tobacco dust in the trench and along the rows. Tobacco dust may also be used against the aphids on the roots of orchard trees by removing the surface soil and applying a liberal dressing of the dust, which will be leached down on to the roots by the rains. It should be applied over the smaller roots. The treatment for the root forms has not been sufficiently studied to warrant any conclusions as to satisfactory methods, but the same as advised for the woolly apple- aphis (p. 518) are suggested. When the aphids appear on the young shoots in the spring they may be readily controlled if the trees are observed for their appearance, for they are very grega- rious, clustering on one shoot until it is well covered before spread- ing to the rest of a tree, and becoming abundant on it before spreading to others. Often the small infested shoots may simply be broken off and destroyed. The aphids may be killed by spraying them with tobacco extract. The Green Peach-aphis * This aphid is a European species which has long been known as a pest of peach foliage in this country, where it has become widely distributed. Considerable interest attaches to the species, as it furnishes a striking example of the summer migration of aphids to different food-plants, and a consequent difference in appearance in form and color. During the summer this species feeds upon various vegetables and succulent plants, and is so different in color and form that it has been well known not only as a separate species, but as belonging to a distinct genus. Con- cerning its injury to the peach, E. P. Taylor states: " The peach-growers of Western Colorado have suffered loss from it, from its heavy infestation of the leaves of the trees in the spring, 588 INSECT PESTS OF FARM, GARDEN AND ORCHARD causing them to curl and drop prematurely to the ground, and from the withering and subsequent dropping of the buds and forming peaches also infested by the aphids at this time. " Similar injury has been reported from Missouri, and doubtless occurs occasionally in other sections. Life History. — The winter is usually passed in the egg stage on the peach, plum, apricot, nectarine, cherry or other trees, though the wingless females sometimes persist on the summer food-plants where there is sufficient protection to enable them to endure the cold of winter, as in cabbage pits, or in the South. The small, oval, shining black eggs are deposited in the axils of the buds or in crevices of the bark. "The eggs hatch very early in the spring so that the young stem-mothers from them are often almost fully grown before the earHest peach or plum blos- soms open. About the time the buds begin to open on these trees, the stem-mothers are all of a deep pink color and begin to give birth to living young. These young instead of being pink Uke their mothers are pale yellowish-green throughout their lives, and usually there is a median and two lateral dark green stripes passing over the abdomen. Very few of this brood attain wings. The third generation become very largely winged and begin leaving the trees upon which they were born about the mid- dle of May in the peach-growing sections of the State (Colorado). By the middle of June these lice have almost completely left the trees and may be found establishing their colonies upon various succulent vegetables." The winged females which migrate from the peach are about one-twelfth inch long, with a wing expanse of one-third inch. They are a yellowish-green color with head, antennae, thoracic lobes, honey-tubes, a large spot on the centre of the abdomen, and small lateral spots in front of the honey-tubes are blackish. The wingless females during the summer are pale yellowish and lack the longitudinal green stripes on the abdomen. According to Taylor's observations the spring generations on peach become full grown in about two weeks and an individual aphid Kves about a month. In the fall * Myzus persicce Sulz. Family Aphididoe. (Syn. — Rhopalosiphum dianthi Schr.). See Gillette and Taylor, Bulletin 133, Colo. Agr. Exp. Sta., p. 32; C. P. Gillette, Journal of Economic Entomology, Vol. I, p. 359; E. P. Taylor, ibid., p. 83; F. H. Chittenden, Bulletin 2, Va. Truck Exp. Sta., p. 30. INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 589 winged females return to the peach and winter host-plants, and give birth to young which develop into wingless females which lay the winter eggs. The true males are winged and migrate from the summer food-plants. Control. — The trees affected should be sprayed about a week Fig. 518. — The green peach Aphis {Myzus persicce Sulz.) : 5, adult stem mother; 6, young of stem mother; 7, apterous viviparous female of second genera- tion; 8, spring migrant; 9, fall migrant; 10, egg-laying female; 11, eggs — all much enlarged. (After Gillette and Taylor.) before the buds open with tobacco extract. If the trees are sprayed with lime-sulfur for the twig-borer just before blossoming, it should kill most of the aphids. Tobacco extract may be used on the foliage of affected plants as necessary. 590 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Green Soldier Bug * The Green Soldier Bug has done serious injury to peaches in Ohio and West Virginia as well as other localities in recent years and is known as an important enemy of garden crops, particularly Lima beans. It " stings " the developing pods of the beans, sucks the sap from them and no beans develop. Its injury to peaches is done by sucking sap from the develop- ing fruits from the time they are half -grown until they ripen. The adult is one of our larger green stink-bugs of the common- stink-bug form and will be easily recognized from its name. The nymphs are darker in color, ranging from blackish to yellowish- green with black markings, depending upon the stage. The nymphs are more likely to be observed doing the damage than are the adults. This species is very similar to another southern form called the southern green plant-bugf, which injures fruits but is more important as a pest on truck crops. Control. — It is fortunate that this insect is held in check by climate and natural enemies since there are no artificial control measures available as yet. Hand picking, or jarring into cans of kerosene, might pay on a small scale in gardens. It appears that the insect may be expected to occur in injurious numbers only after mild winters and it is attacked by several parasites so its occurrence as a pest is only occasional. The Plum Gouger | This is a 'native beetle which breeds upon wild plums and is most injurious to native varieties. It is common throughout the Mississippi Valley, but seems to be most injurious westward and occurs in Colorado. The work of the beetles might be easily mistaken for that of the curcuHo (p. 505). The adult beetle is readily distinguished from the curcuUo, however, by lacking the humps on the wing-covers. * Nezara hilaris Say. See R. D. Whitmarsh, Bulletin 310, Ohio Expt. Station, and p. 236, Chapter XIII. t Nezara viridula L. See T. H. Jones, Bulletin 689, U. S. Dept. Agr., and J. R. Watson, Bulletin 134, Florida Expt. Sta., also page 630, Chapter XXVII. \ Coccotorus scutellaris Lee. Family Curculionidce. INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 591 It is about one-quarter inch long, with a snout half as long, the wing-covers are a leaden-gray color, finely spotted with black and brown, while the thorax and head are marked with ochreous yellow. Life History. — Like the cur- culio, the beetles hibernate over winter and appear in the spring as the trees blossom. At first they puncture the calyx and feed on the ovary of the flower, com- pletely destroying it for fruit pro- duction, and then puncture the growing plums, both for food and for egg-laying. In feeding on the plums the adults gouge out small round holes, from which gum exudes. Like the curculios, they have the habit of feigning death and dropping to the ground when disturbed. The eggs are laid while the pit of the plum is still soft. The female beetle drills a small hole which is larger below, in the plum, and in it deposits a small yellowish-white egg, whose outer end lies flush with the surface of the plum. As soon as the larva hatches it eats its way into the pit, feeding upoji the meat of the seed until full grown. It then eats a hole through the outside of the pit so that the adult beetle may escape, and then transforms to a pupa. The larva is very similar to that of the curculio, but is a milky white rather than a glossy white and lacks the reddish tinge on the lower surface. Affected plums do not drop as when injured by the curcuHo. The pupal stage is passed in the pit of the plum and the adult beetle emerges through the hole cut for it by the larva. The beetles emerge a little before the plums ripen and often practically destroy them, as fruit badly punctured becomes gnarly and worthless. The beetles feed on the plums a short time and then seek hibernating quarters for the winter. Control. — Control measures have not been thoroughly tested, but where the beetles are abundant it would be well to try spray- ing with arsenate of lead as advised for the curculio. Fig. 519. — The plum gouger (Cocco- torus scutellaris Lee): a, plum stone showing exit hole of larva; b, adult; c, side view of head of beetle — enlarged. (After Riley and Howard, U. S. Dept. Agr.) 592 INSECT PESTS OF FARM, GARDEN AND ORCHARD Plum Aphids Three species of aphids are common on the plum foliage in spring and fall, and often do serious damage by curling up the foliage in the spring and causing it to drop prematurely, thus checking the growth of the tree and preventing proper fruiting. The life histories of the three species are very similar in that the eggs are laid upon the plum in the fall, upon which two or three generations develop in the spring, but in early summer they migrate to other food-plants, from which they return to the plum in the fall. The life history is much the same as that of the apple-aphis, and green peach-aphis, and need not be rehearsed in detail. The Mealy Plum-louse * This is a Ught-green species which is