UNIVERSITY OF ILLINOIS Agricultural Experiment Station. URBANA, JULY, 1899. BULLETIN No. 56. RECENT WORK ON THE SAN JOSE SCALE IN ILLINOIS. The work of this office on the San Jose scale for the years 1897 and 1898 has been in part purely practical and in part scientific. It has included a continuation of the search for infested Illinois localities and a thoroughgoing examination of those detected, as begun in 1896; the inspection of Illinois nurseries and nursery stock as a basis for official certificates issued to nurserymen; the insecticide treatment of infested premises in Illinois, undertaken to arrest the spread of the scale in this State; the collection, study, cultivation, and introduction, into orchards of two fungus parasites of this scale; field experimentation with special insecticides and insecticide apparatus; and a study of certain minor points in the life history and cecology of this insect. The search for infested Illinois localities has resulted in the dis- covery of six * points not on the list given in ‘my last biennial Report, thus making twenty-five} such localities now known in Illinois. 29,.°97) HESS: 1.50 1.50 P.S. Peterson & Son. .|/Chicago ....|Mar. 7, 8, ’98| H. E.S. 8.75 8.75 JW. Miller Cowss.c;. Freeportte ihe pee 8 Ob riaeo ae 6.50 6.50 Piminewoettavocna be Freeportec co) ci") 10,5 O82 sss, 6.50 6.50 Lebkicher'& Spitler,..|Freeport.42 0" 931,09] Eis eS. | ee ee 6.50 Hoe Cotta. aes on see cnt Nursery.) 2 12, OSH Eos, 8.95 8.95 ease Vaughan. ss Chica goy, U..)-e ee 14s Ooela tees. Fas 7.752 I, DCUYOEd ert hanes Bloomington |April 4, ’98) H. E.S. 6.66 6.66 R. Douglas’Sons...... Waukegan ..| ‘‘ 19,98] E. B. F. 18.76 18.76 Rob't C. Uecke....... Harvard 723s} -# (225; 298i) Bale 21.07 21.07 foGe Vaughan. sn 2 Chicago..... Aug. 25, '98| E. B. F. L1.03 11.93 R. Douglas’ Sons..... Chicagov;+:. i> 27, “OS -E=Bar- 13.73 13593 Spaulding Nurs. & Orch. Co..../Spaulding ../ ‘‘ 30, ’98) R.W.B. 10,92 10.92 Phoenix Nursery Co../Bloomington |Sept. 1-4, '98; R W. B ater 30°94 W.W. Thomas...... Makanda. i) 5,- 98] E. B..F: 3.04 3 04 Ass ELGOTAGLY. mc sete et Makanda: «Sabb og ee ba 3.04 3.04 Di We Leib & Son. < Makandas., ste" OGG) rs oe Ee 4.51 4.51 W. A. Watson & Co.../Normal.... LO>6 27%.1 OO, avy. i, 8.54 8 54 Kop ts. Uecke > ..0 = Harvard sci 7 ST both, Gas 2.00 2.00 Galeener & Thacker ..|Vienna..... im Gr Bes LG 10.09 10,09 Pon Gul Noenis 7 ge Bloomington; ‘' 8, Jos RIVY eB: 6.00 6.00 Augustine & Co... ..3. Normal. nS 9g, '98| R.W. B. 6.10 6,10 Arthur Bryant & Son..|Princeton...| ‘'15,16, ’98| R W. B. 16.50 16.50 Alpha Nursery Co. ../Alpha.. ; 17, 98) R.W. B. 7.59 7.59 L. 8. Frese (Forest Oak Nursery).|Coatsburg. . . | 19, 98; RW B. 12.69 12.69 GustavKlarner(Quincy Star Nurseries)..... Oumcy>, 44 21, '98| R.W. B. 13.44 13.44 PIOUATO. E iatas Gs ee Melville Sai 396-26; os. te Coats 3.29 3.29 SUELO Ce ON ee aye Upper Alton| ‘ 26, ’98| E. C.G. 3.29 3.29 Theo. Bechtel........ Staunton» jee SNe, PORT me Geta 2.00 2.00 P. S. Peterson & Son..|Chicago.....j/Oct. 4, 5, °98| E B. F. 19.66 19.66 Custer Brothers...... Normal..... RBS Ooh kee VV aks. Faere Goi 0 Missing Link AppleCo.|Clayton..... We 522 OO 15 nr 19.25 19 25 DiveeAI LS S015 oo hee Meee Dundee..... «8.20.0 QoL rosubee ks: 20.81 20.81 In nearly all cases the nursery stock examined was still standing in the rows; a fact which made it usually impossible to ascertain anything directly with regard to the condition of the roots. cable inspection of large nurseries can give at best only a rather loose approximation to a knowledge of injurious insects infesting them—at least on a small scale and to an obscure extent. Indeed, any practi- Our inspectors could only walk through the nursery plats back and forth at intervals of several rows of trees, judging of the general condition of the planta- - 1899. ] WORK ON THE SAN JOSE SCALE IN ILLINOIS. , 251 tion, stopping now and then to examine an individual tree, and giving careful attention only to trees whose general appearance indicated the possibility of insect injury. Of course no premises were found entirely free from insects commonly classed.as injurious. In the great majority of cases, however, those present were kinds which would necessarily be left behind in the shipment of clean young nursery trees, and without exception all were common widespread insects of the region or of the state at large. It is clear, however, that no certificate, however carefully it may be drawn, or however thoroughgoing may be the inspection upon which it is based, should be taken as more than presumptive evidence of the entire absence of seriously injurious insect pests. Indeed, in the hands of any except a thoroughly reliable and honest nurseryman it is entitled to no credit whatever, but may be even worse than no certifi- cate at all, since it would be perfectly easy for an unscrupulous dealer to deceive first the inspector and then his customer, and this with little or no danger of detection. The inspector, of course, must take the word of the nurseryman as to the extent of his property, and can only presume that he has seen all the stock from which the owner is likely to draw for sale, for if deceived in this regard he has usually no means of detecting the deceit. On the other hand, there is no certain means of limiting the use of the certificate to stock actually grown by the nur- seryman or on the grounds where the inspection was made. Duplicates of it may be used, with perfect security from detection, upon any stock from any source, received perhaps long after the last inspection was made. So far as the official certificate tends to give a sense of security to the customer in dealing with a nurseryman he does not know or in whom, if known, he does not have full confidence, it is undoubtedly an evilinstead of a benefit; but notwithstanding these drawbacks to its use, it will be difficult, I think, to devise any satisfactory substitute for it, as it is now commonly worded and as it should be generally understood. INSECTICIDE TREATMENT. Heretofore and in other states under circumstances such as existed in Illinois in 1897, either nothing has been done in the general behalf, the San Jose scale being left to the care of individuals acting in their own interest, or laws have been passed establishing some state authority competent to deal with the economic situation. In Illinois an attempt was made to secure such thoroughgoing legislation at the biennial ses- sion of the state legislature for 1897. A bill establishing a state board of horticulture with ample powers of inspection and police was intro- duced in both houses and passed the senate by a unanimous vote, 252 BULLETIN NO. 56. [ July, but was vigorously opposed while in the house and finally failed in committee, the only immediate result of the effort being an item in the general appropriation for the expenses of the state government appro- priating $3,000 to the State Entomologist ‘‘ for experiment, publication, and instruction concerning the San Jose scale, and for the inspection and disinfection of orchards and nurseries.” It thus became a part of the duty of the Entomologist to do every- thing possible to exterminate the San Jose scale in Illinois wherever it had been or might be detected or, if destruction should prove impracti- cable, at least to check its multiplication and spread as vigorously as possible, and to give to owners of infested premises full instruction with respect to precautionary and remedial measures. It was also clearly intended that the office should act to protect the state as far as practi- cable against the dispersal of the scale through the nursery trade. With a view to the discharge of these duties the following circular was issued in July, 1897: : An appropriation of $3,000 was made to the State Entomologist of Illinois by the General Assembly at its last session, ‘‘ for experiment, publication, and instruction concerning the San José scale, and for the inspection and disinfection of orchards and nurseries.” It is the earnest desire of the Entomologist that this sum may be used to the best advantage to disclose the present condition of the fruit interest of the state with reference to this pernicious insect; .to exterminate the scale promptly wherever in Illinois it has been or may be found; to protect the nurseryman and fruit grower as far as practicable against the chance of future invasion; and to assure the customers of Illinois nurserymen and of other dealers in fruit plants that Illinois stock offered for sale is free from this pest. It was the evident intention of the legislature to trust the control of this important matter to the public spirit and enlightened business enterprise of the private citizen, aided in every practicable way by the official Entomologist. It is the purpose of this circular to make to allinterested a cordial offer of information, advice, aid, and super- vision of insecticide operations, as far as the resources at our disposal will permit; and also to ask early and full information from all concerned with reference to the occur- rence or introduction, known or suspected, of the San José scale in Illinois. LOCATION OF COLONIES. It must be our first endeavor to discover promptly and to locate exactly all the colonies of this insect now established in the state. Eighteen such colonies have already been found, nearly all by an inspection of premises to which we have had reason to believe that nursery stock was imported at a time when the nurseries from which it came were infested by this scale. It is of great importance that we have at once full information concerning all importations into the state from places and at times such as to make it possible that the San José scale was conveyed by their means. I consequently earnestly request all to whom this notice may come that they will send to this office prompt and precise information with regard to the importation into Illinois of nursery stock or other trees or plants subject to its attack, which were grown in any of the following localities within the time mentioned after each: Cali- fornia, since 1873; eastern New Jersey, between 1886 and 1894; Maryland since 1887; 1899. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. 253 Florida, since 1889; Washington State and Ohio, since 1890; Georgia and Louisiana, since 1891; Long Island, N. Y., since 1892; Delaware and eastern Massachusetts, since 1893. The plants thus far found subject to injury by the San José scale are the apple, pear, peach, apricot, plum, cherry, quince, grape, raspberry, blackberry, gooseberry, currant, and persimmon, among our fruits; the chestnut, hickory, pecan, English walnut, black walnut and almond among the nut-bearing trees; the oak, basswood, elm, catalpa, birch, poplar, and willow among our shade and forest trees; and a large miscellaneous list of trees and shrubs, including the rose, thorn-apple or red haw, crab-apple, wahoo, spirza, loquat, cotoneaster, flowering quince, flowering currant, acacia, alder, and sumach. This insect also seriously infests the osage orange, spreading with the greatest facility through the thick growth of the wayside hedge. It is very important that all supposed or possible cases of the appearance of the San José scale in Illinois be reported at once to this office, accompanied by twigs or pieces of bark illustrating the supposed attack. To all communications accompanied by such specimens prompt reply will be made, and energetic measures for its destruction will be taken wherever the scale is thus detected. EXTERMINATON OF THE SCALE. To owners of premises on which this scale is found the Entomologist will give all information and assistance necessary to the prompt extermination of the pest, sending an agent to inspect: the situation and surroundings, to give personal instruction as to methods of procedure, and to supervise and direct insecticide operations, An effi- cient spraying apparatus will also be furnished for use where this cannot otherwise be readily obtained. This proposition is made on the sole condition that the owner will destroy stock hopelessly diseased and will provide the necessary insecticide and the labor for its preparation and for its distribution to infested stock, and that the whole operation will be carried on and continued to the satisfaction of a representative of this office. Experience elsewhere has shown that expert assistance of this sort is, as a rule, necessary to insure success; and expenditure of public money in such an interest can be justified only on condition that everything is done needful to the accomplishment of the end desired. A The San José scale is commonly regarded by those best informed concerning it as the most dangerous and injurious insect enemy of American fruits. It now occurs in Illinois in comparatively small colonies, where in most cases it can probably be exterminated at small expense. Considering the enormous loss which is likely to fall upon the horticulture of the state if this highly destructive insect is allowed to spread generally throughout our orchards and to infest our nurseries, it is to be hoped that every person upon whose property it appears will regard the situation in the light of the public welfare as well asin that of his private interest, and that he will take without hesitation such measures as may be necessary to protect both. BULLETIN OF INFORMATION. An illustrated bulletin of information concerning the San José scale and its dis- tribution in Illinois has been published by the State Agricultural Experiment Station {Bulletin No. 48), and will be furnished on application to Prof. Eugene Davenport, Director of the Station. A later and more comprehensive article upon the subject will appear in the forthcoming biennial report of the State Entomologist, which will probably be ready for distribution this fall. * * For omitted section see page 248. 254 BULLETIN NO. 56. [ July, In accordance with the propositions of this circular, preparations were made during the summer of 1897 for a thorough and general in- secticide treatment of all infested premises, to begin as soon as the leaves had fallen from the trees, this postponement being essential to any reasonable assurance that all the scales on an infested tree would actually be reached. DESCRIPTION OF APPARATUS. The principal apparatus used is a large and complicated machine sprayer consisting of a one-horse power gasoline engine, a three-cylinder force pump, and a large double galvanized-iron tank with a powerful gasoline heater beneath for making the solution of whale-oil soap. Besides this apparatus, intended for use in large orchards or in com- munities where a considerable number of infested places were separated by short distances, we had in use from one to three hand-sprayers of the kind ordinarily used in orchard work. The machine sprayer (Plate II.) is mounted on a two-horse baggage wagon, under the seat of which are placed the battery and the gasoline tank to supply the burners. Immediately back of these, on the first third of the floor space, is the engine. The large heating tank comes next. It is set close to the right side that there may be room on the left for the belt which connects the engine with the pump. The pump occupies the remaining room in the back. The wagon thus loaded weighs 2,400 lbs. The gasoline engine (Plate III., Fig. 1) which drives the pump was manufactured in the University Shops. It has a four-inch cylinder witha four-inch piston stroke. The gasoline vapor is made by the flow of air over a gasoline jet from a needle valve on the right side, this jet being caused by gravitation from a supply tank placed higher than the engine and above the wagon seat. Gas is drawn into the cylinder from the vapor chamber to fill the partial vacuum caused by the previous explosion, a valve to allow this being opened each time the piston passes the center. The vapor when under a back pressure of forty pounds is exploded by an electric spark caused by an inter-cylinder contrivance making and breaking the current from a sixteen-cell battery. The pulley wheel is nine inches in diameter and makes about four hundred revolutions per minute. The engine is rated at one-horse power. Just back of the engine is the tank, firmly attached to a three- eighths by one and a fourth-inch iron frame raised sixteen inches from the floor of the wagon. - There are six legs of the same material as the frame, each bolted to the floor. Beside these legs two braces extend forward from the upper part and are bolted to the flour, one on either 1899. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. oD gies side of the base of the engine. The tank is of heavy galvanized iron, fifty-six inches long by twenty-six inches wide, and twenty-seven inches deep. Its capacity is one hundred and seventy gallons. A partition runs crosswise through the middle, and each section thus made has a twelve-inch opening in the top and a cap for the same. In the left-hand corner, toward the rear, each section empties through an inch pipe into the system leading to the pump. A valve on this pipe admits the shut- ting off of the section from the feeding system at will. Another valve allows the direct emptying of the section without passing its material through the pump. Each section of the tank is provided with like valve and arrangements, and contains a strainer so placed that all liquid pass- ing to the outlet must run through it. Beneath the tank are two sets of gasoline burners (Plate III., Fig. 2), each set having twelve burners, all constructed on the same principle as is the common plumber’s torch. Gasoline comes to them through a pipe on the right side of the wagon from a tank under the seat. To this tank is attached an air pump and a pressure gauge. While in use a ten-pound pressure is maintained. By means of valves, one or both sets of burners may be in use at one time, and the construction is such that each burner may be shut off or caused to burn low. The floor of the wagon under the tank is thickly covered with asbestos and cement, which protects the wood and forms a foundation for the pipes which support the sets of burners. Within the iron frame are two side- and two end-strips of gal- vanized iron which protect the burner flames from wind and help retain the heat beneath the tank. The pump is of the triplex type, having three one and three-quarter -inch-cylinders capable of a two and a half-inch-piston stroke. The pumping capacity is 0.07 gallon per revolution of crank shaft, or from 2.8 gallons to 4.2 gallons per minute when run within recommended speeds, and the pump will operate against one hundred and fifty pounds per square inch. A one-inch feed-pipe enters from the tank, which is elevated, in the manner stated, above the body of the pump. The dis- charge may be through a one-inch pipe or through the series of four quarter-inch cocks arranged on a cross-pipe which is connected with the one-inch discharge. The belt runs on a twelve-inch pulley with a two and a half-inch face. There are two pulleys, one loose on the shaft. A three-eighths inch pipe is connected up with the discharge and the water jacket of the engine cylinder, and this cylinder again with the “feed-pipe, thus allowing a flow through the water jacket. ‘The rate of this flow is governed ‘by a shut-off valve on the jacket feed-pipe near the cylinder. When only two quarter-inch hose are in use this valve 256 BULLETIN NO. 56. [ July, may be opened sufficiently to cause not only the circulation in the water jacket, but also to relieve the increased pressure on the two hose. Beside the main parts of the outfit, as above mentioned, there are two tool boxes, about one hundred and fifty feet of three-ply quarter- inch rubber hose, poles and extension rods for spraying higher parts of the trees, pails for carrying water, and gasoline cans. The larger tool box is 8.5 in. x 41 in. x 32 in. outside measure, and was made in this form that it might occupy the space between the tank and wagon box, on the left, when moving from place to place. In this box are the work clothes, a spade, hatchet, nozzles, reducers, wrenches, wire-cutters, packing, screw-driver, and other articles used in connection with the spraying operation. The smaller box is 12 in. xX Ig in. x 20 in., and was made to occupy the space between the engine and the tank. It contains