SB 945 .S2 R5 Copy 1 State of HI)obc Jslanb Qn^ |Pl•ol1i^cnce ^plantations. THE SAN JOSE SCALE ( Aspidiotus pernieiosus, Comst.) METHODS OF TREATMENT. A. E. STENE . FiQ. 1.— Female San Jose Scale. After Atwood. See page 24. Joint Bulletin of the State Board of Agriculture and Extension Department of the Rhode Island College of Agriculture and Mechanic Arts. 1908. s.%"°i* ERRATA. In the second paragraph on page 13, line five should read as follows : ^^have fallen in the autumn, or just before they come .out in the spring." Note further discussion of this topic on page 64, and re- member that the principal spraying for the San Jos6 Scale is given when the trees are dormant. Summer spraying with ker- osene emulsion is sometimes given, but only to check the scale until eflfective winter treatment can be given. state of HI)obc Islanb anb prouibeiuc plantations. THE SAN JOSE SCALE (Aspidiotus perniciosus, Comst.) AND METHODS OF TREATMENT. A. E. STENE. Fig. 1.— Female San Jose Scale. After Atwood. See page 24. Joint Bulletin of the State Board of Agriculture and Extension Department of the Rhode Island College of Agriculture and Mechanic Arts. 1908. g^f 33 1908 r-3y^^ PREFACE. This bulletin is written in response to a very urgent demand for information on the San Jos4 scale, as evinced by the hundreds of letters which come into the office of the Extension Department of the College every year with questions regarding this insidious fruTf pest and methods of destroying it or preventing its ravages. The bulletin is divided into two parts. The first part, in large type, is in the nature of a summary, and presents briefly the essentials in formulas and directions for treatment of the scale for quick perusal and for those who do not care for a further study of the subject. With each of the statements in the summary, page references are given to the second part of the bulletin. The second part of the bulletin takes up a fuller discussion with an endeavor to present a history and description of the scale and methods of dealing with it in the light of present knowledge and practice such as the up-to-date Twentieth Century farmer is demand- ing. The bulletin contains but little original material, except such general observations as have been made on the behavior of the scale under local conditions and the tabulation of losses as shown by in- formation obtained through the circular sent out the past autumn to the names on the mailing list of the Rhode Island Experiment Station. An endeavor has been made to present the gist of information which seems, in the opinion of the writer, essential to a fairly com- plete knowledge of the scale and methods of treatment, but un- doubtedly much has been left out, and if anyone wishes to pursue the subject further, he can refer to the following books and publica- tions, from which the writer's information i^ largely drawn: 4 THE SAN JOSE SCALE. Economic Entomolog}^, by Dr. John B. Smith, pubhshed by Lip- pincott. Fumigation Methods, by Willis G. Johnson, published by Orange Judd Co. Spraying of Plants, by Lodeman, published by the Macmillan Co. Bulletins of the N. Y. State Museum at Albany, by E. P. Felt. Bulletins by Dr. Howard and Dr. Marlatt and others of the De- partment of Agriculture at Washington. Bulletins of various experiment stations in the United States, but principally those of New York, Delaware, Massachusetts, Con- necticut, California, and Washington; also articles from the Rural New Yorker, Country Gentleman, and the New England Homestead. ACKNOWLEDGMENT. The writer is greatly indebted to the Bureau of Entomology, De- partment of Agriculture, at Washington, for co-operation in securing estimates of damage done by the scale; to the Rhode Island Ex- periment Station for the use of mailing machine in sending out cir- cular letters ; to the Federal Department of Agriculture and various experiment stations, and manufacturers of spray apparatus, for use of cuts, full credit of which is given elsewhere; and to the following persons for submitting estimates of value of fruit trees: L. G. K. Clarner, Arnold's Mills, R. I.; Cyrus Miller, Haydenville, Mass.; Prof. Craig, Cornell University: Prof. U. P. Hedrick, New York Experi- ment Station, Geneva; Prof. William Stuart, Vermont Experiment Station ; and Geo. T. Powell, Ghent, N. Y. CONTEXTS. Preface 3 Contents 5 Summary 9 Introduction 14 Popular Fallacies Regarding Insects and Their Control 16 General History of the San Jose Scale 20 History in Rhode Island 21 Methods of Detecting the Scale 22 Life History 23 Description of the San Jose Scale 25 Host Plants 27 Natural Enemies of the San Jose Scale 32 Means of Distribution of the Scale 34 Losses Due to the Scale in Rhode Island 35 Status of Fruit-growing as Affected by the Scale 38 Future Prospects 40 Chances of Saving Trees Badly Infested 41 Does it Pay to Spray 41 Present Means of Controlling the San Jose Scale 42 General Orchard Treatment 42 Spraying 44 Brief General History of Spraying for the Scale 44 The Lime-Sulfur Wash 46 Formula for Lime-sulfur Wash Generally Recommended at the Present Time 48 Ingredients of the Lime-sulfur Wash 49 Apparatus for Preparing the Lime-sulfur Wash 51 Chemical Composition 52 Other Lime-sulfur Remedies 55 Remedies from Petroleum 56 Kerosene Limoid Mixture 57 Miscible Oils 58 Proprietary Remedies from Petroleum 60 6 THE SAN JOSE SCALE. Comparative Value of the Lime-sulfur and Miscible Oils 60 Miscellaneous Spray Solutions for the San Jose Scale . . 61 Whale Oil Soap 61 Resin Wash 62 A New Wash Proposed by the U. S. Dept. of Agriculture. ... 62 Comparative Cost of Spray Solutions 63- The Time of the Year to Spray 64 Methods of Applying Spray Remedies 64 Spraying Apparatus 65 Fumigation with Hydrocyanic-acid Gas 74 Orchard Fumigation 76 Fumigation of Nursery Stock 77 Apparatus, Chemicals, and Methods of Fumigating Nursery Stock 78 The Fumigation House 80 Fumigation of Peach and Nectarine Houses for the San Jose Scale . 83 Directions for Fumigating Peach and Nectarine Houses . . 84 The Operation 86 Dipping Nursery Stock 87 Additional Notes and Explanations Regarding Illustrations — Acknowledgment for use of Cuts 89 Notes 89 LIST OF CUTS. Page Reference Figures. of Cut. Page. 1. Female San Jose Scale 1 24 2. San Jose Scale on Twig 9 23 3. Male San Jose Scale Insect 20 26 4. Magnifying Glass 22 23 5. Underside of Female showing Sucking Tube 24 26 6. Development of the Scale 25 23 7. Scale of Male San Jose 25 26 8. Cut showing Characteristic form of Annal Plate of Female, as seen under the Microscope 26 9. Microweisia misella Preying on San Jose Scale 32 33 10. Strainer for Straining Spray Solutions into Tank 51 11. Compressed Air Knapsack Sprayer 66 66 12. Large Tank with Agitator, for Large Hand or Gasoline Pump. 67 13. Type of Double Acting Tank Pump 67 67 14. Bamboo Extension Pipe 68 72 15. Short Extension Pipe for Use with Bucket or Knapsack Spray- ers 68 72 16. " Y " for Attaching Two Nozzles to One Lead of Hose 68 73 17. "Mistry"Vermorel Nozzle 68 72 18. "Mistry Junior" Nozzle 68 19. " Demorel" Nozzle 68 73 20. Boiling Lime-sulfur with Steam 69 51 21. Boiling Lime-sulfur with Kettles 70 51 22. Home-made Strainers 71 23. A Recent Form of Vermorel Nozzle 72 73 24. A Type of Vermorel Nozzle without Plunger 72 25. Battery of "Spramotor" Vermorel Nozzles 73 73 26. \ / 85 . . f Cuts Illustrating Method of Ascertaining Contents of \ 27. y \ -"^ 85 . . V Fumigation Houses J 28. / V 86 . . 29. Dipping Nursery Stock, Roots and Body 87 88 30. Dipping Nursery Stock, Body only 87 88 8 THE SAN JOSE SCALE. Reference Plates. Page. I. Frontispiece, Part of Large Orchard Destroyed by Scale. East Providence II. San Jose Scale on Kieffer Pear, etc III. Fig. 1. Picture of Scale on Bark 25 Fig. 2. Fumigation Utensils 78 IV. Good Culture in Apple and Pear Orchards 42-43, 90 V. Mossy Top of Apple Tree; A Capital Place for Scale 91 VI. High and Low Training of Apple Trees 42-43. 91 VII. Tall Pear Tree on Which the Scale must be fought at a Great Disadvantage 42-43, 91 VIII. Thorough Pruning and Spraying for the San Jose Scale 43, 91 IX. A Well-Sprayed Orchard X. Peach Tree badly Infested with the San Jose Scale XI. Small Portable Barrel Pump 67 XII. Fig. 1. Barrel Pump Showing Agitator 67 Fig. 2. Bucket Pump 67 Fig. 3. Gasoline Power Sprayer 68 XIII. Fig. 1. Vice-Admiral 67 Fig. 2. Knapsack Spray Pump 67 Fig. 3. Tower on Tank ; 73 Fig. 4. Tower on Tank; Machinery in Operation 73 XIV. Fig. 1. Invincible Mounted Sprayer 67 Fig. 2, Invincible Mounted Sprayer, Gasolene Power XV. Niagara Gas Sprayer with Tower 73 XVI. Fig. 1. Plant for Preparing Lime-sulfur Wash with Steam 51 Fig. 2. Cooking Lime-sulfur Wash with Steam 51 XVII. Hexagonal Fumigator for Trees 76 XVIII. Box for Fumigating Nursery Stock 81-82 XIX. Fumigation House for Nurseries 80-81 Fig. 2.