\ THE UNIVERSITY OF ILLINOIS LIBRARY 6*011 1 UNIVERSITY OF ILLINOIS Agricultural Experiment Station BULLETIN No. 185 FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS UNDER THE DIRECTION OF J. C. BLAIE BY B. S. PICKETT O. S. WATKINS W. A. RUTH L. E. FOGLESONG A. J. GUNDEESON TJRBANA, ILLINOIS, FEBRUARY, 1916 CONTENTS OF BULLETIN No. 185 PAGE Introduction 49 Spraying experiments in 1910 at Neoga, Cumberland county 58 Spraying experiments in 1911 at Neoga, Cumberland county 72 Spraying experiments in 1912 at Neoga, Cumberland county 88 Spraying experiments in 1912 at Flora, Clay county 104 Spraying experiments in 1909 at Griggsville, Pike county 118 Spraying experiments in 1910 at Centralia, Marion county 126 Spraying experiments in 1911 at Centralia, Marion county 130 Spraying experiments in 1912 at Anna, Union county 139 Spraying experiments in 1911 at Griggsville, Pike county 156 Spraying experiments in 1912 at Griggsville, Pike county 172 GENERAL SUMMARY Summary of Data 187 Incidental Observations 203 Eecommendations . . 204 FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS INTRODUCTION BY B. S. PICKETT, ASSISTANT CHIEF IN POMOLOGY OBJECTS OF FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS The apple crop is subject to a large number of fungous diseases and to depredations from many insects. In the state of Illinois it commonly happens that the losses from some one or more of these fungi or insects amount to a considerable part or even to the whole of the crop in any one season. According to the Thirteenth Census of the United States, there were in Illinois in 1909, 9,900,627 apple trees of bearing age, producing a total crop of over 3,093,321 bushels. While this low production per tree may be attributed to a number of causes, the most serious single cause for the reduction of the crop is to be found in failure to protect the trees from the ravages of fungi and insects. During the summer and autumn of 1912, a large num- ber of unsprayed orchards in the leading orchard sections of Illinois were visited by the writer, and in no case was there found any fruit fit for barreling, whereas sprayed orchards in the same localities were bearing abundant crops of excellent quality. No one can doubt that attention to this one factor, spraying, in apple growing would easily increase the production of apples in Illinois by 100 percent. The chief insects affecting the fruit of the apple in Illinois are the codling moth (Carpocapsa pomonella), the plum curculio (Conotrachelus nenuphar], and the San Jose scale (Aspidiotus per- niciosus). The foliage is attacked by a number of insects, such as green apple aphis (Aphis mali), canker worm (Paleacrita vernata), fall web-worm (Hyphantria cunea), apple-leaf miner (Tischeria mali- foliella), pistol case-bearer (ColeopJiora malivorella), apple flea-weevil (Or chest es canus), green fruit worms (Xylina antennata et al), and many others. The principal diseases affecting the fruit of the apple are apple scab (Venturia inaequalis), apple blotch (PJiyllosticta soli- taria, E. & E.), sooty blotch (Leptofhyrium pomi, Mont. & Fr.), fly- speck (Leptothyrium pomi, Mont. & Fr.), bitter rot (Glomerella rufo- maculans), and cedar rust (Gymnosporangium macropus). Apple 49 50 BULLETIN No. 185 [February, scab, apple blotch, and cedar rust also attack the foliage. Besides these diseases there is apple-leaf spot, or frog-eye fungus (Spficeropsis malorum), which, tho chiefly destructive to the foliage, occasionally attacks the fruit in the form of black rot. It has long been understood that certain chemicals are destructive to the spores of various fungi ; that poisons of various kinds, but more especially substances containing arsenic, will kill chewing insects; and that certain insects which do not chew their food can be killed by applying some substances directly to their bodies. In order to ascertain the effectiveness of the different fungicides and insecticides which have been advocated or suggested in many quarters, the Horti- cultural Department of this station has conducted experiments on a large scale, under field conditions, using commercial machinery, and continuing the tests from year to year. As a result of these studies, bulletins on the following subjects have appeared: "The Curculio and the Apple," by C. S. Crandall, Bulletin 98; "Spraying Apples, Relative Merits of Liquid and Dust Applications, " by C. S. Crandall, Bulletin 106; "Spraying for the Codling Moth," by J. W. Lloyd, Bulletin 114; "Bitter Eot of Apples," by J. C. Blair, Bulletin 117; "Bitter Rot of Apples," by T. J. Burrill, Bulletin 118; "Bordeaux Mixture," by C. S. Crandall, Bulletin 135. Each of these pieces of work involved a special study of some one phase of apple spraying. In later experiments, therefore, it became the purpose of the depart- ment to coordinate the results of earlier investigations into general systems of spraying, the attempt being made to evolve methods of practice which would be practical from a commercial standpoint and which would effectively apply to the solution of the most important spraying problems. With this idea in view an effort was made to answer the following questions thru the medium of the field experi- ments : 1. What is the general effectiveness of applications of standard spray mixtures, including Bordeaux, lime sulfur, and arsenate of lead, in the control of fungi and insects on the apple? 2. What are the relative values of Bordeaux and lime sulfur as sprays for the apple ? 3. Can Bordeaux injury be lessened or prevented by frequent sprayings with the same spray, or by maintaining over the Bordeaux a coating of lime thruout the season? 4. Is it possible to interchange Bordeaux and lime sulfur, in a spray schedule, to advantage, using Bordeaux for one or more ap- plications and lime sulfur for the remaining applications? 5. What is the most effective and at the same time the most eco- nomical dilution of lime sulfur as a fungicide spray? 6. Is homemade concentrated lime sulfur as efficient as the ordi- nary commercial concentrated lime sulfur ? 