covered by a bluish- white mealy powder. It has a long narrow body, one-tenth inch long. Fig. 520. — ^The mealy plum louse (Hyalopterus arundinis Fab.) : a, young nymph; h, last stage of nymph of winged form; c, winged viviparous female — all much enlarged. (After Lowe.) marked with three longitudinal stripes of a darker green. The honey-tubes are short, thick, and slightly constricted at the base. The winged female is similar in coloration except that the abdomen bears several transverse triangular marks of darker green. In June the winged females migrate to certain grasses upon which the aphids reproduce during the summer, though small colonies * Hyalopterus arundinis Fab. Family Aphididoe. W. D. Hunter in Bulletin 60, Iowa Agr. Exp. Sta., p. 92, states that Aphis prunifolioe Fitch is probably the same species. Certainly H. arundinis and pruni, Aphis pruni and prunifolice, seem to have been applied to the same species in the economic literature in America. See Lowe, V. L., Bulletin 139, N. Y. Agr. Exp. Sta.. p. 657, and W. M. Davidson, Bulletin 774, U. S. Dept. Agr. INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 593 are to be found on the plum throughout the summer. In the fall they return to the plum, where the winter eggs are laid. This species is known to occur in Germany, England, Australia, and Fig. 521. — Mealy plum aphides clustered on leaf. (After Lowe.) New Zealand, and seems to be widely distributed over the United States. It occurs here on plum and prune and in Europe is said to infest grape, peach, apricot, and nectarine, according to Lowe. The Hop Plant-louse * This species is best known as a pest of hops during the summer and rarely does very serious damage to the plum, though often quite abundant on it. The wingless aphids are light green or yellowish green without any noticeable markings. The winged forms have the same body color, with the head, thoracic lobes, and a few dashes on the abdomen, black. The species may be readily distinguished by the prominent tubercle which projects from the head on the inside of the base of each antenna, and a less prominent tubercle on the basal segment of each antenna. According to the studies of Dr. C. V. Riley and his assistants, the third generation in the spring migrates from the plum to hops in late spring and in fall winged viviparous females give birth to a few young which develop into egg-laying females which * Phorodon humuli Schrank. Family AphididcE. See C. V. Riley, Report U. S. Dept. Agr., 1888, p. 93; W. T. Clarke, Bulletin 160, Cal. Agr.Exp. Sta. 594 INSECT PESTS OF FARM, GARDEN AND ORCHARD mate with winged males which have developed on hops, the winter eggs being laid on the plum and other species of Prunus. In California, Clarke has been miable to find any evidence of the species on plum or other vegetation outside of the hop yards, where he finds the true sexes occuring in the fall, but no evidence of eggs. Hops are often seriously damaged by being reduced in size and weight and from the loss in aroma due to the presence of the aphids in them. The species is of European origin, where it is a well-known enemy of hops, and has become widely dis- tributed in the United States and Canada. Control. — Where it oviposits on plum it may be best con- trolled by spraying as for the other plum aphids in the spring. After it becomes established on hops it may be controlled by spraying with "Black-leaf 40." The Rusty-brown Plum-louse * This species is readily distinguished from others common on plum and prune by the dark rusty-brown color, with the base of the antennae, tibise, and tail a contrasting white. This species has become a very serious pest to plum foliage in the South and Southwest, and we have observed serious injury in New Hamp- shire, so that it is evidently widely distributed. The aphids collect on the tender young twigs, which they stunt or kill, assemble on the under sides of the leaves, which become corrugated and curled from their attack, and when abundant they attack the blossoms and their stems and thus prevent the setting of fruit. In early summer the winged females migrate to various common grasses, such as fox-tail, red top, barnyard grass, crab grass, and others, upon which they breed during the summer, and from which the winged forms return to plum in the fall. They become darker in color late in the season and the wingless, egg-laying female is ahnost black, as is also the small winged male. Control. — The treatment advised for the apple-aphis (p. 537) will be effective for the three species above, while on the plum, and the spraying should be done early in the season before the aphids have become numerous and curled the foliage. * Aphis setarioe Thos. Family Aphididoe. See Gillette and Taylor, Bulletin 133, Colo. Agr. Exp. Sta., p. 41; C. E. Sanborn, Bulletin 88, Okla- homa Agr. Exp. Sta. INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 595 The Black Cherry-louse * This species has long been known as a cherry pest in Europe and during the last fifty years has become generally distributed over the eastern United States, and occurs in Colorado. So far as known the cherry is the only food-plant. Dr. Weed was of the opinion that the aphids left the cherry during late July and migrated to some summer food-plant which he was unable to find, but observations by Gillette and Taylor in Colorado would indicate that they may remain on the cherry, but become so reduced in numbers by their natural enemies that only a few survive during midsummer, and these give rise to larger colonies in late summer and early fall. Both the winged and wmgless forms are deep shining black, the body is rather broad and flat, A2y J Fig. 522. — ^The black cherry-aphis (Myzus cerasi Fab ): 1, apterous vivip- arous female; 2, winged viviparous female — enlarged. (After Gillette and Taylor.) and the honey-tubes are unusually long and are cylindrical. Small winged males and wingless females occur on the foliage in the fall and the latter lay their eggs on the twigs about the buds. Like the black peach-aphis, this species has the habit of accumula- ting in large numbers on the smaller sprouts or limbs near the ground before spreading to the rest of the tree or other trees, so that prompt treatment when first observed will prevent general infestation. Control. — Spraying as for the apple-aphis (p. 537), will control the pest. * Myzus cerasi Fab. Family Aphididce. See C. M. Weed, Bulletin Ohio Agr. Exp. Sta., Tech. Ser., Vol. I, No. 2, p. Ill; C. P. Gillette, Journal of Economic Entomology, Vol. I, p. 362. 596 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Cherry Fruit-fly f The cherry fruit-fly is a native insect whose maggot Hves in the flesh of the cherries, causing them to rot. It is very nearly related to the apple maggot (p. 559) which it very closely resembles in both appearance and Ufe history. Injury by it has been recorded in Massachusetts, New York, Ontario, Pennsylvania, District of Columbia, Michigan and Iowa, so that it is probably generally distributed over the northeastern States. Although its native food-plant is unknown it is probable that it lives on some wild sour cherry. As cherries are always more or less injured Fig. 523. — The cherry fruit-fly {Rhagoletis cingulata Loew.): a, fly; 6, maggot; c, anterior spiracles of same; d, puparium; e, posterior spiracular plates of pupa — all enlarged. (After Chittenden, U. S. Dept. Agr.) by the plum curculio, it is quite probable that injury by this maggot may have been attributed to the curculio and its identity passed unnoticed. Sour and subacid varieties, such as the Morello and Montmorency, are worst injured, but black cherries and indeed all varieties are more or less damaged. The fly is slightly smaller than that of the apple-maggot, being about one-sixth inch long with a wing expanse of three-eighths inch. The body is blackish, the head and legs are pale yellowish- brown, the sides of the thorax are marked with a longitudinal t Rhagoletis cingulata Loew. Family Trypetidce. See M. V. Slingerland, Bulletin 172, Cornell Univ. Agr. Exp. Sta.; F. H. Chittenden, Bulletin 44, Bureau of Entomology, U. S. Dept. Agr., p. 70, and J. F. Illingworth, Bulletin 325, Cornell Agr. Expt. Station. INSECTS INJURIOUS TO PEACH, PLUM AND CHERRY 597 yellow band, the abdominal segments are marked with whitish or pale brownish transverse bands, and the wings are crossed by four blackish bands. The maggot is about one-quarter inch long and is indistinguishable from the apple-maggot. Life History.— The eggs are deposited just under the skin of the cherry from June until August, or probably during the whole season of the fruit. The eggs hatch in a few days and the little maggots penetrate to the pits, feeding on the flesh and forming a rotting cavity very similar to that made by the grub of the curculio. But few of the affected cherries fall from the trees, and as they frequently show but little effect of the damage, the infested fruit may be marketed and the pest thus, spread. When full grown the maggots leave the cherries and form puparia just beneath the surface of the ground, or in the bottoms of baskets or in rubbish, wherever the affected fruit may be. Fig. 524. — Section of a cherry, enlarged to The flies commence to shmv the maggot of the cherry fruit-fly and nature oi its work. Ihe small ngures emerge from these puparia above show the maggot and parent fly nat- by the middle of June in "i"^l ^i^^- (^^^er Slingerland.) New York and are found during the summer months. Control. — There is but little evidence as to practical means of control. Deep plowing in spring should result in burying the puparia so deeply as to prevent the emergence of the flies. Culti- vation is evidently of Uttle value, as the pest occurs in well- cultivated orchards, so that shallow cultivation does not seem to affect the puparia. Chickens have been observed to destroy the puparia, and will doubtless prove as effective as against the apple-maggot where they can be confined beneath affected trees on cultivated soil. The destruction of all fruit, whether windfall 598 INSECT