— San Jose scale on twig, enlarged five times. After Atwood. SUMMARY. Injurious insects take an enormous toll from the pro- ducts of the farm, garden, and forest. It amounts to from six to eight hundred millions of dollars a year. Pages 14 to 16. Erroneous ideas regarding the character of injurious insects and plant diseases lead to a great deal of useless expense and labor in the attempts to control them. Pages 16 to 19. The San Jose scale was introduced from China into the San Jose Valley of California sometime previous to 1873. In 1887 it was found in the East, and since that 10 THE SAN JOSE SCALE. time it has spread, principally through the transportation of nursery stock, over a large part of the United States. Pages 20 and 21. The first intimation of its presence in Rhode Island was gotten in 1897. It is probable that it was intro- duced into the State a few years previous to that time. It is now found in ever}^ town in the State, and in a large majority of the orchards. Pages 21 and 22. When only a few of the San Jose scale are present, the insect is difficult to detect. When a tree or shrub be- comes thoroughly infested, the scale forms a grayish, scurfy coating on the bark. On rubbing the bark vigor- ously, a yellowish liquid appears, due to the crushing of the insects underneath the scale. On young, green wood, and on light or green-colored fruit, a reddish dis- coloration can be seen around each scale. A small, low-priced magnifying glass is of great aid in detecting the insect. Pages 22 and 23. The San Jose scale survives the winter in the larval stage, and matures in the early spring. Unlike most of the insects that we are acquainted with, the San Jose scale does not lay eggs, but produces its young alive. The period of bearing young extends, for each female, over five or six weeks, and a total of from three to four hundred are produced. The young larva remains active for about a day and a half, after which it settles down and begins to secrete over itself the scale covering. The females never move again, but the males when mature appear as minute, two-winged, fly-like insects. The San Jose scale insect matures in about forty-five THE SAN JOSE SCALE. 11 days from birth, and we have here in the North from three to four generations. Pages 23 to 26. The host plants of the San Jose scale include a large nimiber of the trees and shrubs usually grown in nur- series. Pages 27 to 31. The enemies of the San Jose scale include a number of very minute, parasitic-insect enemies, and the well-known ladybird beetles. Pages 32 to 34. The San Jose scale is distributed largely by means of nursery stock. For short distances it may be carried by the wind, insects, birds, and even higher animals. It may spread from tree to tree by interlacing branches. Page 34. The loss due to the scale in the State of Rhode Island amounts, at a conservative estimate, to over two hundred thousand dollars. Pages 35 to 38. The San Jose scale is changing the fruit-growing of the State. Small growers are becoming discouraged, and only those who are taking up a fight against the scale in an energetic manner have faith in the future of fruit- growing. Pages 38 to 40. Fruit-growing is gravitating into the hands of special- ists. A higher class of fruit and better prices will be the rule in the future. Page 40. The chances of saving a tree badly infested with the San Jose scale depend upon its vitality primarily, but also on the determination of the grower to continue fighting the scale. Page 41. The law of supply and demand will so regulate the 12 THE SAN JOSE SCALE. price of fruit that it will cover the* additional cost of spraying. Pages 41 and 42. The present means of controlling the San Jose scale may be divided into two classes: First, preventive or general orchard treatment. Plant stock free from scale; keep it in a thrifty condition; and plant and prune so as to make the labor of subsequent spraying economical. Pages 42 to 44. Second, spraying. Spray thoroughly in early spring or late fall with an effective solution. Trees badly infested should be spraj^ed both spring and fall. The standard remedy to-day is the lime-sulfur wash, made up as follows: Lime, fresh, unslaked 15-20 lbs. Sulfur 15 lbs. Water 50 gals. Slake the lime with hot water enough to keep it well covered. Make the sulfur into a thin paste with a small quantity of hot water, and add to the lime while slaking. Stir thoroughly, and when slaking ceases, add water to make 20 or 25 gallons. Boil from 45 minutes to one hour in a kettle, or by means of steam. Strain through a wire sieve of 20 meshes to the inch into spray barrel or tank, and add water to make 50 gallons. Apply at once. Pages 44 to 56. Excellent remedies are obtained from petroleum. Miscible, or so-called ''Soluble" oils, either home-made or some of the well-prepared proprietary brands, are ef- fective and can be recommended for those who can not use the home-made lime-sulfur wash. Pages 56 to 60. THE SAN JOSE SCALE. 13 A discussion of the comparative value of the lime-sul- fur and miscible oils is given on pages 60 and 61, and a few other spray solutions used for the San Jose scale are mentioned on pages 61 and 62. The time of the year to spray depends a little on the extent of the infestation and on the solution used, but principally on the convenience of the orchardist. Gen- erally speaking, it should be given just after the leaves have fallen in the autumn, or just after they come out in the spring. (The one absolutely important considera- tion in applying a spray remedy against the scale is thoroughness.) A good spray outfit, suitable to the kind and amount of spraying to be done should be secured. The essentials are a good pump, sufficient length of hose, an extension rod, and a good nozzle of the Vermorel type. Pages 65 to 73. Fumigation with hydrocyanic-acid gas is useful under some conditions. As an orchard remedy it is of little value in the East.. Pages 74 to 77. As a preventive of distribution of the scale through nursery stock, fumigation is worthy of careful considera- tion. Pages 77 to 83. As a remedy for the San Jose scale in greenhouses, hydrocyanic-acid gas is practically a specific. Pages 83 to 87. The dipping of nursery stock is being recommended as a substitute for fumigation, and is worthy of trial. Pages 87 and 88. INTRODUCTION. During the last few years a careful study of injurious insects has brought out the not very pleasant, yet interesting, fact that they take an enormous toll from the annual production of crops in the United States. Dr. Marlatt, in a recent paper in one of the yearbooks of the Department of Agriculture, estimated that the annual loss to growing farm crops alone, due to insect depredation, amounts to about 10 per cent, of the total value of these crops. For the year in which the paper was written, the total loss due to insect injury was about five hundred millions of dollars. If we add to this the loss to forest crops and products of all kinds in storage, there was for that year a grand total of between seven hundred and fifty and eight hundred millions of dollars. And yet this does not include the total loss due to insects, for we have learned that they enter into our interests in various ways which were not known or suspected until recent times. Take, for instance, the carrying of disease by insects which results in loss of health, productive capacity, and attendant expenses, to say nothing about the frequent loss of human life. The only reason why farmers have submitted to their part of the heavy tax without complaint, except when the enormous increase of some particular species of insect has caused an uncommonly large or total destruction of crops, is: first, that they have not always realized its enormity, the levy being generally made before the crop is har- vested and measured; second, the comparative familiarity with loss due to insects and the consequent indifference; and third, the idea that the loss is more or less inevitable and must be accepted as a matter of course. A study of our injurious insects has further revealed the fact that THE SAN JOSE SCALE. 