the oils and smaller renewal parts for the engine. A large tarpaulin covers the whole apparatus, and by means of short ropes attached to its edges may be securely fastened to the wagon- box, so that in shipping, engine, tank, and machinery are all under shelter and protected from the weather. DETAILS OF TREATMENT, WITH RESULTs. At Dundee, Kane county, all the trees (apple, peach, and mountain- ash) upon which the San Jose scale could be discovered were dug out and destroyed in the presence of my Assistant, Mr. R. W. Braucher, November 20, 1897. Everything in the block of trees in which this in- fested stock was found was, in fact, so destroyed at this time except some shade trees—black walnut, horse chestnut, white elm, hard maple, birch, and basswood, and these were thoroughly sprayed with whale-oil soap. A few white-ash seedlings in this block were not sprayed. The apple-, cherry-, and pear-trees in the vicinity, and scattered soft maples, rose-bushes, and syringas next the infested block were sprayed, leaving without treatment only the ornamental shrubbery farthest from the trees infested. These premises were very carefully inspected again September 7, 1898, by Mr. E. C. Green, of my office, and still more fully, October 28 and 29, 1898, by Mr. E. B. Forbes, the first inspection to ascertain, for my own information, the effect of the insecticide procedure there, and the second, made at the request of the owner, to serve as a basis for a certificate of freedom from the San Jose scale and other injurious insects and fungous diseases. Both these skilled and careful observers reported after this interval of nearly a year from the time of treatment that there was no trace of the San Jose scale to be found on these 1899. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. Log OST grounds; but to make assurance doubly sure I required the destruction of all stock on the infested premises which could possibly harbor and maintain the scale, designating the various lots and kinds of trees and shrubbery objected to. This requirement had been made good by January 16th, and an unqualified certificate of apparent freedom from the San Jose scale and from all other dangerous insects and from fungous diseases capable of being transported with nursery stock to the injury of cus- tomers was issued under that date. At Monroe Center, in Ogle county, the single pear-tree originally first infested had been cut off close to the ground and burned by the owner, and the bark had been removed from the stump for some dis- tance below the surface. Two shoots three or four feet high which afterward grew up from this stump in the summer of 1897, showed no signs of the scale November 18th of that year. Traces of the scale were found, however,-on two eight-year old Rocky Mountain cherry-trees and on some sprouts of another pear-tree near by. All the infested bushes and trees on this lot and everything near by were thoroughly sprayed at this time with whale-oil soap—one hundred and fifty trees - and shrubs in all, including peach, pear, cherry, apple, and plum, grape, goosebery, currant, Rocky Mountain cherry, etc., and not a scale could be found on these or on any of the surrounding vegetation by Mr. Green, who visited this place September g, 1898, for the purpose of ascertain- ing the effect-of the treatment. On Mr. Jacob Winzeler’s place, two and a half miles south of Tre- mont, everything on the premises lable to attack by the scale was sprayed with whale-oil soap by Mr. Green March 28, 1898. Nine hun- dred and forty fruit-trees and shrubs were thus treated, and also fifteen large maple-trees about forty feet high. Ona visit of inspection made nearly six months later (September 14th) Mr. Braucher reported that he found a few living young San Jose scales, about half grown, on three large peach-trees, but that otherwise the premises seemed free from the - scale. The large maple-trees had been badly damaged by the spray, many of the lower branches having been-killed, evidently by the drip from the branches above. * On Mr. P. B. Stem’s place, three and a half miles north of Manito, two hundred peach-trees and twenty-five apple- and quince-trees were cut out, and also twenty rods of osage-orange hedge. Nine hundred trees were treated in this orchard, ranging in age from six to ten years. As none of these had ever been trimmed, about three days’ work of four men was required to prepare them for treatment. The spraying upon the 7th and 8th of April, 1898,. was followed by a heavy shower in the _ * All infested trees since destroyed. 258 BULLETIN NO. 56. [ July, night, and the whole orchard was consequently sprayed again, the work being finished April 11th. Five months later, September 14~16, 1898, a critical inspection of this whole orchard was made by Mr. Green. On one peach-tree six living scales were found on new wood; on eight other peach-trees one or two scales each were found; and on each of six others from one to seventeen scales remained—mostly on new wood but some under bits of bark on the older growth. Ona single peach-tree a - colony of one or two hundred scales was found upon a branch, a part of which had evidently escaped the spray. Except for this single colony the total number of scales found on a very careful search of everything in and near this orchard which had been previously infested resulted in the discovery of about fifty living scales. According to the report of Mr. Braucher, as summarized in my last entomological Report (page 15), about ninety-nine per cent. of the San Jose scale in the orchard of Mr. Kiem, near Quincy, had been killed by two successive sprayings with whale-oil soap, made in the fall of 1896 and the spring of 1897. That this was not an overestimate of the efficiency of the treatment is shown by the report of Mr. Green, who visited this orchard April 13, 1898, and upon a rigid examination could find no living scales on the premises except on the trunk of one small apple-tree. He proceeded, according to his instructions, to treat thoroughly a third time all the trees (twenty in number) which had originally been badly infested, first scraping the trunks and removing the earth from about the bases. Hot soap solution was brushed on with stiff brooms up to the uppermost twigs, and these were sprayed except in a few cases where they were perfectly fresh and bright, evidently never having had any scale upon them. A very critical examination of this orchard made September 20, 1898, by the acute and careful in- spector, Mr. R. W. Braucher, showed that the San Jose scale in this orchard was, however, far from being exterminated, living scales being detected on several apple- and peach-trees which had been badly infested when the treatment of this orchard began. One apple-tree had been so badly incrusted with the scale that especial pains was taken to treat it thoroughly. The limbs were cut back to a few short stubs, the bark was scraped, and the tree was thoroughly coated with strong soap solu- tion by means of a brush. Pieces of bark clipped from this tree showed, nevertheless, that it was still slightly infested by the scale. At Paloma, visited April 17th, where one infested tree had been previously found, no scale could be detected. This tree had been taken out and burned, and others near it had been twice sprayed by the owner with whale-oil soap. Mr. Lowe’s orchard of five acres at Auburn, in Sangamon county, 1899. |. WORK ON THE SAN JOSE SCALE IN ILLINOIS. 259 was found by Professor Summers very generally infested, together with a hedge adjoining. This whole orchard and two rows of another orchard adjacent to it, not infested, were thoroughly sprayed by Pro- fessor Summers the first week in January, (898. The infested hedge was not treated, as the owner promised to destroy it. September 17, 1898, it was found by Mr. Green that this orchard was by no means free from the scale, a considerable number of trees—apple, pear, peach, and plum—still showing from one to a dozen, twenty, or more, living scales. A few scales were also found upon apricot trees in an old orchard near by which was not: treated by Professor Summers. The situation at this place was on the whole quite unsatisfactory, and the premises will. doubtless become thoroughly infested again within the course of two or three years unless additional measures are taken for _ the destruction of the scale. The infested hedge mentioned above had been twice cut down, but had not been killed. : The infested trees on Mr. Henry Archer’s place, two miles from New City, in Sangamon county, were scattered through the western end of an orchard of about five acres. These were mostly young, but a few of them were large peach-trees, and others were of various sizes inter- mediate. All the very badly infested trees were, however, very small, and the scale had apparently spread but a short distance from them. About sixty trees were sprayed in this orchard in January, 1898, includ- ing, of course, all those visibly infested but going some distance beyond them. September 18, 1898, about seventy trees were found still infested with the scale, commonly not more than from ten to twenty specimens onatree. It was also found in an old orchard adjoining the one prin- cipally infested and which had not been sprayed by Professor Summers in January. At Assumption, in Christian county, the entire small orchard be- longing to Mr. Tobias on a city lot on which a single infested tree had been found, was sprayed February 12, 1898, by Mr. Green, and the pear-tree on which the scale had been brought to these premises was dug out and burned. This tree was one of six obtained by mail from a Philadelphia dealer. The remaining five were found in the hands of other citizens, all free from the scale except one belonging to Mr. Hiram Hooten,: which bore a few specimens sufficiently like the San Jose scale to give ground for suspicion. This tree was thoroughly sprayed by Mr. Green. September 20, 1898, on a single tree (a quince) Mr. Green found one San Jose scale; otherwise the trees on Mr. Tobias’s lot seemed free from the scale. | At Tower Hill early in February, 1898, two trees on Mr. Grisso’s place were cut out and