PESTS OF FARM, GARDEN AND ORCHARD or remaining on the tree will, of course, aid in control. Recently a nearly related fruit-fly has been successfully controlled in South Africa by spraying the foliage with arsenate of lead sweetened with treacle or brown sugar, thus attracting the flies which are poisoned by the arsenate, and this method is worthy of trial both for the cherry L uit-fly and apple-maggot. CHAPTER XXVII. SOME INSECTS INJURIOUS TO CITRUS FRUITS* Scale Insects f There are many scale insects injurious to citrus fruit. Possibly taken collectively they are the most important pests of this class of fruit. Their importance is due in part to difficulties encountered in control which do not operate in the control of scale insects on deciduous trees. Dormant sprays, the main dependence for scale control on the latter group of plants, are not available for use against citrus scales. It will not be feasible to discuss all the im- portant scales in detail here but the two natural groups, the armored scales and the unarmored scales, will be discussed separately. Armored Scales f There are several armored scales which are important pests of citrus trees. Of these the most destructive is probably the Purple Scale § present in Florida and the other Gulf States and in Cahfor- nia. This scale resembles the common oyster-shell scale of the Southern States. It is found for the most part on citrus fruits and is of world-wide distribution. It attacks leaves, twigs and fruit and is often seen on fruit in northern markets. The Cahfornia Red Scale or Orange Scaled is more important in *See H. J. Quayle, Bulletin 214, California Exp. Sta.; J. R. Watson, Bulletin 148, Florida Exp. Sta.; W. W. Yothers, Farmers' Bulletin 933, U. S. Dept. Agr.; C. E. Wilson, Quarterly Bulletin, State Plant Board of Florida, Vol. II, No. 1, and various bulletins from the Florida Agr. Exp. Sta., The State Plant Board of Florida, The California Agr. Exp. Sta., The California State Commission of Horticulture and the U. S. Dept. of Agr. t Family Coccidcr. See list of publications given above and special bul- letins mentioned in connection with the different scales. X See previous reference. § Lepidosaphes beckii Newman, See H. J. Quayle, Bulletin 226 California Agr. Exp. Sta. If Chrysomphalus aurantii Mask. See H. J. Quayle, Bulletin 222, California Agr. Exp. Sta. 599 600 INSECT PESTS OF FARM, GARDEN AND ORCHARD California than in Florida, but is present in Florida. It is said to be second only to the black-scale as a pest in California. Adults of this scale are circular, of reddish color and about the size of an ordinary pin-head. There are several generations in the course of the year but these overlap so that young may be found through all the season. The young, like those of the San Jose scale are pro- FiG. 525. — Purple Scale on lemon. duced alive and not hatched from eggs as is usually the case with scales. This scale attacks trunk, branches, foliage and fruit and in- jures the tree by sucking the juices from it. It also injures the appearance of the fruit upon which it may sometimes be seen in the market. The Yellow Scale * is a variety of the California Red Scale and differs from it in its lighter color and slightly different distribution. * C. aurantii var. citrinus Coq. INSECTS INJURIOTJS TO CITRUS FRUITS 601 The Long Scale * is one of some importance in Florida, but is not reported from California as a pest. It is similar in habits and distribution on the plant to the Purple Scale, being often found on the fruit with that scale, but it may be distinguished by its narrower Fig- 526.— The Chaff Scale on lemon. shape. Being about the same length as the purple scale it is mach narrower. They are not always distinguished by the growers. A scale often associated with the red and yellow scales and similar to them except in color, which is more of a Ught gray, is the Greedy Scale f. Its main injury is in disfiguring the fruit for market as it rarely interferes seriously with the growth of the tree * Lepidosaphes gloverii Pack. See Watson, l.c t Aspidiotus camelliae Sign (or rapax Comstock) . 602 INSECT PESTS OF FARM, GARDEN AND ORCHARD Similar to it is the Oleander Scale * which, on account of its fre- quent occurrence on lemons is sometimes called the lemon-peel scale. The two latter forms are common in Cahfornia, but not known to infest citrus in Florida. The San Jose scale (see page 470) is a pest in both localities, but does not do as much damage to the citrus fruits as it does to the deciduous kinds, being largely over-shaflowed by the other scales mentioned. In Florida the most destructive scale is the Florida Red Scale or Round Scale f. It lacks importance from the fact that it is not so widely distributed as some of the others and does not seem to spread so rapidly or to be as generally present in an infested plant- ing. This scale is reddish brown in color with a lighter brown center and is nearly circular. It infests the leaves and fruit and will easily defoliate a tree when it is abundant. The Chaff Scale J, a thin gray form, sometimes completely covers the bark of trees in Florida, especially the bark of the smaller branches. The Snow Scale, § so called on account of the white color of the males, is closely related to the scurfy scale of the apple. Neither the Chaff Scale nor the Snow Scale is seriously injurious. The Unarmored Scales Members of this group lack the separable scale found in the previous group of scales, the protection to the body being provided by a thickened and sometimes hardened body-wall rather than by a secretion from the body wall. They are generally larger than the armored scales and are much thicker bodied, their shape suggesting that of the common terrapin, on which account several species receive local names of terrapin-scale or tortoise-scale. The Black Scale If is the most important of the scale insects in California, being, according to Quayle, the most destructive of the insects attacking citrus fruits in that state. It occurs in Florida but rarely attacks citrus plants there, being more common on oleander and other trees. Its injury is due not so much to its feed- ing habits as to the secretion by the scales of a substance resembhng * A. hederae Comstock. t Chrysomphalus aonidum L. X Parlatoria pergandii Comstock. ^Chionaspis citri Comstock. ^ ,., . « *\Saissetia olece Bern. See H. J. Quayle, Bulletin 223 California Agr. Exp. Sta. INSECTS INJURIOUS TO CITRUS FRUITS 603 the honey-dew of plant Hce which promotes the growth of a black fungus, known as the sooty-mold fungus, on the leaves and fruit, and makes it necessary to wash the fruit. Washing the fruit involves great loss due in part to the cost of the washing, but more to the infection of the fruit with molds through abrasions in the skin made in the process. The sooty-mold fungus on the leaves, al- ^^^^^^ though it lives from the honey-dew *S^^^H and not the leaf, interferes with the ^^IHi growth of the leaf by forming a JtojL dense coating over it. This is in- ^^V jurious to the leaf and to the tree. J^m The Black Scale is large, from one- W^^k eight inch to one-fourth inch long, ^^|^ more or less hemispherical in shape, ^^BP ' and somewhat wrinkled or ridged m^t^ on the surface. The hfe cycle re- ^^^^ quires several months but eggs are wBi produced over long periods and in ^^EU^ ^^^ great numbers, as many as 3000 ^^^^ ^^ from one female, so there appears to ^^^^ be one more or less continuous gen- ^^m eration. 1[^H The Soft Brown Scale,* some- ■■ times called the Turtle Back Scale .^Ik is similar to the one just discussed ^^v but smaller, of a brown color and ^^B lacking the darker markings of the ■■ Black Scale. It is occasionally Fig. 527.— Black Scale (-Samefea . locally injurious in the citrus fruit <^^^^ Bern.), region and is present over a large part of the country, attacking a variety of plants. Its injury in citrus groves is due to the honey- dew and consequent growth of sooty-mold fungus. The adult scales are somewhat more than one-eighth inch long and the shape is less nearly hemispherical. The young are produced alive, eggs being hatched within the body of the insect, and the young attack, by preference, the young growth. There are three or four broods. * Coccus hesperidum L. 604 INSECT PESTS OF FARM, GARDEN AND ORCHARD The Hemispherical Scale * is essentially a greenhouse pest, being found on ornamental plants of many sorts in greenhouses. It has some importance as a pest in citrus plantings as it thrives outdoors in climates suitable for orange growth. It is of a rather uniform brown color, fairly large size and is rather smooth and polished on the surface. Other scales of this type are found on orange, lemon and other trees of this type but none of them is as important as the ones mentioned. In Flori- da, the Wax Scale {Ceroplastes floriden- sis Comstock) charac- terized by a thick covering of white wax, and two other species of the same genus, are frequently to be seen but rarely do serious damage. The Cottony Cush- ion Scale or Fluted Scalef is possibly the most famous of the scales attacking the citrus plants. While not so injurious now as formerly, it threat- ened, for some years after its introduction into CaHf ornia in 1868, the very exist- ence of the citrus in- dustry. Other efforts to control it having failed, a search wasmade by agents of the Department of Agriculture at Washington, for its native home, in the hope of finding there some insect which fed habitually upon it and was capable of keep- ing it in check. In this search they were more successful than other * Saissetia hemispherica Targ. 1 1 eery a purchasi Mask. Fig. 528. — Hemispherical scale, Saissetia hemis- phaerica. INSECTS INJURIOUS TO CITRUS FRUITS 605 agents have been in recent years in the search for similar enemies to other introduced insects for they found, in Australia, which appeared to be its original home, a lady-bug beetle which fed on this scale. Some of these beetles * were sent to California where they were reared and distributed to the infested groves and in a few years had reduced the scale to the status of an occasional pest and it is no longer feared, doing less damage normally now than several other species and being always easily reduced in num- bers by the distribution of the lady- bugs. The Cottony Cushion Scale is more nearly related to the mealy bugs than to the soft-scales, with which it is usually classed. It is brown in color and has some resemblance to the soft or unarmored scales. It takes its common name from the appearance of the females at egg-laying time when they produce underneath the posterior portion of the body a mass of cottony wax which is fluted or furrowed on the upper side and forms a dense cushion. In this cushion the eggs are laid. At ! this stage the scale is not unlike the i common cottony-maple scale of the ' east {Pulvinaria innumerahilis) . ^^ Recognition of this species is easy . ^Hki '■ on account of the appearance of the ^^^ females. Adults are found on the Fig. 529.