15 a large percentage of our worst pests are foreigners, and have gained entrance to our country through the avenues of transportation in one way or another. In a recent exhibition of the Department of Agri- culture at the World's Columbian Exposition, as described by Dr. Howard in the Yearbook for 1897, 602 different species of insects, 171 of which were imported species, were shown as being more or less injurious to agricultural products. From this group were again separated out 73 which were especially injurious, and of these 30 were native, 37 imported, and 6 of doubtful origin. Among the imported ones may be mentioned the San Jose scale, gypsy moth, brown-tail moth, elm-leaf beetle, codling moth, cabbage worm, cotton boll weevil, oyster-shell scale, pea weevil, buffalo moth, leopard moth, asparagus beetles, and Mediterranean flour moth. Once in this country and acclimated, which most of them become in a comparatively short time, they have found an abundant food supply and more or less freedom from the parasitic and predaceous enemies which harassed and kept them in check in their native habitats. Insects have enormous reproductive powers, and with the natural checks removed, these introduced pests have increased at an alarming rate in the case of some species, and have spread consternation in the ranks of many people who grow the crops on which these insects feed. It is well to remember that we have not as yet all the injurious in- sects of foreign countries which are liable to be imported. Dr. Howard, in the article already quoted, describes a number of in- jurious insects from Europe, Australia, West Indies, Mexico, and other countries, which are liable to be imported at any time, and which are injurious to species of fruit raised in the United States. A national quarantine law similar to that now carried out by the State of California, through which a thorough inspection can be made of all plants and material which are liable to bring these insects into our country, is an immediate necessity. It has been recommended to Congress on several occasions by Dr. Howard and others, but so 16 THE SAN JOSE SCALE. far no steps have been taken to pass such a law. The only thing that can be done at the present time is for the inspectors of the dif- ferent maritime States to keep a sharp lookout for importations of plants; and nurserymen and others who order from foreign countries can help materially by notifying the inspectors of the arrival of con- signments of such plants in order that inspections may be made if' necessary. Many of the introduced insect pests just mentioned have created great havoc locally in many parts of the country, but there is per- haps no insect which has gained such wide-spread distribution throughout the whole country, and caused such large losses generally, as the San Jos6 scale. On account of its wide dissemination and detrimental work, there is an enormous amount of published infor- mation available regarding the pest, but much of this literature is of little or no interest to the average grower. Nevertheless, in order to intelligently take up the problem of dealing with the insect, he should have a thorough knowledge of its life history and the various methods of fighting it, together with the reasons for the various recommendations. This part of the bulletin will, therefore, be de- voted to presenting this information as briefly and plainly as pos- sible. There is also a little information in regard to the history of the San Jose scale in this country; the struggles which have been going on against it in the different sections, and especially in this State; its present status and the prospects for the future, which will be of some value in itself to the average citizen interested in the presence of the scale as an economic problem, and also as throwing light on the importance to the agriculturist of being on the lookout to prevent the introduction and dissemination of other pests which, fortunately, have not as yet reached our country. Popular Fallacies Regarding Insects and their Control. Not knowing the life history or character of insects, many suppose that a spray good for one kind will also be efficient for others. Hav- ing learned that certain stomach poisons, such as, Paris green, ar- THE SAN JOSE SCALE. 17 senate of lead, etc., are effective against potato bugs, they are sur- prised to find out that these are of absolutely no use for the San Jose scale. Still others show less knowledge of the principles of spraying in believing that any spray solution, as for example, Bordeaux mix- ture, should be good for the whole category of plant ills. It can not be emphasized too strongly that insects must be treated in a different way from plant diseases, and also that the species of these two classes of plant enemies vary greatly in their habits and life history, and a thorough knowledge of each is necessary in order to work intelligently in destroying or controlling them. It is of special importance to the modern farmer to know that insects may be divided into two classes, according to the manner in which they take their food: 1. Those which chew the leaves or other parts of the plant. 2. Those which insert a beak or tube into the tissues of the plant and suck up its juices. Prominent examples of the former are various injurious beetles, such as, the potato and rose beetles, popularly termed "bugs," and their larvse, and the caterpillars of the various butter- flies and moths, such as, the cabbage butterfly, the mourning cloak butterfly, and the gypsy and brown-tail moths. As an example of the latter may be mentioned the true bugs, to which belong plant lice, scale insects, the squash bug, etc. The former can be quite readily reached in many cases with some form of stomach poison put upon the outside of the leaves or other parts of the plant on which they feed, but it is evident that the latter class, since they absorb all their food from the interior of the plant, can not be reached by any such application of poisons. It may also be added, although it is very much to be regretted that it should be neces- sary, that neither this class of insects nor any kind of an insect which feeds upon plant tissues can be discouraged or destroyed by any magical process of inserting or injecting chemicals into any part of the plant, or by spreading them in or on the soil for absorption by the roots. The reasons for this are self-evident on even casual reflection. The plant would be unable to take up any appreciable 18 THE SAN JOSE SCALE. amount of such chemicals. If taken up, the distribution thereof would be extremely local and weakened by dilution with large quantities of sap; and finally, should such nostrums be absorbed in sufficient quantity to poison the insect, the plant itself would be poisoned and destroyed. Coming back to a more specific consideration of the San Jos6 scale, we frequently hear of other remedies and processes of treatment which are more rational but nevertheless faulty in their composition or application, or both. For example: Common whitewash is ap- plied by a great many to the trunk and branches of the trees with the mistaken idea that it is an efficient remedy against the scale. The application of this is faulty for two reasons: In the first place it is not sufficiently strong to destroy any but possibly the young ^nd only partially protected scale; and secondly, because its appli- "Cation on the trunks and large branches only protects those parts of the tree, the infestation of which is in reality of much less importance than the infestation of the smaller branches and twigs. Another objection to this method — and it is true of the application of any :Solution, whatever it may be — is that no remedy against the San Jose ;scale can be put on with a paint brush or wash rag, unless the tree IS very small or pruned back to the trunk and a few stubs of branches, without the application of so much labor that the cost of application will greatly exceed the value of the tree. The grower must pro- vide himself with adequate and up-to-date apparatus suited in size to the number of trees which he will have to spray. The Twentieth Century agriculture can not succeed with antiquated methods and appliances. Mechanical means, such as scraping the trunk and larger branches, are sometimes resorted to, but for reasons already given, such remedies are of little use. If the tree is an old one with very rough bark, scraping off the loose portions which may hide the scale under- neath is valuable as preparation for subsequent thorough spraying. The only mechanical remedy which is at all efficient is the appli- cation of a sharp axe to the trunk of the tree close to the ground. To THE SAN JOSE SCALE. 19 those who can not or will not have their trees thoroughly treated, it is undoubtedly the only remedy when the trees have become thor- oughly infested, for so far, we have not come across a single case in the State where the scale, when once established, has ceased its work until after the tree has been destroyed, unless intelligently treated with some effective scale remedv. THE SAN JOSE SCALE. (Pronounced San Ho-say.) Aspidiotus perniciosus, Comst. General History. This insect was first discovered in this country in Cahfornia in 1873, The term San Jose scale is derived from the valley of that name where it was first located. It must have been prevalent some- time previous to the year mentioned, as it was then well distributed in the section where it was found. Fio. 3.— Male San Jose scale insect, greatly enlarged, after Howard, U. S. Dept. of Agr., Bur. of Ento., Bui. 62. The first description of the insect was written by Professor Com- stock in 1880. In recognition of its capacity for serious mischief be called it Aspidiotus perniciosus. The Pernicious Scale has been sug- THE SAN JOSE SCALE. 