burned, six were thoroughly sprayed with soap 260 BULLETIN NO. 56. [ July, solution, and others adjacent were partly sprayed. On Mrs. Connor’s - place one tree was dug out and seventeen trees were sprayed. Septem- ber 21, 1898, Grisso’s place was found in rather bad condition. On three of the trees sprayed in February from three to eight living scales were detected by Mr. Green; on two adjacent trees not sprayed the San Jose scale was found, the trunk of one being covered and its upper branches infested; and on another part of the place, a hundred rods from the infested trees above mentioned, three trees were found badly incrusted with the scale, one an apple, one a plum, and one a flowering quince, <-1t3i8 probable that the scale-is generally distributed on Mr. Grisso’s place, and that only a thorough insecticide treatment of the whole of it can check its spread effectively. On the village lot of Mrs. Connor no scale was found at this time. At Herrick, in Shelby county, it.was found that the owner had removed the infested trees in August, 1898, and burned them up. A very careful examination of eight others, planted near them and sepa- rate from the main orchard of the owner, was made by Professor Sum- mers February 12, 1898, but no trace of San Jose scale could be found upon them. Spraying at Ernst, January 18 to 24, 1898, was attended by unusual difficulties and much delay owing to unfavorable weather, frequent rains probably washing off much of the soap. Work began January 18th and continued through the forenoon of the rgth, but was then interrupted by rain which lasted all the afternoon and into the night. The 2oth was too windy for orchard work, but spraying began again on the 21st and was followed by rain—in part violent showers—nearly all the 22d. On the afternoon of the 24th spraying began again, but was followed at night and in the morning by several hard showers. One hundred and sixty- four trees were sprayed in all, ranging from yearlings to trees fifteen feet high; and, besides these, rose-bushes, currants, gooseberries, honey- suckles, etc. ; Notwithstanding this unusual exposure to rains, Mr. Green could find March 24th only nine living scales on these premises, six under a bit of bark upon a pear-tree and three on a currant bush. A great part of the premises was, however, sprayed again, seventy-two bushes and trees being included inthe treatment. Only about four hours’ work was needed, but it took six days to do it on account of daily rains. October 12, 1898, Mr. R..W. Braucher carefully inspected everything on these premises and could not find living San Jose scale upon any shrub or tree. He also observed that the whale-oil soap had generally destroyed the Forbes scale (4Aspidiotus forbest), but that the scurfy scale (Chionaspis furfurus) was but little affected by the winter application of 1899. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. 261 whale-oil soap. From seventy-five to ninety-five per cent. of the fruit buds on the peach-trees had been killed by the January treatment, but buds on the other trees were apparently uninjured. Spray applied dur- ing the latter part of March had, however, killed many buds on plum- and pear-trees. At the farm of Mr. E. L. Howard, in Edgar. county, a short dis- tance from Sandford, Ind., it was found in January, 1898, that all the infested currant bushes had been dug out and destroyed by the owner, and that the woodland brush next the infested field had been partly cleared off and burned. It was the owner’s intention, in fact, to com- plete this work the following spring as a safeguard against the possible perpetuation of the scale in this situation. A plat of quince bushes and some rows of apple-trees in the vicinity of the infested grounds were sprayed by Mr. Braucher at this time, although no San Jose scale was detected on any of these trees or shrubs. Another inspection made by - Mr. Braucher October 11, 1898, gave a similar negative result, and it seems likely that the San Jose scale has been exterminated at this point. At Mr. A. H. Evinger’s place near Vermilion, Edgar county, to which the scale had been transferred by purchase of currant bushes from the premises of Mr. Howard, just mentioned, the San Jose scale was found on only three currant bushes among some four hundred in the plantation, and on these it was so scarce as to make it little likely that it had spread to adjacent plants. All the currant bushes in this plantation, together with eighteen small plum-trees near by, were thoroughly sprayed January 4, 1898, and October 1ith no San Jose scale was to be found on this place. The colony on the place of Mr. Charles Eckert, three miles from Collinsville, was visited by Mr. Green February 18, 1898, with a view to its destruction. It had by this time made considerable progress, as is shown by a comparison of the observer’s notes with the statement published on page 1o of my last Report. Trees then slightly infested were found by Mr. Green in the last stages of disease from scale attack; and where one badly infested pear-tree was reported previously sixty pear- trees were now badly infested and some of them dead. Work here was retarded by rain and by the reluctance of the owner to allow his trees to be sprayed. Five trees were finally dug out and burned, however, and forty-eight sprayed. The spraying was, unfortunately, followed within twelve hours by about eight hours’ rain. Twenty-two trees were found still slightly infested on these premises September 27, 1898, when revisited by Mr. Green, the number of scales detected varying from one to twenty on each tree. At Mascoutah the infested premises described as_ belonging 262 BULLETIN NO. 56. [ July, originally to John Baisch* were found in the possession of Charles Clements. The small orchard contained about one hundred trees of various sizes, and the place was in greatly neglected condition, black- berries, raspberries, and gooseberries having grown unchecked, to form a dense and almost impenetrable thicket under the orchard trees. . There were no fruit trees adjacent to this lot except in one direction, across the ~ street, and no scale could be found anywhere in the vicinity. It was abundant, however, on a row of peach-trees about the middle of the lot, and had spread from these to blackberries beneath. The owner declined to allow any trimming of trees or any removal of shrubbery, but Pro- fessor Summers made, December 8, 1897, a persistent effort to spray thoroughly everything on this lot, using nearly six hundred pounds of soap. The scale was nevertheless found by Mr. Green September 28, 1898, on about thirty of these trees, the number detected ranging from ~ one to twelve per tree, except in a single instance, apparently over- looked earlier, of a peach-tree thickly infested throughout. _ At West Salem, visited by Mr. Braucher February 4, 1898, all the trees known to.be infested on Mr. Fishel’s premises were sprayed, to- gether with adjacent trees for six rows in one direction and four in another. Sixty-one trees were treated in-all, ranging from six to eigh- teen feet in height. From Mr. Braucher’s report of a visit made October 28, 1898, it appears, however, that this spraying was not carried far enough, as he found at the time a few infested trees outside the area sprayed, as well as eighteen within the area which still carried a very few living scales each. | The infested orchard on the farm of Mr. C. S. Frame, three and a half miles east of Alhambra, in Madison county, was treated February 25, 1898, twenty-one trees being cut down and destroyed and thirteen others sprayed after heroic cutting back.. The weather continued steady for several weeks after spraying, and the soap could still be seen upon the trees a month after it was applied. Visited September 23d and 24th by Mr. Green, it was plain not only that the treatment was but partially effective but also that the scale attack had extended farther than was supposed at the time the spray was applied. From one to a dozen scales were found on each of twenty-five trees, apple, peach, pear, and plum, still standing in various parts of this orchard. The trees had -made an excellent growth, and the living scales remaining were usually - found on the trunk beneath a thick crust of the dead or in deep cracks where young shoots started out from the old wood. At Walnut Prairie both Mr. Cline’s and Mr. Kreager’s orchards were sprayed by Mr. Green March 15 to 18, 1898, fifty-six trees and * See Twentieth Rep. State Ent. Ill., p. to. 1899. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. | 263 fifty-five bushes on Mr. Cline’s place and sixteen large trees on Mr. Kreager’s. Operations here were much hindered by rains, and part of the spraying was repeated on this account. These premises were inspected by Mr. Braucher, October 13, 1898. Mr. Cline’s orchard still gave evidence of having been very badly attacked by the scale, and living scales were found upon it in sufficient number to reproduce the difficulty within two or three years. On Mr. Kreager’s place, originally infested from Mr. Cline’s, much the same condition of things was found. The transplanted plum-tree by which the scale was brought to these premises had been very severely cut back and very:thoroughly -treated with whale-oil soap, which was rubbed in by hand and applied so freely that it formed a pool around the base of the trunk. Neverthe- less, many living scales were found on this tree by Mr. Braucher in October, especially on the young growth of the year. Several other trees on these premises were likewise still infested with living scales, which were found also on two peach-trees not sprayed by Mr. Green. The imperfect result of the insecticide treatment of these orchards is doubtless to be attributed mainly to the accompanying rains. At Mt. Carmel, five trees were dug out and two hundred and sixty- ~ two were sprayed, belonging to eleven different owners living on five adjacent blocks. About eighty feet of infested osage-orange hedge was also cut out and destroyed. Most of the trees were large and full of branches, necessitating much pruning as a preparation for the spray. One owner refused my