— Cottony Cushion bark, but young are more Ukely to be Scale. on the foliage. There are three or four annual generations. The scale is generally distributed in CaHfornia, and is present in many localities in Florida. While the lady-bugs will control it, it is necessary to keep watch and see that they are present in infested groves. * Novius (Vedalia) cardinalis Muls. 606 INSECT PESTS OF FARM, GARDEN AND ORCHARD In Florida the State Plant Board collects, rears and distributes these lady-bugs, to the growers, a nominal charge being made for the service. The beetle is commonly called the Vedaha or the Austrahan lady-beetle. There is present in California another effective parasite of the Cottony Cushion Scale, a true fly, of the family Agromyzidcs (Gryptochaetum monophlcehi) . This was introduced from Australia the same time as the Vedalia beetle. Control of Scales in Citrus Groves Since the control measures employed for scale insects are essentially the same as those for the whitefly and the mealy-bugs discussion of them will be deferred and will follow the discussion of those insects. Mealy Bugs * Several species of mealy-bugs occur in citrus plantings as well as on truck and other crops in the South and on greenhouse plants -- • 4--fs#^ am M ^^^ KUl i s ^BK^^KW' '' €■: ^) _ .: . ' . .€? # .S^^^^ll ipm m ppp- Fig. 530. — Lemon infested with the common mealy-bug. After Woglum and Neuls. U. S. Dept. of Agr. and some outdoor ornamentals farther north. The most impor- tant of these is the Citrus Mealy-bug f and since they all have much the same habits and appearance they will all be treated * Family Coccidce, Sub-family DactylopiincB. t Pseudococcus citri Risso. INSECTS INJURIOUS TO CITRUS FRUITS 607 under this head. The mealy-bug is common in all citrus growing regions and is at times a serious pest. It attacks many plants, but prefers the citrus fruits. It is found on all the growing parts of the plants, but prefers sheltered situations as between the leaf-stem and the stem. It also gets into crevices in the bark and sometimes clusters on the stem end of the fruits and between fruits which are hanging against each other. Fig. 531. — A group of common mealy-bugs. Enlarged about 9 times. After Woglum and Neuls, U. S. Dept. of Agr. Mealy-bugs secrete a form of honey dew in which grows a black sooty-mold of fungus which disfigures the fruit and renders wash- ing, with its objectionable features, necessary. If not washed off the fruit they will remain on it after picking and continue to breed causing loss in transit or storage. The eggs are laid in a mass of cottony wax secreted by the females and the young are fairly active. The adults are never permanently attached to their food-plant as are the scales. They breed more or less continuously but there are several generations. 608 INSECT PESTS OF FARM, GARDEN AND ORCHARD They are likely to be more abundant in dry weather, spring and fall in Florida. The insect is resistant to sprays, being protected by its waxy covering and the young are also resistant to fumigation so that the insect is hard to control. It will however, yield to persistent treatment under the methods to be described. Mealy-bugs, Kke most of the other important citrus insects, are subject to the attacks of many kinds of parasitic and predaceous enemies which may, under favorable conditions, entirely eliminate the necessity for artificial control measures. It has been observed in California that the work of these enemies is interfered with by the Argentine ant * which drives away the parasites or destroys them in some stages. It is therefore frequently of advantage to protect the infested trees from these ants, either by banding with some substance which will keep them out of the trees, as sticky tree-tanglefoot, or by poisoning the ants. This is done quite successfully by the use of the following poison as recommended by Woglum and Neuls f from whom the following directions are quoted : " To free trees of ants the ideal procedure would be to eradicate these insects from the area affected. The writers have not carried on any such tests, but the published results of work carried on by the Department of Agriculture against the Argentine ant | would indicate the feasibility of freeing orchards of this pest. The procedure followed with noteworthy success in municipal control work was the distribution throughout the affected area of a poisoned sirup in a suitable container. A paraffined paper bag, with perforations for the passing of ants, containing about a gill of sirup, was used as a container for naihng to trees." " The sirup is made as follows: Granulated sugar pounds — 15 Water pints— 7 Tartaric acid (crystalHzed) ounce — 3^ Boil for 30 minutes. Allow to cool. Dissolve sodium arsenite (C. P.) ounce — ^ * Iridomyrmex humilis Mayr. t Woglum and Neuls, Farmers' Bulletin 862, U. S. Dept. of Agr. J Barber, E. R. The Argentine Ant: Distribution and Control in the United States, U. S. Dept. of Agr., Bui. 377, 23 p., 4 fig. 1916. Newell, Wilmon, and Barber, T. C. The Argentine Ant. U. S. Dept. of Agr., Bui. Ent. Bui. 122. INSECTS INJURIOUS TO CITRUS FRUITS 609 In hot water pint — 1 Cool. Add poison solution to sirup and stir well. Add to the poisoned sirup: Honey pounds — 1}4 Mix thoroughly. "A number of experiments with banding in orchards infested with the Argentine ant have proved the practicability of this method of keeping trees free of ants during their active season, and this method of control is recommended as the most effective one tried. Before the band is applied the tree should be pruned so that the lowest branch is fully a foot above the ground, and all rubbish should be removed from beneath the tree and the soil cultivated to destroy all grass and weeds. The only banding material which has given satisfaction is a mixture * made up as follows: Finely powdered flowers of sulphur . . . part by weight — 1 Commercial tree-banding sticky material parts by weight — 6 " The two ingredients are mixed together thoroughly with a wooden paddle until of a uniform color and consistency. That possible injury may be avoided, this is not applied directly to the bark, although direct application of the commercial sticky tree- banding matei'ial alone has never been noted in California to affect citrus trees seriously. First coat the trunk with a thin layer of paraffin and apply the mixture of sulphur and sticky tree-banding material over this. Paraffin that has a high melting point is preferable, and it is applied with a brush while melted. It hardens almost immediately, after which the mixture just referred to can be applied in a band about 5 inches wide and almost one-fourth inch thick. A single application of this material has kept trees free of ants for several months during warm weather. "Ants that are on trees at the time of banding usually drop off within a day or two unless nests are in the trunk or branches. If nests are present, however, they should be destroyed by applying pyrethrum or some other ant powder, or with a fine spray of gasoHne from a plumber's torch, or with cresolated emulsion applied with a *Compounded by Mr. J. R. Horton of the Bureau of Entomology, U. S. Department of Agriculture. (See Horton, J. R. Some weatherproof bands for use against ants. In Mo. Bui. Cal. State Com. Hort., v. 5, no. 11, p. 419-421. 1916.) 610 INSECT PESTS OF FARM, GARDEN AND ORCHARD 3-gallon compressed-air sprayer. This should be done early in the morning, while the ants are least active. " Inspection should be made weekly for the discovery of rein- f ested trees, the bands being renewed where necessary and the branches of the trees kept from coming in contact with weeds or the ground." Whiteflies* The whiteflies are the most important of the insects attack- ing citrus fruits under the conditions exist- ing in Florida but are not so serious in Cal- ifornia, as they are, as yet, present in that state in only one or two restricted locali- ties. Indications are that, once they are established, they will be as important there as in Florida. According to Watson (1. c.) there are eight species of Fig. 532 — Adults of the common white fly crowd- -whiteflies attacking ing the under surface of new orange leaves. . t ■ • Adults appear shghtly less than normal size. Citrus fruit S in (Morrill and Back.) U. S. Dept. of Agr. Florida. Two of these, the Common Whitefly f and the Cloudy- Winged Whiteflyl are pests of the first importance while a third is occasionally * Family A leurodidae. t Dialeurodes citri R. & H. i D. citrifolii, Morgan. INSECTS INJURIOUS TO CITRUS FRUITS 611 important (the Woolly Whitefly *) . The last named species is al- most perfectly controlled by a Hymenopterus parasite, The Kfe history of all these is essentially the same, as are their habits, and one discussion will fit all reasonably well. The eggs are minute objects laid on the under side of the leaves. The young crawl about and begin to suck sap, staying away from the light as much as possible. They soon become stationary, like scales, and remain so until the growth is completed, when they transform to adults which are minute fly-like insects about one- sixteenth inch long. The wings are white