21 gested as a common name but has not been generally accepted, and it is doubtful if another name, "The Chinese Scale/' proposed by the Department of Agriculture will displace the one by which it has been known for so many years. There has been a great deal of speculation as to where this insect originated. It was successively reported as having been introduced from Chili, Hawaiian Islands, Australia, and Japan; but recent in- vestigations by Dr. Marlatt of Washington seem to prove quite con- clusively that the original home of the San Jose scale is in China. In the East the scale was first discovered in the grounds of Dr. C. H. Hedges of Charlotte ville, Virginia, in 1893. The infestation was investigated, and the introduction was quite definitely traced to two New Jersey nurseries, which in 1886 or 1887, in an endeaver to se- cure a curculio-proof plum, had imported a number of plum trees from the San Jose district in California. These nurseries, probably without knowing what a serious pest they were distributing, scattered it broadcast in various localities in the Eastern United States. It soon got into other nurseries, and at the time of its discovery in 1893, as subsequent investigation proved, it had become established in a large number of different places in the various states. Since then, and until the inspection laws became generally enacted in the •different states, while some of the nurseries took pains to send out only clean stock, the scale was still further disseminated into almost every state in the Union by ignorant or irresponsible nurserymen and others dealing in shrubs and trees liable to be infested. Recent legislation has put a partial check upon the continued ■distribution, but the scale has now been so far scattered that all hope of ever exterminating it has gone, and all that can be done is to •check its ravages and reduce the damage from it to a minimum. History in Rhode Island. It is difficult to trace definitely the history of the scale in Rhode Island. Professor Marlatt, in Bulletin 62 of the Bureau of Ento- mology, Department of Agriculture at Washington, states that 22 THE SAN JOSE SCALE. up to 1898 no report of the presence of the scale had come from this State, In a bulletin by the State Board of Agriculture, written by Mr, Southwick in 1900, the author speaks of it as being of re- cent importation. It is probable, however, that it was known to be present as early as 1897, and to have been established sometime previous to this year. Professor Adams of the Rhode Island Col- lege states it as his recollection that the first report of the presence of the scale came to this institution from Newport in 1897, and that another was sent in soon thereafter from an estate near East Green- wich, Beginning with 1898 a large number of reports and also infested material were received at the college from various parts of the State, It was undoubtedly thoroughly established in some of the larger nurseries of the State at this time, as many growers are quite unanimous in their statements that trees which they pur- chased from certain nurseries near Providence from 1898 to 1900 were destroyed two or three years later by what proved to be the San Jose scale. At the present time there is not a single town in the State but what is infested in one or more localities, and no plantations in which nursery stock has been set out within the last ten years are likely to be free from the pest. It is probable that four-fifths of the orchards of the State are more or less infested, and in many places the majority of the trees have been so badly injured as to necessitate their destruction. Methods of Detecting the Scale. When a tree or shrub first becomes infested and there are only a few scales present, detection is extremely difficult even for the experienced entomologist. To those inexperi- enced in the use of the magnifying glass, detection is more or less F.a.4.-Magnifying Glass. ^.^^^^^ ^^^.^ ^^^ ^^.^^ beCOmeS quite thoroughly infested, at least in places. Close observers will THE SAN JOSE SCALE. 23 probably notice quite readily with their naked eyes the bright yellow little insects which crawl around throughout the summer- time and autumn until frosts set in. The light-colored scales about the diameter of a common pin which have just settled down, as well as somewhat larger and darker scales about the size of a small pinhead, may perhaps also be observed against the smooth bark on young wood. When the bark becomes quite thoroughly covered with the scales it assumes a rather rough, scurfy appearance of an ashy-gray color. When rubbed with the hand, or, better, with the thumb nail, a yellowish liquid appears, due to the crushing of hun- dreds of insects. This liquid gives a greasy feeling to the bark where it has been rubbed. On ver}^ young wood, especially if of a bright, greenish color, the scale will be surrounded by a reddish discoloration. This is true also on fruit, and of course it shows best on green fruit and on light-colored varieties. Care must be used, however, not to confuse the red spots formed by fungous diseases, such as Entomosporium maculatum, with those of the scale. If the outer bark, even though dark and showing no discolora- tion, be stripped off so as to disclose the inner green-colored portion, this will also be found discolored in the same way as described above, if the scale is present. The orchardist should by all means possess and learn to use a small magnifying glass. It will help him greatly in detecting the scale. Such a one as illustrated in Figure 4 can be purchased for about fifty cents, and for all practical purposes is as good as one costing ten times this amount. Life History. Unlike the larger insects with which we are more familiar, the scale is ovoviviparous, that is, the young are born alive instead of developing in eggs laid by the parent. The young larvae crawl about from twenty-four to thirty hours after birth until they find some suitable place to settle down. They then proceed to insert the long sucking tube into the bark, and a waxy secretion is exuded, 24 THE SAN JOSE SCALE. Fig. 5.— Underside of female scale insect, showing proboscis or sucking tube. Greatly en- larged. After Howard, U. S. Dept. of Agr., Bur. of Entc, Bui. 62. from the back of the insect, which in time gradually covers the whole insect and hardens into the scale. Soon after settling down the larva loses its legs and antennae, and in the case of a female the insect becomes fixed and never moves from its position. The larva sheds its skin several times, and this is added to the scale covering. In about thirty days the female becomes full-grown, and in a week or so thereafter begins to bring forth young. She continues to give birth to young at the rate of nine or ten a day for about six or seven weeks. The male scale attains maturity in about the same length of time as the female. Owing to the fact that young are being born- over such a long space of time from each female, it is difficirit to ascertain the num- ber of generations; but according to the majority of investigators, there are three or four in the North. Four hundred young is an average for each female, and the possible number of descendents for one over-wintering female is enormous and has been estimated at over three billions. The scale winters over in the larval stage. Insects in all stages. THE SAN JOSE SCALE. 25 Fig. 6.— Development of the scale, a— Underside of larvse showing proboscis. 6— Back of larva with wax exuding, c— Further development of wax secretion, rf— Larval scale nearly formed. After Howard and Marlatt, U. S. Dept. of Agr., Bur. of Ento., Bui. 62. of development, from the active crawling larvae to the adults which have completed their life history, may be found on the tree at the beginning of winter, but probably only those larvae which have a well developed scale survive. Probably not over one-eight to one- third survive the winters of the north. Description of the San Jose Scale. The San Jose scale, As- pidiotus perniciosus, Comst., belongs to the class termed ''Armored Scales." In this class the scale covering is in the nature of a house for the insect, and does not form a part of its body. Fig. 7.— Scale of male San Jose. Greatly enlarged. After Atwood. 26 THE SAN JOSE SCALE. The adult female scale is about ^ of an inch in diameter and nearly circular in outline. At or near the center of the scale is the highest point, or nipple, usually of a darker color than the rest, and this is surrounded by a concentric depressed area. Outside of this Fig. 8.