agent admission to his premises, although an inspection on a previous visit had determined the presence of the scale on his trees. : Subsequent inspection showed that the scale was much more widely distributed at Mt. Carmel than was supposed at the time this spraying wasdone It was found, indeed, by Mr. Braucher, late in October, on no less than fifteen blocks, many of which had, of course, not been sprayed, and even on those which had been treated with the whale-oil soap it had not been completely eradicated from a single one. The failure of the insecticide to exterminate the scale is well illustrated by the fact that _ twenty-five trees and bushes were found infested in October upon a lot (Mrs. Deischer’s) where forty-eight had been sprayed the preceding March, and that twenty-three were still infested in an adjoining lot (belonging to Mr. R. K. Stees) where thirty-two had been sprayed by Mr. Green. : The situation at Richview proved on continued inspection to be much more serious than was at first anticipated, the scale being so wide- spread as to make it impracticable for us within the time remaining last spring and with the funds at my disposal, to complete the procedure 264 BULLETIN NO. 56. [ July, for its extermination at this point. Instructions were consequently given to my field assistants, Mr. Braucher and Professor Summers, to spray thoroughly those orchards or parts of orchards in which it was present in destructive numbers, and to treat also all other infested vegetation whence it was likely to spread within a year to new territory, thus arresting the ravages of the insect where it was doing real injury, and preventing the extension of the area infested by it. These measures were taken with the expectation of returning to this locality after the - fall of the leaves in 1898 fora final treatment of these premises. All of the infested property on the ground of Mr. J. W. Stanton, where the scale was first discovered at Richview, was thoroughly sprayed with whale-oil soap in February, 1898,—some sixteen hundred trees in all,—except certain badly infested trees which were dug out and burned. In addi- tion to this the premises of Mr. Jasper Wilgus, separated from those of Mr. Stanton by a country road and a high hedge fence, were very gen- erally treated, several badly infested trees being destroyed and many © others sprayed. About an eighth of a mile of hedge was cut down and burned, and the stumps remaining were profusely sprayed with kero- sene. From the orchard of Mr. Chas. Cooper, all trees originally found infested had been cut out and destroyed, but a few remained infested February 14, 18908. One of the places worst infested, a mile south of Richview, on the estate of Mr. Newcome, contained about twenty-three hundred trees. The condition of the spring weather and the exhaustion of funds avail- able for the purpose prevented the thorough treatment of these premises, but the trees originally infested were all cut out and extensive spraying was done with the object of exterminating the scale from the orchard worst infested and of reducing its numbers in other parts of these grounds sufficiently to render its spread unlikely. Approximately five hundred trees were sprayed in all upon these premises, leaving only a few partially infested trees scattered here and there. Later all or nearly all of these were infected with a fungus parasite of the San Jose scale, as will be described in another section of this article. Half a mile north of the Newcome place a single apple-tree, in a garden belonging to Mr. B. F. Johnson, badly infested with the San Jose scale, was sprayed, together with two other trees adjacent to it. A single infested tree which had been detected in an orchard immediately west of Richview, rented by Mr. Hamilton, was dug out and destroyed by the owner. Although no scale could be found on any other orchard tree, eighteen or twenty trees immediately surrounding were thoroughly sprayed by Professor Summers, and a large osage-orange hedge beside this orchard was cut out. 1899. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. 265 A prolonged inspection of one of Mr. Stanton’s orchards at this place, made by Mr. Braucher early in November, showed substantially the same results as in those previously described. The great mass of the scales had been killed, but everywhere enough remained to give origin to a new attack, which in a short period of years would equal in destructiveness the one suppressed by our insecticide operations. Fif- teen hundred and forty-four trees were sprayed in this orchard of dwarf pears, and of these, fourteen hundred and nine were examined by Mr. Braucher the first of November. Not less than one hundred and seven of these trees still showed the living San Jose scale—in a great majority of the cases in small numbers only, but quite numerous on here and there a tree. . ° As a general result of the operations above described it appears that the San Jose scale has been exterminated in seven™ out of twenty- one places treated, namely, at Dundee, Monroe Center, Sandford, Ver- milion, Ernst, Herrick, and Paloma, but that more or less conspicuous traces of its presence are to be found in all the fourteen others.+ On several of these fourteen premises it was wholly killed on many badly infested trees, but in none of them onall. Even at Quincy, where a single small orchard was sprayed, at intervals, three times in a very thoroughgoing manner, enough of the scales survived to reproduce the original condition in three or four years at most. The places where the scale was completely destroyed were those where it had made least headway and where everything seen to be infested was promptly cut up and burned, this destruction being reinforced in most of the cases by a general spraying of everything’in the immediate neighborhood on which the scale could live. There seems, on the whole, little likelihood that the spraying method can be depended on even where most thoroughly and persistently applied, to exterminate the scale on any place where it has had a few years to establish itself. On such a place the only sure remedy is the ax and the faggot, applied to every tree and shrub on which the scale is seen to have made a lodgment, supplemented by lib- eral spraying of all vegetation which may have become obscurely in- _fested. It is true that fumigation with hydrocyanic acid gas has occa- sionally been recommended as efficient for the extermination of the scale even where the trees are completely and heavily infested, and some experiments lately published, especially in a Report on the San Jose *Now nine. +Inspections made since the preparation of this manuscript show that the San Jose scale has apparently been exterminated at Villa Ridge alsoand on Mr. Winzeler’s place near Tremont. At both places, every tree upon which there was any definite reason to suppose that the scale was finally present, was cut out and destroyed. 266 BULLETIN NO. 56. [ July, scale in Maryland,* seem to sustain this recommendation. The general judgment of economic entomologists will, however, doubtless support the following statement quoted from a letter by Dr. L. O. Howard, writ- _ ten December 14, 1808. ‘‘ While hydrocyanic acid gas furnishes the most effective means of destroying the San Jose scale and many other scale insects, it is not, as some seem to suppose, an absolutely perfect remedy, and experience for many years has fully demonstrated, and also experience in the East, that here and there an occasional scale will escape this treatment, and, in the course of two or three years, it will be necessary to go over the plants again. In California, treatments are found to be necessary about every three years. Where the work is done with exceptional care, per- haps a longer period of immunity is sometimes gained.” In brief, the San Jose scale can clearly be kept in check by thor- ough spraying with whale-oil soap or by general fumigation with hydro- cyanic gas once in two to four years, according to the situation and the — rapidity of its multiplication; but it can be exterminated where it has once effected a lodgment only by drastic measures of destruction sup- plemented by careful spraying or fumigation, or by repeated treatment applied in every case just as soon and just as frequently as a watchful inspection gives any evidence of the presence of the scale. DIFFICULTIES OF COOPERATION. The state legislature, as has already been said, rejected in 1897 a plan of legal and authoritative control and substituted therefor a mere appro- priation to the State Entomologist, who ‘was thus provided with funds for an investigation and destruction of the San Jose scale, but was left without authority to compel action on the part of reluctant owners, or to proceed to act in opposition to their wishes. The success of the work of destruction was consequently dependent upon volunteer co- operation between the Entomologist’s office and the citizens most im- mediately concerned. There was commonly no difficulty in securing such. codperation, at least in the form of permission to enter upon premises and the contribution of a considerable amount of labor in the application of insecticides. It was much more difficult, however, to induce the responsible owner to share in any way the expense of opera- tion, some refusing absolutely, declining to acknowledge any responsi- bility to the community; others declining to bear any share of the expense until satisfied that the insecticide operation was fully successful; and still others agreeing, but neglecting, either to purchase the insecti- cides or to pay for them when furnished, as proposed in my office circu- *Bull. No. 57, Md. Agr. Exper. Station, Aug., 1898. 1899.|.. . WORK ON THE SAN JOSE SCALE IN ILLINOIS. 