and covered with a fine waxy powder. Injury from whiteflies is the result of their feeding habits which drain the tree of its sap and also of the production by them of quantities of honey-dew, the effect of which is exactly the same in this case as in the case of the scale insects having the same habit, that is, the growth of sooty-mold on all parts covered with the honey-dew and the consequent interference with the function of the leaf and the necessity which arises for washing affected fruits with the attendant loss from the process. Blackening of the trees from the sooty-mold is the most prominent sign of the presence of the whiteflies in number. Control of Whiteflies f Whiteflies maybe controlled by spraying and by fumigation. The practice of these control methods as applied to whiteflies does not differ materially from the same methods as used for scales and mealy-bugs. They are therefore all discussed under the general head dealing with control measures for these insects. Another means of controlling the whitefly, and applicable only to it, is the control by the use of parasites or fungus diseases which attack these insects. There are four of these diseases which are most important in the control of whiteflies, with but one exception they infect the young insects only. Of these the most important is the Brown Fungus {Mgerita wehberi), which appears as brown spots on the under side of the leaves. A young whitefly attacked by one of these spores produces a growth of the fungus from which minute * Aleurothrixus howardii, Quaintance. tSee P. H. Rolfe and H. S. Fawcett, Bulletin 119, Florida Exp. Sta. 612 INSECT PESTS OF FARM, GARDEN AND ORCHARD threads or hyphae extend out in every direction and carry the disease to other young on the same leaf without the production of more spores. The hyph(^ grow around the edge of the leaf to the upper surface and there produce the spores. When the spores are pro- duced they are carried by the wind and other natural agencies and are quite likely to infect all the flies on a tree or even in a grove. This fungus appears mainly in the late summer and in the autumn and grows best in wet weather. It attacks both the Common Whitefly and the Cloudy-Winged Whitefly. The Red Fungus or Red Aschersonia (Aschersonia aleyrodis), is next in importance. It develops in and oh the young fly and does not send out the hyphae as does the brown fungus. It can therefore be carried only in the spore form. The spores are formed in small pits on the fungus growth, such growths being called fungus pustules. This species thrives earher in the season than does the brown fungus and it also is effective against both the common species. The Yellow Fungus, or Yellow Aschersonia (^sc^ersoma ^awo- citrina) is interesting as well as important. In appearance and growth it is almost exactly like the red fungus, but bright lemon yellow. It affects only the Cloudy-winged Whitefly, of which it is an important parasite. The fourth species of importance is called Microcera (Fusarium) and is particularity destructive to the Cloudy-winged Whitefly. It attacks several of the scale insects as well as the whitefly and is of importance in their control. It grows more quickly than the other fungi, requiring less than a week for the formation of spores where the other species require nearly a month. It infests young larvae to the greatest extent, but attacks both eggs and adults as well. It thrives better during cooler weather than do the others, but it needs plenty of moisture. All fungi do best under rainy weather conditions, and it is said that if the rainy season persisted throughout the year there would be no need for artificial measures of control for the whitefly and possibly also for some of the scales. Preservation and distribution of fungi. — These fungi may be preserved until needed by placing leaves with the fungus and spores present on them in cold storage or by drying the leaves and storing them. From such material, cultures may be introduced INSECTS INJURIOUS TO CITRUS FRUITS 613 early in the season before fresh fungus is available. Special di- rections for this should be obtained from the State Plant Board or the State Experiment Station,* (of Florida). The fungus is introduced into groves or trees infested with whitefly but free from fungus, either by placing infected leaves in and about the trees or by making a Virater infusion from the leaves, thus forming an infusion of the si)ores and spraying or sprinkling this on the under side of the leaves. When material is scarce the infusion may be placed in a large pan or bucket and the ends of a few branches of each tree dipped into this, dependence for further spread being placed on the natural methods of dissemination. The recommendation for the use of fungi states that they may not always be depended upon for complete control, but that, in the best practice, use should be made of them in connection with the use of the contact insecticides described. Pure Cultures of Fungi. — Of the several fungus parasites of whiteflies known in Florida, two, namely, the Red Aschersonia and the Yellow Aschersonia, can be readily grown in the laboratory in pure cultures on sterihzed sweet potato. The brown fungus has also been tried, but while a vegetative growth can readily be obtained it has so far refused to produce spores. The methods for growing these fungi in pure cultures were perfected some years ago by the Florida Experiment Station.f When in 1915 the State Plant Board of Florida was organized, the growing of pure cultures of the Red and Yellow Aschersonias became one of the projects of the Entomological Department. Since that time a few hundred to as many as several thousand cultures have been annually produced. A culture consists of the amount of fungus and fungus spores that can be grown in a pint widemouth bottle and is sufficient for starting fungus in an acre grove. More or less may be used but the amount indicated has been found to be quite sufficient. Sterilized plugs of sweet potato were originally the medium upon which these fungi were grown, but it was soon discovered that the addition of a small * See E. W. Berger, Bulletins 97 and 103, and J. R.Watson, Bulletin 123, and Annual Reports for 1907 of the Entomologist and Pathologist, Fla. Agr. Exp. Sta. t See H. S. Fawcett, "Fungi Parasitic upori Aleyrodes citri,'' Special studies No. 1, Univ. of the State of Fla., June 1908. See also, E. W. Berger, p. 12, Bulletin 103, Florida Exp. Sta., 1910. 614 INSECT PESTS OF FARM, GARDEN AND ORCHARD amount of agar improved the consistency of the cultures so that they can be shipped without contents of the bottle becoming mixed up, or disarranged. The presence of the agar, furthermore, permitted allowing the contents of the bottles to cool and harden in a sloping position, resulting in what has been called a "Sweet potato-agar-slant" which has certain advantages for manipulation in the laboratory Control of Scale Insects, Mealy-bugs and Whitefly. Three general methods for the control of the above insects are used. They are, spraying, practiced in California and in Florida with equal success; fumigating, practiced in California, but not so successful under Florida conditions on account of the large amount of rainfall; and control by the encouragement and dis- tribution of fungi parasitic on the insects, this method being adapted to Florida conditions rather than to those which obtain in California, since these fungi usually are favored by excessive amounts of moisture. Spraying. — Spraying for the insects in question is rather increasing in favor as new methods and materials are being per- fected. Formerly it was considered impossible to do successful spraying for these insects because of the close heads and dense foliage of the citrus trees and their lack of a dormant period which would permit the use of insecticides stronger than the foliage could stand and would also permit more thorough treatment of the trunk and branches than is possible where the tree retains its foliage for the entire year. However, sprays have been developed which will kill the insects without injury to the foliage and there are spraying machines with which these sprays can be applied thoroughly with careful labor. Lack of success is likely to be due to faults in the application of the sprays rather than to the inefficiency of the method. In spraying for all the insects in this list several things must be considered. First is the fact that these are all sucking insects which must be hit by the spray to be killed; second is the fact that there are several stages, some of which are more easily killed by spray materials than are others so it is necessary to have a reasonable knowledge of these stages in order to apply the sprays when they will do the most good ; and third, the fact that they INSECTS INJURIOUS TO CITRUS FRUITS 615 breed and increase with great rapidity so that a few individuals escaping the first treatment may in a few weeks make additional treatments necessary, even with the most efficient spraying. Spray materials most widely used are the oil emulsions and miscible oils. In Florida there are two kinds of emulsions used, called the boiled emulsion and the cold-stirred emulsion. Direc- tions for making these are given by Mr. W. W. Yothers in Farmers' Bulletin 933, U. S. Department of Agriculture, and are quoted here as the best available: ''Experiments covering a 10-year period have shown that the best insecticides for controlling white flies and scale insects are those having a base of cheap lubricating oil or what may be called 'paraffin oil.' These oils are made into emulsions according to the formulas following. ''Fish-oil soap at the rate of from 5 to 8 pounds to 50 gallons of water in May, or from 12 to 16 pounds to 50 gallons of water during the winter season, is an effective spray that has been used for many years without injury to the foliage or fruit. ''While both the fish-oil soap and the oil emulsions are effective in killing the whiteflies and scale insects, experience indicates that the latter are far superior to