— Cut showing characteristic form of anal plate of female, as seen under the micro- scope. After Howard, U. S. Dept. of Agr., Bur. of Ento., Bui 62. depression the scale is marked off more or less distinctly into rings or circular areas, some of which may have a slightly lighter j^ellow- ish shade than the central nipple or the margin of the scale. In color the scale varies from white or light yellow when 5'^oung to dark gray or almost black when it approaches maturity. See Figs. 1 and 6. The male scales are smaller, more elongated or oval in shape, and flattened at the extremities, with the nipple near one end. The con- centric rings are more plainly marked than in the female. See Fig. 7. The young larvse of both sexes are ovoid in shape and yellow in color. They have six legs, two antennae or feelers, and a long proboscis or sucking tube folded beneath the body. After the first moult, the larvse of both sexes lose their legs and antennae. The female becomes more or less shapeless and resembles a flattened sack, somewhat rounded in outline. See Fig. 5. It remains fixed and changes but little in succeeding moults, while the male goes through a number of changes, finally acquiring six legs and antennae again, and two wings, and backs out from under the scale as a. minute, active, fly-like insect. See Fig. 3. HOST PLANTS. P HE following list of host plants of the San Jose scale has been copied from a list by Dr. W. E, Britton, quoted in Bulletin No. 62 of the Department of Agriculture at Washington, In this list we mention only the trees and shrubs which have been observed in this State. It" will be noted also that the list varies a little from that of Dr. Britton's, in that a few plants which are mentioned as "Commonly or Badly Infested" have not been found so in the investigation in this State. In a like manner, a few that are noted in the original list as "Seldom or Never Infested" have been found quite badly infested in our inspection work: Commonly or Badly Infested. Amelanchier canadensis. Medic. Shad-bush, Juneberry. Cornus sanguinea. Linn. Red osier. Red-twigged dogwood. Cratoegus oxyacantha. Linn. EngUsh hawthorn. Crataegus coccinea. Linn. Scarlet fruited hawthorn. Cratcegus crus-galli. Linn. Cockspur thorn. Cydonia vulgaris. Pers. Common quince. Cydonia japonica. Pers. Japanese or flowering quince. Populus deltoides. Marsh. Carolina poplar. « Populus nigra. Linn, var italica Du Rot. Lombardy poplar. Prunus avium. Linn. Sweet cherry. Prunus cerasifera. Ehrh. var. atropurpurea. Dipp. (P. pissardi.) Purple- leaved plum. Prunus domestica. Linn. European plum. Prunus japonica. Thunb. Flowering almond. Prunus persica. Sieb. & Zucc. Peach. Prunus triflora. Roxbg. Japanese plum. Prunus virginiana. Linn. Chokecherry. Pyrus communis. Linn. Pear. Pyrus malus. Linn. Apple. 28 THE SAN JOSE SCALE, Pyrus. Sp. Crab apple. Ribes oxyacanthoides. Linn Gooseberry. Ribes aureum. Pursh. Missouri or flowering currant. Ribes rubrum. Linn. Currant. Rosa. Sp. Rosa rugosa. Thunb. Japanese Rose. Salix. Sp. Willow. Salix -pentandra. Linn. Laurel-leaved willow. Salix babylonica. Linn. Weeping willow. Sorbus americana. Marsh. American mountain ash. Sorbus axicMparia. Linn. European mountain ash. Symphoricarpos racemosus. Michx. Snowberry. Syringa vulgaris. Linn. Common lilac. Tilia americana. Linn. American linden or basswood. Ulmus americana. Linn. American elm. Ulmus campestris. Smith. English or European elm. The following, mentioned in Dr. Britton's list as being "Commonly or Badly Infested" have not been found so in our investigation work, even when standing among fruit trees which have been "cov- ered with the scale: Akebia quinata. Decaisne. Cratcegus cordata. Soland. Washington thorn. Fagus sylvatica. Linn. var. purpurea Ait. European purple-leaved beech. Juglans sieboldiana. Maxim. Japanese walnut. Liguslrum vulgare. Linn. Common privet. Prunus serotina. Ehrh. Wild black cherry. Pyrus sinensis Lindl. Sand pear, including Kieffer, and Le Conte pears. Ribes nigrum. Linn. Black currant. Syringa persica. Linn. Persian lilac. The following, mentioned under the next heading of the above- mentioned list as being rarely infested, have been found quite sub- ject to the scale: Elceagnus longipes. Gray. Silver thorn. Rhus cotinus. Linn. Smoke bush. Staphylea sp. Bladder nut, which is mentioned in Dr. Britton's THE SAN JOSE SCALE. 29 list as being found free from the scale, has been found badly in- fested in one of our nurseries. Occasionally or Rarely Infested. Acer saccharinum. Linn. Silver maple. Acer saccharinum. Weir'.s cut-leaved. Acer platanoides. Linn. Norway maple. Alnus. Sp. Alder. Cornus stolonifera. Michx. Wild red osier. Cornus florida. Linn. Flowering dogwood. Deutzia. Sp. Euonymus. Sp. Forsythia. Sp. Hibiscus syriacus. Linn. Shrubby althea. Morus alba. Sp. Mulberrj' . Prunus cerasus. Linn. Sour cherry. Rhodotypos kerrioides. Sieb. & Zucc. Rubus strigosus. Michx. Red raspberry. Sambucus. Sp. Elder. Viburnum opulus. Linn. Cranberry tree. Vitis. Sp. Grapes. Msculus hippocastanum Linn. Horse-chestnut, which is given here in the original list, has often been found among trees badly infested, and yet at no time have we discovered any San Jos6 scale on it. The following also have never been found infested, although it should be said in regard to them that they have not been suffi- ciently observed by the writer to place them definitely in the immune list in this State: Ampelopsis quinquefolia. Michx. Virginia creeper. Betula alba. Linn. Cut-leaved white birch. Buxus. Sp. Box. Castanea americana. Raf. Chestnut. Catalpa bignonioides. Walt. Common catalpa. Celtis occidentalis. Linn. American blackberry. Fraxinus americana. Linn. White ash. Gleditschia triacanthos. Linn. Honey locust. 30 THE SAN JOSE SCALE. Juglans nigra. Linn. Black walnut. Kalmia latifolia. Linn. Mountain laurel. Ligustrum ovalifolium. Hassk. California privet. Lonicera. Sp. Honeysuckle. Picea alba. Link. White spruce. Robinia. Sp. Locust. Rubus nigrobaccus. Bailey. {R. villosus.) Common blackberry. Sassafras ofjidnale. Nees. Sassafras. Spiraea. Sp. Thuya occidentalis. Linn. American arbor vitae. Not Infested. Ailanthus glandulosa. Desf. Tree of Heaven. Andromeda. Sp. Aralia spinosa. Linn. Hercules' club. Bignonia. Sp. Trumpet vine. Calycanthus floridus. Linn. Carolina allspice, sweet-scented shrub. Carpinus. Sp. Hornbeam. Cedrus. Sp. Cedar. Cephalanthus occidentalis. Linn. Buttonbush. Clethra alnifolia. Linn. Sweep pepper bush. Corylus. Sp. Filbert,, hazelnut. Exochorda grandiflora. Lindl. Pearlbush. Gaylussacia. Sp. Huckleberry. Genista tinctoria. Lirm. Dyer's greenweed. Ginkgo biloba. Linn. Maidenhair tree. Gymnocladus canadensis. Lam. Kentucky coffee tree. Hamamelis virginiana. Linn. Witch-hazel. Hedera heli.c. Linn. English ivy. Hicoria. Sp. Hickory. Hydrangea (all species). Juglans cinerea. Linn. Butternut. Juniperus. Sp. Juniper. Laburnum vvlgare. Griseb. Golden chain. Larix. Sp. Larch. Liquidambar styraciflua. Linn. Sweet guni. Liriodendron tulipifera. Linn. Tulip tree. Magnolia {all species). Myrica cerifera. Linn. Wax myrtle. THE SAN JOSE SCALE. 31 Nyssa syLvatica. March. Tupelo, pepperidge, black gum, sour gum. Qstrya virginica. Wild. Hornbeam, iron wood. Philadelphus coronariiis. Linn. Mock orange, syringa. Pinus. Sp. Pine. Platanus occidenialis. Linn. American plane, buttonwood. Quercus {all species). Oak. Retinispora {all species). Japan cypress. Rhamnus. Sp. Buckthorn. Rhododendron. Sp. Sciadopitys verticillata. Sieb. & Zucc. Umbrella pine. Shcpherdia. Sp. Smilax, Sp. Sophora japonica Linn. Japan pagoda tree. Stephanandra ftexuosa. Sieb. & Zucc. Tamarix. Sp. Tsuga canadensis. Carr. Common hemlock. Vaccinium. Sp. Wistaria. Sp. Xanthoceras sorbifolia.^\Bunge. NATURAL ENEMIES Of THE SAN JOSE SCALE. Dr. L. 0. Howard of the Department of Agriculture, in a recent bulletin by Dr. C. L. Marlatt, states that there are eight species of true parasitic insects which have been reared from the San Jos6 scale. These are nearly all very minute parasites which live on their host insect underneath its scale. Fig. 9. — Mlcroweisiamisella preying on San Jos^ scale, a— Adult beetle. 6— Larya. c— Pupa natural size is indicated by short line near each figure, d— Calyx end of apple, showing beetles and larvae destroying the San Jose scale, also greatly enlarged. After Howard and Marlatt,U. S. Dept. of Agr., Bur. of Ento., Bui. 62. It will hardly be of interest to the readers of this bulletin to give a very full resume of Dr. Howard's account of these parasitic in- sects. They are not primarily San Jose scale parasites, but live also on other armored scales. The writer has in a few cases picked up scale-infested twigs which unquestionably showed the work of some of these little parasites, but it THE SAN JOSE SCALE. 33 is needless to say that, so far, they are not even materially checking the pest. Rather more hope of relief is experienced from larger so-called predaceous insect enemies, chief among which are the various lady- bird beetles. These are well-known predaceous enemies of plant lice, and it is known definitely that two of the species, common in the State, are feeding to some extent, at least, on the San Jos6 scale. One of these is the Twice-stabbed ladybird, Chilocorus hivulnerus, Muls. This is a little black, sluggish, hemispherical beetle with a bright red, or yellowish-red spot on each of the wing covers. It is about ^ of an inch in length. In no case has this been found in very large 'numbers. Even on badly infested trees the writer has seldom seen more than four or five specimens. The other IsLdyhird, Microweisia misella, Lee, from which we may expect a great deal more help, is very much smaller, only about ^ of an inch in length, similar in shape to the former, but coal-black in color. In a few cases the writer has observed these little beetles in very large numbers on scale-infested trees. The numbers of the scale, however, were so great that even though numerous, the beetles were scarcely able to appreciably check the pest. On the discovery of the fact that the scale came originally from China, it was hoped that parasites from its native habitat might be introduced, and the Department of Agriculture imported