267 lar. Indeed, three owners out of the thirty or more concerned posi- tively objected to have their premises entered on. Two of these were finally prevailed upon by the use of tact and persistence, but the third successfully resisted the persuasions of the agent of my office, and his premises were necessarily left without treatment. As illustrations of the difficulties encountered, the following items from the reports of Pro- fessor Summers and Mr. Green will be of interest: ‘« Stepping into the yard of Mr. ————_,” writes Mr. Green, ‘‘I met an angry old gentleman who vehemently ordered me to move on, saying that his trees did not need any inspection. I tried to tell him about the scale, and referred him to his neighbors who were having their trees examined, assuring him that there was no charge for the inspection or the work. He would listen to nothing, however, but said that he was old enough to care for his own trees and didn’t ask the state to look after him. The last legislature, he said, was a band of thieves and rob- bers, and had started a scale scare to furnish fat salaries for two of its favorites; then further remarked that a man-had been there some time before who had gone across his lot without permission, and that now he would be glad to see the last of me. I finally apologized for troubling him and left.” At walked out to the place of Mr. —, three miles from town. The oldest son, a man of about twenty-five, showed me the _ infested trees, the mother also coming along. Some Japanese plums in ‘one corner of a large peach and apple orchard were in the last stages of disease, completely infested by the scale. In another lot were several pear-trees, all badly infested and some dead. Both mother and son tried to convince me that the trees did not need treatment, or at any rate that they could wash off the scales themselves with their own soft soap. I pointed out the trees which I was sure that it would be abso- lutely necessary for me to treat with whale-oil soap, but they said noth- ing. I asked if one of their sons could take me back to town that after- noon and bring cut the apparatus if it had come. They said the boys were busy and had no time to spare; but as a friend was to be taken to the train that afternoon, one of the girls hitched up a horse and I was allowed to ride with them. I found my spraying apparatus at the depot and sent back a note by the girl asking that the team be sent for it in the morning. Starting out to the place on foot, I met the team with a girl _ driving. She said she was going for a load of brick, and would not bring out my material without orders from home. I presently found a neighbor of the family who agreed to bring my apparatus out that day as he returned from hauling a load of wheat to town, and I sent word to Mr. — that I would be out to spray his trees, asking him to have 268 BULLETIN NO. 56. [ July, water hot that we might go to work without delay on my return. He looked more surprised than pleased when I came back with the appa- ratus, and there was no hot water. It threatened rain, and was then too late to begin, so I contented myself with their promise to have hot water ready in the morning. ‘The next day, while the boys were heat- ing the water, I pruned the trees. The boys finally helped in spraying and took the machine back to town, but the owner flatly refused to pay for the soap. The elder son, who took the apparatus to the station, became quite friendly before we separated, and told me that when I came back the second time they talked of getting the shot-gun and driving me off the place.” At another town, where the trees and bushes on a village lot were thoroughly infested by the scale, Professor Summers was met at first by a refusal to give him admission to the grounds. He ignored the refusal, however, and continued his preparations, entering upon a good ‘natured conversation with the owner. Seeing a large soap kettle at hand, he asked the use of it for boiling up his whale-oil soap. This was refused on the ground that the kettle belonged to the owner’s father and that it ‘‘might be called for any minute.” By inquiry in the neighborhood another kettle was found, and this was hired at fifty cents a day. The owner of the infested trees, on his way to town to consult a lawyer, met a neighbor who told him not to interfere with his unwelcome visitor who, if an agent of the state, was probably acting under authority of law. This very reasonable but mistaken supposition served our purpose, and no further objection was made, although all assistance was steadily refused. The work was thoroughly done by Professor Summers, and no charge was made by us for materials used. As an example of the cordial spirit in which our propositions were ‘commonly received, Mr. Green’s account of his experience at Manito may suffice. ‘‘Visited, according to instructions, the farm of P. B. Stem, three and a half miles north of Manito. Walked out in the morning and found the owner plowing, He at once put away his horse and showed me the worst infested section of his orchard, spending the rest of the day with me in examining trees and hedges. We found that the scale was scattered through something more than six acres and had also infested twenty rods of hedge. Learning that the soap necessary to thorough insecticide treatment would probably cost about $30, he asked me if I wished the money at once. The next day he hired an additional man for the work and gave also his own time and that of his son. We all worked two days in pruning trees to be sprayed, and afterwards one of us cared for the fire, another worked the pump, and the remaining two 18990. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. 269 applied the spray. Everything I asked was cheerfully done. Trees too seriously damaged for treatment were cut down and burned over their stumps, and a row of osage-orange hedge especially valued by the owner because in a year or two it would yield valuable posts was also cut out by my advice and thoroughly destroyed. Mr. Stem made five trips to town On my account, gave five days’ work of three men, sacrificed about two hundred trees besides the hedge, and put himself to considerable inconvenience in his farming ‘operations, as his teams were left idle when his oats should have been planted.” GENERAL INSECTICIDE PROCEDURE. The field assistants responsible for the spraying of infested orchards were Professor H. E. Summers and Messrs. E. C. Green and R. W. Braucher. Their methods were, of course, substantially the same. When hand sprayers were used the soap solution (two pounds to the gallon of water ) was made in large soap kettles, which it was possible to find in every neighborhood. To diminish the labor and expense, and likewise to insure a more thorough application of the insecticide, trees to be sprayed were pruned and cut back as much as the owner would permit. If the trunks of the trees were rough they were scraped to remove loose bark, and if the scale was found upon the trunk the earth was scraped away to the surface of the upper roots. The assistant always directed the spray himself, depending on the aid of owners for the rest of the work. In distributing the insecticide, limbs and branches were followed out one by one with the nozzle in a way to make sure that the spray reached every portion of the surface. Trees were fre- quently sprayed from opposite directions, especially if the wind were blowing considerably. Trees so covered with the scale that the surface of the bark was generally concealed were commonly cut out and burned. When the machine sprayer was in use two men from my office traveled with it, and two lines of hose were commonly used at once, with two spray nozzles for each. The soap solution was in process of {prepara- tion in one of the tanks while the spraying was emptying the other, and the spraying machine was thus kept continuously at work. For this continuous operation of the apparatus, however, a third;man was re- quired to attend to the engine and make the soap solution. The progress of the work was very much delayed and continuously embarrassed by the unusually wet and open winter. Frequent rains and sleets hindered orchard work or made a repetition of it necessary, and the wretched condition of the roads blockaded the machine.sprayer for “weeks at atime. We also found this large and heavy apparatus incon- venient for our purpose owing to difficulties of railroad transportation. 270 : BULLETIN NO. 56. [ July, It could only be moved on a flat car,—not always to be had at call,— and loading facilities at small stations were sometimes insufficient for the handling of it. These experiences, together with the partial failure of the engine, led towards the end of the season to a substitution of hand equipments entirely for the machine sprayer, three of these being in the field at once during the latter part of our operations. AN EFFICIENT FUNGOUS DISEASE.* Notwithstanding the quantity that has been done and written— much of it by myself—concerning the use of the bacterial and other fungus parasites as a means of spreading contagious disease among in- sects for their destruction, it can scarcely be said that this insecticide method has been reduced to practice with entire success for so much as a single insect species. In the nearest approximation to a practical method yet’ made, the use of Sforotrichum for the chinch-bug, the results have been from the beginning s9 equivocal and so variable that this method has never yet been recommended from this office as gener- ally available or in any way trustworthy. It is with especial satisfaction, consequently, that I now report a series of experiments with a fungus parasite of the San Jose scale, first successfully applied by Prof. P. H. Rolfs, of the Florida Agricultural Experiment Station, which gave in our hands during the summer of 1898 great promise of usefulness as a strong and steady check upon the increase of this orchard pest. The conditions of experimentation with this fungus are fortnieeele very favorable to tangible and precise results. The scale insects being motionless, we are able to keep the identical individuals treated under continuous observation without artificial management; and the fungus used being one not native to the San Jose scale, the results of experi- mentation are not liable to be clouded by its spontaneous occurrence either before or after the experiment is begun. It has been very easy, consequently, to demonstrate the success or failure in every case, and the results may be accepted as unequivocal. The existence of this parasite of the San Jose scale was first brought to my notice by a letter from Prof. John B. Smith, written January 5, 1897, informing me that Professor Rolfs, of Florida, seemed to have found a specific organism which ‘‘had cleaned out some infested orchards in Florida and promised to control the scale completely.” He further quoted Professor Rolfs to the effect that the fungus had with- stood quite a low temperature, and that it was a constant parasite of a scale on the oak. He was also kind enough to send me a small quantity * See Plate IV., Fig. 7, for an illustration of the characteristic growth of Sph@- : rosttlbe coccophila from the edges of a San Jose scale killed by this fungus. NS 1899.]