the former under Florida con- ditions. This superiority is due to the physical properties of the oils. The high boiling point and great viscosity possessed by these oils make them operative over a longer period of time after application, and, too, they are only slowly affected by average temperatures and showers. Foliage sprayed with miscible oils remains slightly oily in appearance and to the touch for several weeks after apraying. Fish-oil soap leaves no such evidence that the trees have been sprayed. The oil spray is much less affected by showers than is the fish-oil-soap spray. Summer showers falling after the oil spray has once had an opportunity to dry on the foliage have little effect in lessening the efficiency of the spray. Such showers, however, have a very evident effect upon the number of insects killed by the soap spray. The effective- ness of the weaker strengths of fish-oil soap is much more reduced by showers than is the effectiveness of the weaker strengths of oil sprays. ''In experimental work on a large scale for the control of the citrus white fly the miscible-oil sprays have given better results 616 INSECT PESTS OF FARM, GARDEN AND ORCHARD than have the soap sprays. This greater efficiency seems to be due, not to a higher percentages of larvae and pupae killed when the spray is applied, but to the effect that oil sprays exert upon unhatched eggs or upon the young larvae hatching from them within 10 to 14 days after spraying. The oil forms a film over the eggs which prevents a large percentage from hatching, and the young larvae from those which do hatch are killed either in the act of emerging from the shell or in crawling over the oil-coated leaf. Those who are in touch with the white-fly problem appreciate the fact that no matter how efficacious an insecticide may be in killing larvae and pupae on the leaves at the time the spray is applied, if it does not either kill these unhatched eggs or remain operative long enough to kill the larvae that sub- sequently hatch, much of the benefit of spraying is counter- balanced by reinfestation. ''There are two ways of making miscible-oil emulsions: (1) Without heat; (2) with heat. The first is called the 'cold- stirred emulsion' the second, the 'boiled' emulsion. Both kinds of emulsion are efficient, reliable, and easily made. Cold-Stirred Emulsion. „. , ., Formula. Fish-oil soap: By weight 8 pounds By measure 1 gallon Paraffin oil, 24 or 28 Baume 2 gallons Water 1 gallon '^Directions for 'preparation. — In preparing the stock mixture," the soap should be put into a receptacle of about five gallons capacity and the oil added while the mixture is being vigorously stirred. It is important that the oil be added in small quantities at first, and that the stirring be sufficient to keep the oil and soap in the form of an emulsion after each addition of oil. Thus, at first about a pint of oil should be added to the soap and the mixture stirred until no free oil appears. As the amount of oil is increased it should always be stirred or mixed thoroughly before the next addition is made. After the required amount of oil INSECTS INJURIOUS TO CITRUS FRUITS 617 has been added and after free oil has ceased to appear on top of the soap, the water is slowly poured in, about 1 quart at a time As previously stated, the only apparatus required to make this formula in a small way is an ordinary galvanized iron pail and a paddle. "The foregoing formula may be modified under certain con- ditions, as the quantity of soap will depend largely upon the time consumed in adding the oil and the amount of stirring; the amount of soap being lessened if the stirring be uniform and ample time be taken in the careful preparation. If it be desired to make this formula on a large scale, a 300- gallon cylindrical tank may be fitted with paddles, which are attached to a shaft in a vertical position, occupying the center of the tank. The shaft is fitted with a beveled gear on the upper end. A horizontal shaft is then connected with the vertical shaft by means of another beveled gear, while the other end has a pulley to connect with the engine. A series -of brakes should be fitted to the sides of the tank to prevent the entire mass from turning around with the paddles. An entire barrel of fish-oil soap may be placed in this tank and the stirring begun at once. Two barrels of oil may then be run into the soap through an inch or l|-inch hole in the end of the barrel, or the oil may be run out of the bung-hole. After the oil has been added, either one-half or two-thirds of one barrel of water can be added to complete the preparation of the stock solution. In the final spray this should be so diluted as to contain about 1 per cent of oil by adding 1 gallon of the stock solution to 50 gallons of water. "It is also highly practicable to fit up a 50-gallon barrel in the same way as described above for the 300-gallon tank. By attaching a crank to the horizontal shaft the mixer can be run by hand instead of by an engine. Such a mixer, designed and used by Mr. J. A. Stevens, De Land, Fla., has been found practicable. The writer has used an ice-cream freezer for making an emulsion, by removing the can and adding a false bottom of 1-inch board to hold up the stirring gears. In fact, many different types of mixers can be constructed, depending on the material available and the scope of the work involved. 618 INSECT PESTS OF FARM, GARDEN AND ORCHARD Boiled Emulsion. Formula. Parafl&n oil 2 gallons Water 1 gallon Fish-oil soap 2 pounds or Hard soap 2 pounds "Directions. — Put oil, water, and soap into a kettle or other vessel that will stand fire, and heat to the boiling point. While still very hot, pump the material into another vessel and then back again. Emulsion can not be made by this formula without a pump; stirring is not sufficient. "Dilute to make 200 gallons of spray material. " For making the above formula the writer has used 9 and 15- gallon kettles, wash boilers, and 100-gallon oil tanks with uniform success. " If it is desirable to make this formula on a somewhat larger scale, the materials can be heated in a large kettle or other vessel and then dipped into a barrel pump outfit and the mixture emulsi- fied by pumping it back upon itself. For safety it is best to have all the material pass through the pump twice, but it must not be pumped after it has become cool. Excessive pumping will break up a good emulsion. It can also be heated in a large galvanized oil tank having a capacity of 4 barrels and emulsified by means of the spraying machine. In this case the suction hose should be put into the tank of hot material and the discharge hose into the spray tank. For the second pumping, put the suction hose into the spray tank and the discharge hose into the storage barrels. When the spraying machine is used for this purpose, an old suction hose should be used, as well as a discarded piece of hose for the discharge end. This should be not more than 10 feet in length. The material should be run through an ordinary nozzle with the disk left off. The overflow will not emulsify this material. " Owing to the high temperature of the mixture, pumps used for emulsifying should have metal valves. If made of other material their period of usefulness is very short. It should always be remembered that a pressure pump must be used for emulsifying. The writer has never succeeded in making an emulsion with a rotary pump. INSECTS INJURIOUS TO CITRUS FRUITS 619 "Difficulties that may arise in making the boiled formula are: (1) A lack of sufficient heat; (2) improper pumping; (3) an improper emulsifier. In many tests the water and soap only were heated, and failure to produce a perfect emulsion resulted in every instance. On thB other hand, when all the materials were heated together a perfect emulsion was secured. The materials should be heated until a slight foam or a few bubbles appear, but it is not necessary to boil for any length of time. "Some growers have failed because they attempted to stir the materials together with a stick, and others because they used a rotary pump. Neither of these is satisfactory. "The emulsifying agent is very important. There is no doubt that potash fish-oil soap is the most satisfactory of all soaps for the making of any of these emulsions. When this material is used the oil very seldom separates and the resulting emulsions never become too thick to be poured or handled conveniently. On the other hand, when hard soaps are used which are made from caustic soda and fats containing large proportions of stearin and small quantities of resin, the emulsions separate on cooling, and will cause much trouble in mixing on the day after they are made. If the emulsion made from any hard soap found on the market is used on the same day that it is made no trouble will be experienced. The 'cold-stirred' formula is difficult to make with hard soaps. The writer has found it impossible to make emulsions by using any of the soap powders, even if flour is used as a stabilizer. "Before any spray material is applied to a tree it should be tested to determine if it is a perfect emulsion. To do this, add a small amount to some soft water; if no oil floats or no thick, greasy scum forms, it is satisfactory. If fi*ee oil appears the emulsion is imperfect and should not be used. Great care should be used to stir the contents of the barrel thoroughly before any test is made. "Just at present the boiled-emulsion formula is the one which will appeal to the average citrus grower in Florida. It is, beyond all question, the cheapest effective insecticide for white flies and scale insects. "The oils used in the making of these formulas usually test from 24° to 32° Baume and have a viscosity not less than 200. 