a lady- bird, Chilocorus similis, which is said to be its principal enemy in that country. This is a black beetle which, in its adult form, is practically indentical in shape and color with the twice-stabbed lady- bird. It differs from our own species, however, in its larval stage, and also to some extent in its life' history. It has failed to become sufficiently acclimated to establish itself in this country, except in a very few places, and even in these places, it is scarcely multi- plying sufficiently to keep the scale in check. In time, however, this species may possibly establish itself more fully in some parts of the country, and perhaps also some of our native species will develop a larger appetite for the San Jose scale. It is possible, too, 34 THE SAN JOSE SCALE. that many of the parasitic enemies to which we have made brief reference may become more active in future years. A few fungous and other diseases which affect the scale have been studied by the Department of Agriculture and some of the experi- ment stations, and under favorable conditions some of them may render valuable assistance in checking the pests in sections of the country favorable to their growth. Means of Distribution of the Scale. Owing to the fact that the young female moves around for a very brief time and can travel only a short distance, after which it settles down never to move again, the scale can not be distributed very widely or rapidly through its own efforts. Within a very restricted radius it is undoubtedly spread slowly through the aid of other in- sects. The ladybird beetles, which have been spoken of as preda- ■ceous enemies of the scale, are no doubt occasionally responsible for its dissemination, as observers have frequently noted beetles of this kind with young scale larvae upon them. Higher animals, such as, birds, squirrels, etc., probably distribute a few. In orchards, horses in cultivating or men in pruning and harvesting may aid in its distribution. The wind is perhaps responsible for carrying it short distances, and in close plantings, interlacing branches per- mit distribution from tree to tree. The chief means of distribu- tion, however, to which we owe the very rapid spread throughout this country from state to state, and from one locality to another within the states, is through the transportation of nursery stock in its various forms, such as, cuttings, buds, scions, and young trees. It is deeply to be regretted that our country did not wake up to the danger of dissemination in this way when it was first discovered and pass the inspection laws which we now have to prevent its spread. THE SAN JOSE SCALE. 35 Losses Due to the Scale in Rhode Island. Last summer an arrangement was made with the Department of Agriculture at Washington wherebj^ it was made possible to carry on a special investigation in the ravages of the scale for this section of the country. A large number of circular letters were sent out with request for information regarding the number of fruit trees of different kinds destroyed or injured, and also certain questions regarding the distribution of the scale and proposed methods of treating it. The results did not come up to our expectations. About seven thousand circulars were sent out and only about 550 have been received at the present time. It made it impossible to determine very accurately what the complete loss is for the whole State, but enough has been ascertained to give us some basis for further cal- culation. The replies gave us a great deal of information regarding the present situation in the State, but as this is discussed elsewhere, it will not be necessary to repeat it here. The blank sent out re- quested information regarding the number of trees of different kinds and ages which had been destroyed or injured by the scale. It also requested that the recipients in returning the blanks should place an estimate on the value of the trees. The latter request was complied with only in very few cases, and it was therefore necessary to secure estimates in other ways. Such estimates have been very kindly furnished by a number of fruit growers and hor- ticulturists in this and other states, and it is on these estimates that we base the calculations which will be given below. It may be said in passing that the estimates varied greatly; the value of a mature apple tree, for instance, being placed at all the way from $25 to S250. The figures which we shall use are much lower than the average value as calculated from the estimates that have been received. They are undoubtedly still too large for the average con- 36 THE SAN JOSE SCALE. ditions in this State, and the sum total of loss as derived from them has been still further reduced to one-third. Apples* 1 year $1 00 2 and 3 years 2 00 4 and 5 years 3 00 6 and 7 years 4 00 8 and 9 years 6 00 10 and ] 1 years 8 00 12 and 13 years , 10 00 14 and 15 years 12 00 16 and 17 years 15 00 18 and 19 years 18 00 20 and 21 years 22 00 22 years 25 00 26 years 30 00 30 years 40 00 35 years 50 00 40 years 50 00 45 to 60 years 50 00 75 years 20 00 An injured tree was valued at one-half of what an uninfested tree was worth. According to the reports received: — The total number of apples of all ages injured was 4,370 The total number of apples of all ages destroyed was 1,421 The total loss was approximately S60,300. Reducing this by two-thirds, gives us a total loss of $20,100, There are in the State approximately six thousand farms, and if we assume that one-half of these have apple orchards, the num- ber of reports is only one-sixth of the total number of farms. It should be reasonably fair, therefore, to multiply the $20,100 loss above noted by six to get the total value for the State. This w^ould place the loss at $120,600. This sum does not take into consideration ♦Age given is time after permanent planting and does not include the time that the tree hasi grown in the nursery. THE SAN JOSE SCALE. 37 the loss to the small grower in village and city. If such losses were counted it would probably raise the total to $160,000 or $170,000. To get at the proportion of loss to the total value of the orchards of the State, the number of bushels of apples in 1889 and 1899, as given by the census of 1900, were added together and divided by two to get the average for the two years. This amounts to 289,401 bushels as the product of the farms of the State. Multiplying 25 cents, which should not be too high a price as the net return per bushel during the last five or six years, by the above number will give us $72,350.25 as the net income from the apple trees of the farms in the State. Assuming this to be 5 per cent, interest on the value of the apple orchards, their total value would be $361,751.25. This would indicate, then, that the loss to the apple orchards of the State amounts to about one-third of their total value. The loss to pears, peaches, and plums, according to the re- ports received and calculated from estimates of value similar to those obtained for apples, amounts to: Pears, killed, 839 trees $8,492 70 Pears, injured, 855 trees 6,669 75 Peaches, killed) 6,484 trees 24,143 50 Peaches, injured, 667 trees 1,794 00 Plums, killed, 616 trees 1,682 25 Plums, injured, 433 trees • 915 33 $43,697 53 Assuming that the estimate here, also, being for trees reason- ably well cared for, would be too high as an average for the State, and taking only one-third of the total loss, we have $14,565.84. Orchards of these trees are not as common, of course, as apples, and it would not be fair relatively to estimate that one-half of the farms in the State have such orchards. Assuming, however, that they are found on one-third, or approximately 2,000 of the farms, the reports which have been returned are one-fourth of the total number of possible reports. Multiplying the sum which we have 38 THE SAN JOSE SCALE. estimated to be the loss by four, we have a total loss of $58,263.36,. which, when added to the loss in the apple orchards, gives a totaf loss of $178,863.52 for the orchards of the State. As with apples, many plantations of the last-named fruits are not enumerated as farms, and if we add the loss to that of apples outside of farms and this sum to the total just given, we shall have a grand total of over $200,000 as a conservative estimate of the loss to the apple,, pear, peach, and plum plantations for the last six or seven years. But this is not all. If loss to other trees and to shrubs which are attacked by the scale be added, the grand total will be still greater. These figures are, of course, only approximations, but it is probable that the loss is rather underestimated than overestimated. To these direct losses should also be added the loss from mis- directed labor in spraying, the waste of spraying materials, and the interest on the reduction in incomes from the farms due to the- destruction of the orchards. The Status of Fruit-Growing as Affected by the San Jose Scale. Fruit-tree planting, generally speaking, is at a standstill. Old- orchards are gradually disappearing, and the very lucrative business- of growing orchard crops, to which some of our lands are eminently suited, is fast being destroyed, except in the case of a few up-to- date growers who have looked the San Jose scale problem squarely in the face, studied the situation, secured what information they could from colleges, experiment stations, and agricultural publica- tions generally, in regard to the best methods of overcoming the difficulty, and have then set to work with a grim determination to "do or die." Such men are succeeding, and with the gradual de- cline of fruit-raising among their fellow growers, they are reaping a well-merited reward in greater demands for their fruit and higher prices. It is an oft-mentioned quotation from some horticultural lecturer,, that the scale is in reality a blessing in disguise, and that it is one of the greatest educators in fruit-growing. An uncharitable critic THE SAN JOSE SCALE. 