_ WORK ON THE SAN JOSE SCALE IN ILLINOIS. 271 of a culture received from Professor Rolfs purporting to be that of the ‘scale fungus mentioned. The condition of this material from Professor Smith was not such as to encourage attempts at cultivating it, and I obtained instead, direct from Professor Rolfs, early in February, 1898, some limbs of the water oak infested by the common scale of that species, Aspidiotus obscurus, many of which had been killed by the fungus parasite in question— Spherostilbe coccophila Tul. In the letter accompanying this material Professor Rolfs informed me that in order to introduce this fungus into orchards infested by the San Jose scale it was only necessary to tie a piece of a branch bearing the fungus to some portion of the infested tree. February 27th he also sent me a small amount of Spherostilbe on the San Jose scale itself, the product of an infection made by him the preceding year. From the dead oak scales (Asfpidiotus obscurus) received from Florida in February, 1898, cultures of the fungus were. begun March 4th, by my assistant, Ernest B. Forbes, at first on gelatine, then on boiled potato, and finally on corn meal and milk, and corn meal and beef broth. Although the inoculations were all made from the insect itself, all the material proved to be much contaminated, containing especially Penzcelium, Pestalozzia, and a liquefying bacillus. Careful separation cultures were thus necessitated, and by transfer from these, perfectly pure cultures of the Spherostilbe were finally obtained. The arcuate conidial spores of this fungus may germinate within four or five hours, and the growing mycelium acquires a characteristic pinkish color usually within five days. Vigorous growths of the fungus developed identical arcuate spores within a week from the time of in- oculation, this fruiting stage being indicated to the naked eye by the appearance of patches of a deep red color in the lighter pink of the mature mycelium. In one case a culture begun May 17th on bread soaked with sweetened milk, developed spores profusely by May 2oth. It proved extremely difficult to obtain the conidial stage of the fungus, or fruiting bodies of any kind, on peptonized gelatine, and scarcely less -so on boiled potato, but cultures on corn-meal batter made up with beef broth, or on pieces of bread saturated with the same, yielded the spores very readily and in great abundance, the whole infected surface pres- ently becoming a bright scarlet color, and being covered with a thick dense layer of elongate, curved conidia. A considerable amount of moisture seemed necessary to a full development of the fungus, and several of our failures in the beginning were apparently due to the fact that the medium was kept too dry. By May 2tst we had grown a considerable quantity of this fungus \ 292 BULLETIN NO. 56. . [ July, on corn meal and beef broth as a preparation for extensive inoculations. of the San Jose scale in the orchards of southern Illinois. In the meantime a personal visit to the peach and pear orchards of northern Florida gave me reason to expect a favorable result in Illinois, and it likewise put me in possession of a considerable amount of fresh mate- rial in the form of twigs of trees infested by the oak scale killed by the Spherostilbe spontaneous on that insect. My principal observations in Florida were made on the 2oth of March in the vicinity of De Funiak Springs, when, in company with Professor Rolfs, of the Florida Agricultural Experiment Station, 1 care- fully examined three peach orchards. In the first of these, the Rose Hill orchard, there were but very few of the San Jose scale to be found, the number having greatly decreased within the last four years. These trees had been sprayed with rosin, potash, and sulphur during the winter of 1893 and 1894, but had never been artificially infected with the - scale fungus. We found, nevertheless, on a single tree a very few speci- mens of the San Jose scale with a fungus parasite which seemed to be the Spherostilbe coccophila and was so taken by us at the time. Subse- quent study on my return showed, however, that the fungus in this orchard was of a form closely related to S. coccophila, but of a species apparently new. It is distinguished not only by the smaller and much more strongly arcuate conidia, but also by strongly marked culture characters. The color of a mature culture, for example, is not red but a dusky brown with a slightly reddish tinge, and identical culture pro- cesses and media with those which yield the arcuate conidia of Spheros- tilbe coccophila give with this only masses of minute oval spores.” A second orchard, belonging to Mr. Mellish, had originally been heavily infested with the San Jose scale, but this had now almost entirely disappeared. The scale in this orchard had been inoculated in August, 1897, by tying to branches of the infested trees pieces of twigs of the oak bearing the scale fungus. At the time of my visit only a very © few living scales could be found, and among the dead occasionally one still remained with an obvious growth of Sphe@rostzlbe projecting from beneath the edge. This scale fungus was found not only upon trees to which infested twigs had been tied, but upon others adjacent to them, indicating a spread from tree to tree. According to the owner’s statements the surface of many of these trees had been conspicuously reddened by an abundant development of the fungus on the scale, these growths having subsequently been removed, with the dead scales them- * Letters received from Professor Rolfs since my visit to Florida notify me of the frequent finding of this fungus there on the San Jose scale and other species. 1899. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. 27 selves, by exposure to the weather. The trees in this orchard were in very good condition, showing but little effect of the scale attack. The third orchard visited, that of Mr. Thalimer, was in very much worse condition, the fungus having been introduced too late to save many of the trees. The plat contained two hundred and seventy-five peach-trees, three years old, which had become infested two years previously by extension of the scale from the premises of a neighbor. Nine-tenths of the trees in this orchard were dead, according to the owner's estimate, many of them those to which pieces of oak branches had been tied in July of the previous year. Where the trees and the scales upon them were still living, the scale fungus could yet be found _ From the history and condition of these orchards and from other observations made upon this visit it seemed clear that the Spherostilbe could be made useful, especially where for any reason immediate insec- ticide work could not be done, but that it would at best serve only as a strong check upon the multiplication of the scale and not as an efficient means of its complete extermination. I consequently decided to apply it in Illinois on those premises only which we could not reach with the insecticide spray owing to the exhaustion of funds available for this field work. The most important region remaining without insecticide treat- ment was that at Sparta. Some orchards at Richview likewise had been only imperfectly sprayed, and others remained heavily infested and in condition to afford a means of testing the efficiency of this fungus parasite. This scale fungus was distributed to orchards at Sparta and Rich- view by Mr. E. B. Forbes on three separate visits; one from April 30th to May 5th, the second from May 28th to June 7th, and the third on June 23d. Thirty trees belonging to Mr. James Newcome, were thus infected near Richview, and three hundred and fourteen trees, belonging to twenty owners, in the Sparta district, as follows: S. A. Blair, 6 trees. H: A, W. Otten;5 trees: Henry Bodiker, 18 trees. Jefferson Porch, 35 trees Robert Conch, 1 tree. Lowis«Pritz;\s tree: James Davison, 8 trees. J. W. Robinson, 85 trees. Henry Lout, 6 trees. fohne>teel> 7-trees. George Lyons, 4 trees. Jacob Stahlman, 4 trees. Fred Marshall, 1 tree. J M. Temple, 76 trees. John McHenry, 3 trees. Silvenus Wilson, 7 trees. Riley McKelvey, 11 trees. James Wood, Sr., 8 trees. Sidney McKelvey, 2 trees. James Wood, Jr., 26 trees. At the earliest visit only infected scales on pieces of bark or twigs of oak obtained from Florida were used. The twig or bark with the fungus on it was tied to the upper side of a limb, as high up on the 274 BULLETIN NO. 56. [ July, branch as the infestation was severe and in such a position that the southwest rains would readily strike it. From one to a dozen pieces were placed on a single tree, according to the size of the tree and the abundance of the scale, three or four being the commoner number. On the second visit, beginning May 28th, only artificial cultures of Spherostilbe were used, mostly those grown on corn meal or on pieces of bread. About a half inch square of the culture material was softened for a short time with water, and mixed with fifty centicubes of water, and the liquid was spread with a sable brush on the spot selected. The infected spot was then covered by wrapping the branch with a strip of wet duck four inches wide and forty inches long, the wrapping being fastened with a string. These strips were wet a second time on the following morning and were removed in twenty-four hours after appli- cation, the object of this procedure being to keep the culture material continuously moist