620 INSECT PESTS OF FARM, GARDEN AND ORCHARD The best oils for spraying purposes have a viscosity of about 300 to 400 and they may be purchased from any of the oil companies operating in the citrus-growing belt. Petroleum fuel oil and distillate or gas oil may also be used and when applied should be used at twice the strength indicated for the lubricating oils. The soaps may be purchased from any grocery or fertilizer company. Proprietary Miscible Oils. "There are several proprietary miscible oils on the market which the writer has found to give highly satisfactory results. These should be diluted so that the spray material will contain somewhere between ^ per cent and 1 per cent of oil. The writer would advise the use of oil emulsions when diluted to about 1 per cent. Experience indicates that such substances as rosin oil and sulphuric acid should not be used in proprietary insecticides." Use of Fungus Diseases. — A method for the control of some citrus insects, particularly the whiteflies, in Florida, is the artificial dissemination of fungus spores causing certain fungus diseases to which these insects are susceptible. The discussion of the fungi and methods used is included with the discussion of the whiteflies as this method is not so extensively used for other insects. There are, however, four * principal fungus parasites or dis- eases, of scales that are at times very effective in the natural control of citrus scales in Florida and the Gulf Coast. These are the Red-headed Scale-fungus (Sphaerostible coccophila Tul) the White-headed Scale fungus {Ophionectra coccicola E. & E.), the Black Scale fungus {Myriangium duriaei Mont), and the Pink Scale fungus {Microcera fujikuroi Miyabe & Sawada). The first of these infects and kills the purple scale, long scale and chaff scale and several scales infesting deciduous trees, including the San Jose; the second infects the purple scale and long scale; the third the purple scale, chaff scale, long scale and San Jose Scale; the fourth the Florida red scale and purple scale. * See P. H. Rolfs and H. S. Fawcett, Bulletin 119 (Revision of 94). Fla. Exp. Sta. for the first three fungi named herewith. See J. R. Watson, Report of Entomologist, Annual Report 194, Fla. Exp. Sta. for the 4th or pink scale fungus. INSECTS INJURIOUS TO CITRUS FRUITS 621 These fungi are generally introduced or distributed in scale- infested trees by tying small pieces of fungus material (2 or 3 inches long) to twigs or branches having the most scale. The fungus material may also be rubbed up in water and the resulting infusion of spores and water sprayed into the trees or mixed with the infusion of spores used for distributing the whitefly-fungi Fumigation.* By all means the most popular and efficient means of control for citrus fruit insects in California is fumigation with hydrocyanic acid gas. General discussion of the nature of this gas and its Fig. 533. — Fumigation of citrus trees. Some steps in preparation. After Woglum, U. S. Dept. of Agr. preparation will be found in the chapter on insecticides in this volume. The application of the process to outdoor conditions for use to kill insects on trees is, in itself, a matter of special study. The work in California is usually done by contract by concerns which make that work their business, but the grower should have an idea of the nature of the process in order to be able to tell whether the work is being done properly. The fumigating season extends from August to January and the work should be done when the temperature is not either unusually high or unusually low. It is usually done during the night. *See R. S. Woglum, Farmers' Bulletin 823, U. S. Dept. of Agr. and bulletins of the California Agr. Expt. Station. 622 INSECT PESTS OF FARM, GARDEN AND ORCHARD The method consists, essentially, of the enclosure of the trees to be treated, in individual tents made of material as nearly im- previous to the gas as possible and of generating in the tents gas according to a variable table, based on the cubic content, the amount of leakage, which latter is less in proportion for large trees than for small, and upon other factors. Very accurate dosage tables have been worked out and are available wherever fumigation is a common practice. Time of exposure to the action of the gas is from 45 minutes to one hour, the same as for deciduous trees being fumigated in houses for San Jose Scale. Special machinery for the generation of the gas is used by the large fumigating concerns. With these the gas is generated out- side the tents and piped into them and the necessity for separate generating outfits for each tent is done away with. Fumigation has been tried rather extensively in Florida, but not so well adapted for Florida conditions as for those in California and so is not recommended for use in Florida. As mentioned before in connection with fumigation, it should not be undertaken except under the direction and advice of experts as otherwise there is danger to the trees and to the operator. The Citrus Thrips.* The Citrus Thrips is one of the smallest members of a group in which the largest species are considered as minute insects. It has been known to be injurious to citrus fruits for a quarter of a century but the injury was not generally recognized until about ten years ago, on account of the small size of the insect. So far as is now known it is confined almost entirely to California and is not found in the gulf states. In Florida a different species, the Florida Flower Thrips f is similarly injurious. The thrips sucks the juices from foliage and fruit and kills the cells surrounding its puncture. These dry up and form character- istic scabs and much of the injury is due to their thus scabbing the fruit, especially around the stem end where they cause a condition described as "stem-end ring." They also cause curling of the leaves and a grayish discoloration and interfere in this way with * Scirtothrips citri Moulton. See J. R. Horton, Bulletin 616, U. S. Dept. of Agr. t Frankliniella bispinosus Watson. INSECTS INJURIOUS TO CITRUS FRUITS 623 the growth of the plant. Injury to young fruits often results in a large amount of dropping. Splitting and other deformation of the fruit is another evil effect of thrips in- jury. The California thrips is trans- ported from place to place for the most part on young trees where it is present in the egg stage. Local spread is the result of the flight of the adults. It is not confined to the citrus plants, but feeds on several others such as grape, pomegran- ate and apricot and these may serve as sources of infesta- tion. The life cycle requires about a r month and there Fig. 534.— Citrus Thrips: a, Young nymph; 6, Full grown are from six to eight nymph; c, Adult. After Horton, U. S. Dept. of Agr. generations which overlap so that they are practically indistin- guishable. The winter months are passed in the egg stage. The Florida flower thrips is present everywhere and infests the blossoms of many plants. Control. — Natural enemies are an important factor in thrips control. They include larvae of the lace-wing flies (Chrysopa californica Coq.), lady-bug larvae, some of the assassin-bugs (Reduviidoe) several species of spiders and a fungus disease. In some years these enemies will render artificial control measures unnecessary. Spraying is resorted to for control where any artificial measures 624 INSECT PESTS OF FARM, GARDEN AND ORCHARD are necessary. Horton 1. c, summarizes the spraying recommenda- tions based on spraying tests made in California as follows: "In the tests the following insecticides and combinations gave the best results. Any of these mixtures may be relied upon to give satisfactory control when properly applied. 1. Lime-sulphur solution. — If the hme-sulphur is of a density of 36° Baume, dilute 1 gallon with 56 gallons of water; if of a density of 33° Baume, dilute 1 gallon with 50 gallons of water. 2. Sulphur-soda solution. — Two gallons of the stock solution, prepared as described diluted with 25 gallons of water. * 3. Lime-sulphur and tobacco extract (40 per cent nicotine sulphate). — Dilute 1 part of the Hme-sulphur, if 34 to 36° Baume, Fia. 535. — Graphic illustration of the seasonal activities of the citrus thrips as related to blossoming and later growth periods of the orange and indicating also the spray periods. After Horton, U. S. Dept. of Agr. with 86 parts of water; if 30 to 33° Baume, with 75 parts of water. Then add 1 part of the tobacco extract to 1,000 parts of the lime- sulphur as diluted above. 4. Tobacco extract (40 per cent nicotine sulphate) . — Dilute 1 part with 800 parts of water. Lime-sulphur and soda-sulphur solutions are more effective against the citrus thrips than any other mixture thus far tested, and particularly the lime-sulphur at the strength stated above- * The sulphur-soda solution was prepared as follows: Powdered sulphur 30 pounds Powdered caustic soda (98 per cent) 15 pounds Water to make 30 gallons The sulphur was made into a paste with water and the soda added, while the mixture was constantly stirred, in sufficient quantity to cause boihng, a Httle water being added occasionally to retard the cooking. When all the sulphur was dissolved, enough cold water was added to make a stock solution of 30 gallons. A clear, amber liquid, much resembling good lime- sulphur, was the result. INSECTS INJURIOUS TO CITRUS FRUITS 625 A large percentage of the thrips can be killed by spraying with this solution, and there is a further effectiveness due to its decompo- sition for a long period after deposition on the leaves. In orchards sprayed with good lime-sulphur the sulphurous odor is often strong for two months or more after the appHcations. The decomposition products repel the thrips, which are slower to reinfest orchards so sprayed than those sprayed with solutions that soon evaporate and leave no trace. "Tobacco extracts when used at the proper strengths are also very effective. Both tobacco extract and lime-sulphur, when mixed together, are effective in weaker solutions than when diluted with water alone. Contrary to expectation, the addition of soaps to tobacco extract did not give increased value to the tobacco in these tests. Soap solutions used alone appear to be worthless at the dilutions tested. "Resin wash at any strength practicable for use on the orange trees in this section is worthless. At the greatest strength used in these experiments it failed to reduce thrips injury to an extent worthy of attention. It is, furthermore, very injurious to fruit and foliage. "Plain water spraying was utterly ineffective, demonstrating that merely striking the thrips with a liquid at high pressure to wash them from the trees has no appreciable effect in dimin- ishing their numbers. A few hours after spraying with water there remained on the trees as many hving, active thrips as before spraying." The Florida Flower Thrips * The Florida Thrips is larger than the true citrus thrips, being about one twenty-fifth of an inch long while the other is frequently less than one-half that size. It is of a yellowish or yellowish-red color and may be observed most easily in or about the blossoms of the orange. It injures the fruits and plants in much the same way as does the citrus thrips but is more Ukely to destroy the blossoms or the fruit just as it is setting by making its way down into the flower to the ovary which it attacks. Its injury is more *Frankliniella bispinosus Watson. 