39 would immediately say that this lecturer must be one of those who have profited by the higher price in fruit, but there is a deal of truth in the statement, however, looking at it as it stands. The old-fashioned method of planting trees and perhaps encouraging them a little by cultivation or mulching until they begin to bear, and then expecting them to produce abundant crops of good fruit from year to year is at an end. In fact, if the truth had been realized, part of this idea was exploded long ago, even before the advent of the scale, for the fruit grown by careless methods was not often of high quality. The first-class fruit of to-day was rare. The stand- ard of the markets was low, and people were willing to buy and use second-class fruit. Cider was more generally in demand, and a great deal of fruit could be utilized in its manufacture. People were also unaware that anything better could be expected from their trees. To these considerations in a small measure at least — and to the halo that always surrounds the good old times — and not en- tirely to the great increase in injurious insects and fungous dis- eases which usually receives all the blame — is due the fact that older people frequently say that fruit-raising has become impossible. In place of the old-fashioned way has come a closer study of orchard work and requirements of tree growth, and partial realiza- tion, at least, of the principles of plant nutrition and of the fact that the soil is not inexhaustible in plant food, even such as is re- quired by orchard crops. We no longer expect to gather crops of fruit, and sometimes hay or pasturage, from our orchards without adding something to feed the plants that we grow. Cultivation and fertilization for orchards are taken up precisely for the same reason that they are used for corn, potatoes, or garden crops. The scale has been an educator in many other ways. The at- tention which the orchardist has been compelled to focus upon it has been reflected partly also upon other insects which have existed only in limited numbers, or whose depredations were looked upon as so much a matter of course as to escape attention. Plant diseases have come into notice on account of their influ- 40 THE SAN JOSE SCALE. ence in checking the growth of plants or reducing the value of the crops harvested. Demand for information along these lines has grown rapidly. Agricultural colleges and experiment stations^ the National Department of Agriculture, and men in actual contact with fruit-growers and fruit-growing have been quick to study the crop pests, carry on experimental work, and supply much needed information, until we now have in America, if we are to believe an eminent British plant pathologist, the largest body of knowledge regarding spraying and related methods of dealing with injurious insects and plant diseases of any country in the world. Future Prospects. It is undoubtedly true that general fruit-growing in Rhode Island is on the decline, and many are predicting that the San Jose scale will reduce the total amount of fruit produced in the future. The latter statement is to be doubted. The hit-or-miss fi'uit-growing by everybody is undoubtedly approaching an end, but the large fruit-grower who will study the question closely and apply the knowl- edge gained will continue to increase his plantations. There will be an increase in the amount of high quality fruit and a decrease in that of poorer quality. The fruit growing, gravitating into the hands of specialists, will aid in maintaining a higher price for the products of the orchard, not only from the fact that there will be less competition, but also because there will be greater care taken in the growing and marketing of these products. The deplorable element in the present situation is the decadence of the home orchard. For a while, at least, the man who has a little land around his house will cease to plant fruit trees because it is too much trouble to keep them free from the scale. It is probable, however, that the small fruit-grower in village and city will learn some points in regard to spraying and care from the experience of the large orchardist. Dwarf trees offer a possible solution. By planting these he will be able to get quicker returns, keep the trees THE SAN JOSE SCALE. 41 near the ground where he can readily treat them, and still get as large returns of good apples as in the past. In the future better public spraying will be carried on by men who know their business and do the work in a careful manner at a price which the owner of the trees can afford to pay. Probably, also, the San Jos6 scale may be approaching the height of its virulence. It is the history of nearly every imported insect that it increases in activity and num- bers for some time after it is introduced, and then, as its enemies develop, it suffers a gradual decline until such a time as it shall have reached its proper balance in the economy of nature. Chances of Saving Trees Badly Infested. Whether to try to save a tree that is badly infested is sometimes hard to determine, except by giving it a trial. The question is, of course, can such a tree be revived into a healthy tree and brought into a bearing condition sooner than a new tree set in its place? Much depends upon the age of the tree and the kind of fruit. Generally we may say that if a tree shows vigor, as evinced by the shoots of the season, it will often revive at a surprisingly rapid rate when pruned back and thoroughly sprayed. If the main branches are dying, the young shoots weak, and especially if the bark on the trunk begins to show lack of life and vitality, the chances for saving the tree are very uncertain. The question of whether to attempt to save a tree also depends to some extent on the grower himself. It is useless to try to save a badly infested tree unless he makes up his mind to watch the tree closely and spray thoroughly once a year for some time to come, and better, twice a year for the first year or two. Does It Pay to Spray. This question has been answered partially in the previous topics. Ultimately it is a question which must be answered by each man for himself. Where the owner of a few trees has to hire somebody to 42 THE SAN JOSE SCALE. spray, pay him at a dollar per tree, and then gets perhaps 25 cents worth of fruit from each tree, he will naturally soon begin to think that spraying does not pay. When he learns how to do the work him self, however, in an efficient manner, it can be done for much less than the above figure, and no doubt most of the people who grow trees would be willing to keep them, even if the fruit barely pays for the expense of growing them. So far as the large grower of trees is concerned there need be no question. The law of supply and demand will so regulate the price of fruit that a reasonable return for the expense of raising will be received. At the present time, owing very largely to the presence of the scale all over the country, fruit is quite high in price, and there are examples in our State, as well as in others, that the men who spray thoroughly are reaping a good harvest. Aside from the destruction of the scale, other benefits which results from spraying, such as, cleaner and healthier trees, and the prevention of various plant diseases, are looked upon by many or- chardists as sufficient to pay for the expense of treatment. PRESENT MEANS OF CONTROLUNG THE SAN JOSE SCALE. The means of controlling the scale at the present time vary a little with conditions, but may be divided into: first, general orchard treatment; second, spraying; and third, fumigation. General Orchard Treatment. This includes, first of all, care in the purchasing of trees to see that the stock is not infested. As we have noted in previous discussions, the scale owes its distribution throughout the country almost en- tirely to dissemination on nursery stock. It is therefore of great importance: first, that no nursery stock should be purchased which does not bear a certificate showing that the nursery has been in- spected by authorized inspection officers; and secondly, if there is any suspicion that the scale may be present in a nursery — and such a THE SAN JOSE SCALE. 