until the spores had time to germinate. That this was done was shown by the fact that particles of the fungus were generally whitened by a mycelial growth from the germinating spores by the time the cloth was removed. The infected spot was then marked by a white string for convenience in subsequent inspection. The first such visit of inspection was made at Sparta by Mr. Forbes May 27th, three weeks after the infected twigs were put in place. At this time a few dead scales were found in the vicinity of the twigs, but no certain evidence of the spread of the fungus was obtained. On the next inspection, June 21st, a scale dead with Spherostilbe, and showing the fungus in the form of a fruiting growth, was found on a tree to which a corn-meal culture had been applied May 28th. Thecloth wrapping had been accidentally left on this tree, and the fungus had grown under its protection. July 6th, about two months after the first infection of these trees, the fungus had taken effect upon adjacent scales in practically every case where they had been originally abundant and the infection material had been liberally applied, but in no case was the growth on the tree profuse nor even generally visible even on the scales immediately adjacent to the infection material. When only a few scattered scales were present no start had been made. Returning to the same trees September 1st, we found the fungus was by this time growing vigorously everywhere, spreading downward in some cases as far as five or six feet and on lateral branches from the one to which the infection had been applied, as far as a foot beyond thefork. The upward spread, however, was not so great, the spores being evidently disseminated mainly by washing down; and there was nothing to indicate the spread of the fungus across an air space. On one tree six inches in diameter, for example, on Mr. Temple’s place, the fungus had spread downward about two feet, — 1899.] . WORK ON THE SAN JOSE SCALE IN ILLINOIS. 275 as far as the scales extended, and upward not at all. From another piece on the same tree the fungus had spread upward a foot and a half, downward two and a half feet, and thence an equal distance on a lateral branch. From still a third piece it had spread downward three and a half feet and out six inches ona branching twig. Another tree five inches in diameter, to which six pieces of bark had been tied, was so generally covered with the fungus infesting the scales that it was difficult to say whence and how far it had spread. Excepting the smaller and upper twigs and branches, the entire tree was infected. In some places on this tree the lateral spread must have been at least six feet. Another _ tree in this same orchard, to which five twigs had been attached, showed the scale fungus distributed upward from points of infection to distances varying from six inches to a foot, downward from sixteen inches to three feet, and laterally from six to twenty-six inches. The results of infection by means of artificial cultures were equally favorable, and on the whole more marked, owing especially to the fact that pieces of the culture medium remaining on the tree continued to grow the fungus and to produce the spores for an indefinite time. On one tree, for example, the scales on which were infected June 17th by smearing on a thick paste of spores from a culture of broth and corn meal, the fungus had made a visible start by the 5th of July. A few scales were then dead with a noticeable growth of the fungus, and by September rst this growth had become very profuse spreading in various directions from two to four feet from the point of infection. On an- other tree, similarly treated at the same time, the fungus growth Septem- ber 1st (about two and a half months after infection) had become very profuse, extending downward more than six feet and upward about sixteen inches and crossing an air space of at least three feet. The infection material was still growing in good condition and bearing large numbers of spores. On the final visit of the season, made by Mr. E. B. Forbes to Sparta November 2d, it appeared that there had been no great increase in the growth and abundance of the fungus since the September inspec- tion, but that in a number of cases it had spread from limb to limb in such a manner as to suggest that the spores had been conveyed by the blowing of rain drops in a high wind. An occasional washed-out appearance and pale color of the fungus suggested the probability that the recent weather had been too cool and wet for its rapid spread. The fact should be carefully noted that however generally the fun- gus was distributed, it was easy to find everywhere in the infected area scale insects still living and apparently not invaded by it, and even young scales crawling about in considerable number. It remains to be 276 BULLETIN NO. 56. [ July, seen, consequently, how completely even thoroughly infected areas may be cleared of the scale by this fungus, since it is possible that only those scales which were in some way comparatively deficient in vitality were actually destroyed by the parasite. Contrary to this supposition we have only the observations made in Florida, where, again, it is not impossible that other and inconspicuous causes have conspired with the Spherostilbe to reduce the number of the scale. No instance could be found either at Sparta or at Richview of the appearance of the fungus on trees not immediately infected by Mr. Forbes, a fact doubtless due to the hard and tenacious character of the fruiting growth, which is such that the spores of this fungus are little likely to be carried by the air. Doubtless, however, after a time birds and insects passing from tree to tree would effect these transfers accidentally. On the other hand, it is but little work to snip off twigs from an infected tree and tie them to branches of those adjacent, thus securing and has- tening the infection process which a single season should suffice to make general on any badly infested premises. Indeed artificial cultures are so readily made in quantity and capable of being so rapidly applied that it would be a matter of little difficulty to treat a large orchard com- pletely, provided only that the supply of the cultivated fungus could be had by the orchardist. As the cultivation of this fungus parasite requires the expert methods of the bacteriological laboratory, it is beyond the reach of the farmer, who must depend upon the simpler method of infection except where the state or some private expert can furnish the fungus cultures to him as required. Thinking it possible that scales killed by the fungus would be gen- erally removed from the tree, and the dormant fungus with them, by exposure to the winter weather, I took measures to prevent a removal by this means of all the fungus growth upon infected trees by having selected portions of the infected surfaces on each tree wrapped with cloth early in November, to be left on all winter. I have thus made sure that each infected tree will have upon it a considerable area of the fruiting fungus in the spring in condition to renew the infection in 1899. Attempts at infection of the San Jose scale with the new fungus (Microcera sp.) detected in the Rose Hill orchard in northern Florida were not wholly successtul, owing perhaps in part to the small amount of the fungus available for experiment. Applications of a culture made on corn meal and beef broth were so far successful as to infect the scales to which the spores were applied, but there was no considerable spread, in the single experiment made, from the infected area to the adjacent scales. : As aresult of this field work with the above-mentioned fungous 1899. | WORK ON THE SAN JOSE SCALE IN ILLINOIS. CB disease of the San Jose scale it is evident that the distribution of S. coccophila under conditions prevailing in southern Illinois this year is likely to prove a valuable adjunct to more energetic measures for the destruction of this insect. Indeed, we may go so far as to say that if the scale should finally become a permanent resident in this state, it is quite possible that this and similar enemies will forma permanent check upon its multiplication such as to reduce its injuries to comparative insignificance. It must be noted, however, that the summer of 1898 was favorable to the growth and reproduction of this fungus species, both with respect to temperature and rainfall. An abundance of rain- fall was, in fact, shown by my laboratory culture experiments to be indispensable to the profuse fruiting of the fungus, cultures made on a comparatively dry medium often growing freely but remaining sterile for weeks, while those made in a saturated atmosphere would fruit with excessive abundance within four days from the sowing of the spores. In a dry season, consequently, we cannot expect a rapid spread of this fungus from scattered infection points. FIELD NOTES ON FUNGOUS INFECTION. More definite details with regard to the spread of this fungous infection in the field are presented in the following items abstracted from the notes of Mr. E. B. Forbes, the Assistant in charge of the experiments. Neighborhood of Sparta. Orchard of J. M. Temple.—Twigs and bark of oak from Florida bearing infected scales were tied April 30, 1898, to seventy-six trees in this orchard. May 27th, a large number of scales were examined microscopically, but no positive case of death from the fungus was found. t Papas 4 ee 5 4g, << . ’ anak = . =, -* vy ct ‘. = + a POR .. Eats pasivers PLAT KANKAKEE IROQUOIS a oe wh?" Walnlit Prairie t Aho Oyrg® I} MADISON I Summerfield f ST. CLAIR ff Weascouta), @). MAP oj ILLINOIS | Showing IKnown Distribution | fi \ WIN COS SCALE with Extent and Lffeels of Treatment. @lnfested but not Treated. @ Treated but not exterminated. | @ Exterminated. ‘ 1899. | “WORK ON THE SAN JOSE SCALE IN ILLINOIS. ur 20S ‘ Pate II. : | , i F | i | 3 | 286 BULLETIN NO. 56. [ July, PrATE SUL: 1899. | WORK ON THE SAN JOSE SCALE IN PRATe. EV: ILLINOIS. j Pn | eg sae ‘ *% tk é t OS \ ¥ Af : me . 4 ff : s \ f ; Ea } i sae } 3 ? we A Shp. a P me i bea eee - %, ae PARASITES of the SAN JOSE SCALE. 287 | 3 0112 042460615 it Ih