626 INSECT PESTS OF FARM, GARDEN AND ORCHARD noticeable where there is a light amount of bloom, where the bloom is heavy the injury serves in a way as a natural thinning and may be beneficial. Dis- figuring of the fruit is a source of some loss from this insect. The life his- tory resembles that of the citrus thrips but there are probably more generations. They may be controlled, where control measures are essential, by the methods outlined for the citrus thrips. Fig. 536. — Florida Flower Thrips. From Watson after Dozier. Enlarged (Florida Agr. Exp. Sta.)- The Rust-mite or Silver-mite * According to Watson, the rust-mite is, in Florida, out-ranked as a pest only by the white fly and the purple scale. In CaH- fornia it is less important being restricted in its distribution, and called the ''Silver-mite" on account of its silvering effect on lemons. It was imported into California from Florida. The rust-mite is just visible to the unaided eye, is rather elongate and broader at the anterior end, tapering to a rather long point toward the posterior end. The eggs are few in number but hatch in a short time and the life cycle may take a period as short as two weeks. In consequence the mul- tiplication, during favorable seasons is very rapid. The broods are inseparable. Mites injure the foliage by sucking oils from the cells and in this way in- jures the trees. Their chief injury is, however, to the fruit which they at- tack in the same way. Here they cause Fig 537. — Orange rust-mite: a, dorsal view; b, lateral view, enlarged, the dot in circle indicating natural size; c, leg; d, egg with embryo just about ready to hatch more enlarged. (After Hub- bard) U. S. Dept. of Agr. * Eriophyes oleivorus Ashmead. See H. Exp. Sta. Class Arachnida, order Acarina, J. Quayle, Bulletin 234, Cal. Family Eriophyidop. INSECTS INJURIOUS TO CITRUS FRUITS 627 arusseting of the fruit which reduces its quality mainly by detracting from its appearance but also by reducing the size. Oranges and grapefruit are the greatest sufferers in Florida. Russeted fruits may frequently, even now, be seen on the market. Control of the Rust Mite. — Weather conditions are a factor in the check of the mites, cold and wet weather being unfavorable to their development. These can not be relied upon to prevent damage and spraying is practiced wherever the mites are abundant. Sulphur is the best insecticide for these pests. It may be apphed in the form of a dust, mixed with hydrated lime which is used as a carrier, at the rate of one part hme to three parts sulphur. The dusting outfits discussed in the chapter devoted to spraying apparatus are suitable for use in applying this material, but care must be used to see that the dust carries through the dense foUage of the trees. Free sulphur mixed with water or with water and soap is a good spray for the mite. Four or five pounds of sulphur, four pounds of soap and fifty gallons water, are about the proper proportions. Commercial lime-sulphur testing 32°, Baume scale, should be diluted with seventy-five parts of water and will make a very good treatment for the mites. Soda-sulphur spray, made as described for the control of the thrips and diluted at the rate of one to forty, is another effective spray. Thoroughness is as important as for the treatment of other citrus pests. Red Spiders * These pests are, Uke the mites, members of the class Arachnida and the order Acarina, being, in fact, true mites themselves. They are larger than the rust mites and one species is quite red in color, being called the Florida red-spider, while the other is * Tetranychus mytilaspidis Riley (or T. citri McGregor. ) and T. sex- maculatus Riley. See H. J. Quayle (1. c). 628 INSECT PESTS OF FARM, GARDEN AND ORCHARD more greyish and has six dark spots which suggest the specific name and the common name of the six-spotted mite. Red-spiders are common in the spring or during dry weather. Fig. 538. — Red-spiders: The Citrus Red-spider, on the left; The Six-spotted mite on the right. After Quayle, California Agr. Expt. Sta. They feed on the juices of leaves and fruits and cause russeting and motthng of the fruit. Often they remain upon lemons in storage and cause injury during the curing process. Fig. 539.^The green lace-wing, Chrysopa californica Coq., an important enemy of red-spiders. After Quayle. Control is the same as for the rust-mite, the compounds of sulphur and sulphur in the free state having been found to be the best treatment for all forms of mites. INSECTS INJURIOUS TO CITRUS FRUITS 629 Diabrotica soror * The most common of the leaf-beetles on citrus fruits on the Pacific coast are the members of this species which is almost identical with the twelve-spotted cucumber beetle or Southern corn-root worm. It attacks the tender foli- age of the orange but rarely damages the lemon. The larva, like that of the cu- cumber beetles, feeds on the roots of plants where it is little noticed. Control. — On small trees the beetles may be jarred off into tar or oil on screens while they are sluggish in the early morn- ing. On larger trees they must be poi- soned. Lead arsenate paste at the rate ^^"- 540.— -Z)i a 6 ro -' 4. V ■f .,> .^ '"' ; '.T * ^ FiG."593.— The cattle tick (U. S. Dept. of Agr.): 3, mature female with eggs; 4, ticks attached, to the hide; 5, blood cells containing Babesia organisms; 10, various stages of ticks. Natural size except 5, which is enlarged 1,000 times. weeds and transfer themselves to cattle at the first opportunity. If they fail to do this they die, but not necessarily for three or four months. On cattle they attach themselves to the tender and protected parts and suck blood, maturing in warm weather in some SIX weeks. If the parent of these ticks was from an infected animal, INSECTS INJURIOUS TO DOMESTIC ANIMALS, Etc. 675 they may infect the new host with the Texas fever at this stage, even though they are so small as to be scarcely visible. Texas fever is caused by a minute protozoan animal of the same general group as the parasite causing malaria (Babesia higemina.) FIELD NO.Z CORN. cohve/is riUD N0.3. COTTON FOLLOWED BV CRIMSON CLOVCR, V£TC». eun C10V£R OR Rye riELD N0.4-. 0/IT6, COU/PEAS, BEtMUO/l, BUR CLOVtn HOVE THE HERD moM 7W/5 FIILD TO FIELD N0.3. FTBR. IS.MOIfEJHCHlFlD TO FIELD NO 4-. becomes the neiv p/isture:. wiiiim HOUSE FIELD NO 1 OCT IS MOVE H£RD TO FIELD NO.Z. PL/INT IN 0/!T.5 fiNO FOLLOW WITH COWPM^. Fig. 594. — Plan for freeing cattle and pastures from ticks by rotation, requir- ing eight months, U. S. Dept. of Agr. It passes from the body of the infected female, no one knows just how, into the eggs so that all her progeny are infective. Appar- ently healthy cattle from permanently infected districts are usually carriers of the disease but have developed immunity to the effects. They are as dangerous as sources of infection for the ticks as are the cattle sick with the disease. It has been definitely shown that the disease can not be trans- mitted in nature in any way except by the bites of the infected ticks. That being the case, the obvious way to eliminate the disease is to destroy the ticks. The U. S. Department of Agri- 676 INSECT PESTS OF FARM, GARDEN AND ORCHARD culture and the authorities in several of the southern states have worked out a plan whereby it is possible to eradicate the tick from the entire Texas fever area. This makes use of the habits of the ticks and the fact that they have no alternate host. The general scheme is a system of rotation of pastures. Cattle are removed from infested pastures, dipped to free them from ticks remaining on them or not, depending upon the number of pastures available. riUD NO. 2. OATS COWPtAS /IND eunciov/ER. FIELD N0.3. CORN. C0IVPU3. FIELD NO.^ COTTON. RYFlUND In/INTCR LCGVMCS. HOVe HffiO TO F/fLO NO J C/ITTLf W/UBf fRff or TICKS BY DZC.20 B£TWE[N THIS DATE AND FEBFI. 15 HOVE THC HCRDTOrieU) NO.*. M/>Fl.iMOVE THE HERD TO FICLD NO. m. mu5i. PlBMflNENT I 1 PASTUFtE OCT/5 MC FltLD NO./ VETHCHCFIC NO. 2. B. TO FIELD ' iJUlYlMOVlH ; iKTfP ALL A 1 ir/ftO UNTIL ] irfiff or r/c FIELD NO in tRDTOPASTUne NO 1 NIMflLS OUT OFTHIS MflFI 1, UIHCN IT WILL B. BE Fig. 595. — Plan for freeing cattle and pastures from ticks by rotation, requiring four months, with new pasture, U. S. Dept. of Agr. The infested pasture is then plowed up or allowed to remain idle for some four months by the end of which time all ticks in it will have died. If there are tick free pastures available, the cattle from the first pasture may be dipped to kill the ticks upon them and then placed in the tick-free pasture, care being taken not to introduce, at any time, tick-carrying cattle into this pasture 678 INSECT PESTS OF FARM, GARDEN AND ORCHARD After four months they may be removed back to the original pasture. If, however, no tick-free pasture is available, a different scheme is used. The cattle are moved after as many of the adult ticks have dropped to the ground as are likely to drop off soon. They are then taken to another pasture, still infested at this time. Here they remain not more than twenty days when they are re- moved to a