43 suspicion is warranted for more than one-half the nurseries in the East — the grower should see to it that the stock is thoroughly fumi- gated with hydrocyanic-acid gas, either by the nurseryman or by himself. The old-fashioned idea of high-headed trees must also be changed. The trees should be headed low so that all parts can be conveniently and economically reached with spray remedies. The necessity for such a plan is not an unmitigated hardship, because it has been found to be more economical to have low-headed trees, not only for all kinds of spraying, but also for pruning and the harvesting of crops. When we arrive at the time to which everything now points, when thinning of all kinds of fruit will be more generally practiced, these low-headed trees will again be found most desirable. Im- plements are now made whereby cultivation of such trees is rendered easy, and the old argument for high-heading, namely, that the branches must be far enough above the ground so that horses can be driven under them, is no longer tenable. The low-heading necessitates, for most of the standard longer- lived varieties, a somewhat greater distance between the trees. Where 35 feet has formerly been recommended as the maximum distance, 40 feet is now the rule. Pruning is also much more es- sential than it has been in the past, not only because of the greater economy of time and material in spraying when surplus wood has been removed, but also because of the need to so shape the tree that it may produce a maximum of good-sized, well-shaped, and well-colored fruit, and a minimum of second-class fruit. Hand- in-hand with this goes the need of cultivation and fertilization, which has already been mentioned. It is coming to be realized that plants, physiologically and pathologically, are subject to rules similar to those which operate in the animal kingdom. One of the most important of these rules is that a plant in a thoroughly healthy and thrifty condition will resist injury from diseases or from insect parasites in a far greater degree than one which is in a neglected condition. It is obvious, therefore, that the cultivation 44 THE SAN JOSE SCALE. and feeding of the trees so as to put them in a thoroughly healthy condition is of prime importance. Spraying. The discussion so far may be said to deal with preventive meas- ures, but in the case of the scale, even, after the greatest care has been exercised, it is likely that the grower will still have trouble on his hands, and when the pest once gets a foothold in his orchard, the only possible remedy is the application to the trees of proper insecticides. Brief General History of Spraying for the San Jose Scale. The dangerous character of the San Jos^ scale was learned very soon after its discovery, and experiments in methods of treatment were at once taken up both by the State of California and the United States Department of Agriculture. One of the first remedies tried was a lime-sulfur and salt prepa- ration which had been used hi California as a sheep dip. It was found to be quite successful and soon became a standard remedy in that State. When the scale was discovered in the East, the De- partment of Agriculture instituted experiments to try the efficiency of this same wash on the trees where the scale was found. For some reason or other, probably unfavorable climatic conditions, the remedy seemed to be a total failure and was abandoned for a time. Kerosene emulsion having been successfully used as a contact insecticide for some time, attention was next turned to this and other oil preparations with a view of securing some efficient spray remedy. The kerosene emulsion, made according to the standard formula, was soon found inefficient, impracticable and too expensive, and extensive trials were made with kerosene and water and crude oil and water mechanically mixed by means of pumps especially prepared for the purpose. The general purpose of the experimen- THE SAN JOSE SCALE. 45 tation was to determine the insecticidal value of the oil solutions, and also their effect upon the trees. It was at first supposed that an efficient remedy had been discovered in crude oil, which, when applied in sufficient strength, would generally destroy the scale. It was found, however, that the results were in many cases unsatis- factory because, of the injury to and sometimes total destruction of the trees to which the remedy was applied. Attention wa& again turned to the lime-sulfur wash, not only by the Department of Agriculture, but also by various experiment stations throughout the infested regions, and this time with a great deal better results. Later a new kerosene oil remedy, prepared by mixing a hydrated lime called "Limoid" and kerosene, ready-made lime-sulfur washes, and a number of so-called "soluble," or more correctly, miscible, oil preparations have been recommended, all of which are considered more or less successful by various experiment stations and growers. A few years ago a certain agricultural newspaper took up the discussion and announced that caustic potash was a sovereign remedy for the scale. When applied at a certain strength it was undoubt- edly efficient in destroying the insect, and the success at first was such that it promised to become a universal remedy. Although it was not generally recommended by agricultural experiment stations, its success was such that many who used it were inclined to criticise the station workers for their slowness in discovering its virtues. This conservative attitude on the part of the experi- ment stations has, however, been amply justified in recent develop- ments, for we no longer hear caustic potash recommended as a remedy against the scale. History is repeating itself at the present time in that experiment stations are being criticised for not unqualifiedly recommending the use of the miscible oils. The champions of these remedies argue that the oils are much easier to prepare and apply, are fully as effect- ive as the old-fashioned lime-sulfur wash, and but little more ex- pensive. Two or three stations in their experiments have gotten 46 THE SAN JOSE SCALE. very satisfactory results from the use of these oils and are recom- mendirig them freely. In other cases, however, the stations have not had such good results, and as the oils have not been used long enough by all kinds of growers on different kinds of trees to fully establish the effect of more or less continuous use, general recommendation has been withheld. The Lime-Sulfur Wash. The weight of opinion at the present time seems to be in favor of the home-made, boiled lime-sulfur wash, and since it is of con- siderable importance to understand the methods of preparation of this remedy, a somewhat extended discussion of it will be given. Since the lime-sulfur wash was first used, a great many formulas for its preparation have been tried and recommended. In its early history in California it was made from lime, sulfur, and salt, and when the first experiments were conducted in the East the California formula was followed, the only variation being in the proportion of the ingredients. In Oregon an attempt was made to combine in the lime-sulfur wash greater efficiency as a fungicide, and a quan- tity of copper sulfate was added. In the East the disagreeable work of preparing the wash by boiling led to an attempt to find some means by which it could be prepared without this labor, and the addition of caustic potash and carbonate of soda was recom- mended. Recent experiments have indicated that the addition of salt is unnecessary, and that the attempt to increase its fungi- cidal properties by the addition of copper sulfate is detrimental. Preparations with caustic potash and soda have been found less efficient and more expensive than the boiled wash. The following formulas will give an idea of the different ways in which the remedy has been prepared: THE SAN JOSE SCALE. 47 1 e 3 CO 1 3 1 as -0 o 02 .2 3 6 a a o o "3 E a 35 51 <0 a lll§«?s^ CD prayer in operation. Plate. 'XII. For explanation and discussion see pages 66 to 73. Fig 1 -Invincible Mounted Sprayer- Wallace Machinery Co. The spray liquid is pumped into an airtight tank together with compreLd air by pumps driven from the wheels. When machme is standing still.the compressed air continues the work. Fig. S.-Gasolene power sprayer with air cooled engine. Plate XlV. Plate XV. Niagara Gas Sprayer with Tower. Note the carbon dioxide gas- cylinder from which power to force liquid out of large tank is de- rived. See page 68. Fig. 1.— Plant for preparing lime sulfur wai-h with steam. F(G. 3. — Cooking lime-siilfur wash with steam. Plate XVI. For explanation see page 51. Plate XVII.— Hexagonal Fumigator for trees. This fumigator is made in sections and is taken, apart in moving. For explanation see page 76. CO w > » B w' (IB ?— ; P'S - § » s CO 00 tr S' ° ^ 25 B r CO ^ £, ^ 00 g * f "^""I'f^^'^m i^^ CI) O J H Z 4'x4-' 4-x6' 3^ TT VkNTlU/VTOR S'x4-' 10 xlV Ventilator ' Jl ^ "Door 4-'x65 '/ Felt, Section or Door Platk XIX. For description see pages 80 and 61. LIBRARY OF CONGRESS 000 889 003 1 1 E. L. FREEMAN COMPANV STATE PRINTERS PROVIDENCE , R. I.