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 51 7. What is the fungicidal value of self-boiled lime sulfur, and how does it compare with lime sulfur made in the usual manner? 8. Will the addition of copper sulfate to lime sulfur increase the fungicidal value of the spray? 9. Is an application of lime sulfur made at the strength used for San Jose scale, applied while the trees are dormant, of any value as a preventive of apple scab ? 10. What is the most effective poison which can be advan- tageously combined with standard fungicides for the control of chew- ing insects, particularly the codling moth and the plum curculio? 11. Does arsenate' of lead when used alone possess any fungicidal value ? 12. Does arsenate of lead when added to Bordeaux or lime sulfur increase their fungicidal value? 13. Are there differences between various brands of arsenate of lead which would make one brand more useful than another, either alone or in combination with the standard fungicides ? 14. Of what value are certain new sprays, both as fungicides and as insecticides? 15. How often and at what times should summer sprays be ap- plied ? ORGANIZATION The attempt to answer these various questions for the several lead- ing orchard sections of the state required the organization of the work on a large scale. In order to secure results which would be thor- oly reliable, it was deemed necessary to make field experiments in each of the leading orchard sections ; viz., in the extreme western part of the state, in the extreme southern part of the state, and in the orchard section in the gray-soil region which, in a general way, cen- ters about the counties of Marion, Clay, and Richland. In order to counteract seasonal differences, it was planned to conduct experi- ments in these sections for several successive years, and with one ex- ception this plan was followed. In the results which are given in this bulletin there are presented the data derived from four years ' experi- mentation. In the course of these four years, experiments were car- ried on at five different points, in ten series of plats, in seven differ- ent orchards. Obstacles and difficulties along the following lines presented them- selves in one form or another at various times thruout the experi- mental work: 1. The climatic conditions in different parts of the state vary to a considerable extent, thus making it hard to summarize and average results for any particular season. 2.' It is nearly always difficult to secure orchards of uniformly vigorous growth with trees arranged in such a manner that the vari- eties in each plat will be comparable with those in adjoining plats. 52 BULLETIN No. 185 [February, 3. Uniform conditions in regard to age of trees, slope, and drain- age are difficult to obtain, particularly in conjunction with other re- quirements calling for absolute uniformity. 4. A reasonably uniform infection of diseases or infestation of insects is necessary to insure reliable results, a matter extremely dif- ficult to determine before an experiment is commenced. Certain fungi and certain insects cannot be expected to distribute themselves uniformly, and special methods must be adopted in the arranging of plats and checks to avoid errors in the study of the control of these particular pests. 5. The making of uniform records of experiments in spraying is extremely difficult. Different observers are apt to attach different degrees of importance to the various points on which data are to be obtained. 6. Many things which materially affect results in spraying ex- periments are easily passed over. Successful spraying depends so much upon detail in the correct preparation of mixtures, in the proper agitation of the mixture in the spray tank, in the careful and thoro application to the trees, and on the weather conditions which prevail not only at spraying time but thruout the entire following season, that results may readily be obtained which can be accounted for only in the light of all the conditions prevailing thruout the experiment. The organization for work in these field experiments in spraying apple orchards was designed particularly to avoid or to counteract the difficulties which it was felt certain would be met. Especial care was exercised in choosing orchards which were representative of the sections in which they were located, which were uniform as to variety, age, vigor of trees, and previous soil and spraying treatment, and which were of such size and form as would permit laying out experi- mental plats to advantage. The men in charge of these experiments were all graduates of the University of Illinois, or were trained in the Department of Horticulture at this university. All the men were taught similar methods of preparing the standard spray mixtures used in the experiments and all were familiar with the types of spray apparatus used. The results of the data gathered were freely dis- cussed by all the men concerned, and from year to year, suggestions were made for the better recording of data and for new lines of work. Thus each succeeding year's work has been carried forward in the light of the experience of past years. The accompanying map shows the location of the Agricultural Ex- periment Station at Urbana, and of the various experiments conducted during the last four years. Detailed descriptions of the orchards are given under the reports of each experiment. The following tabulation gives the location of the experiments and the names of the men in charge : 1916} FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 53 CHART 1. — MAP OF ILLINOIS, SHOWING THE LOCATION OP THE AGRICULTURAL EX- PERIMENT STATION AND OF THE VARIOUS EXPERIMENTAL ORCHARDS 54 BULLETIN No. 185 LOCATION OF EXPERIMENTS AND MEN IN CHARGE [February, Year Place County Horticultural division Owner of orchard In charge of orchard 1909 Griggsville Pike Western Central Mr. John Sawdon L. Earl Foglesong 1910 Centralia Marion Southern G. H. Perrine & Sons L. Earl Foglesong 1910 Neoga Cumberland Southern H. A. Aldrieh & Co. O. S. Watkins 1911 Centralia Marion Southern G. H. Perrine & Sons L. Earl Foglesong 1911 Neoga Cumberland Southern H. A. Aldrieh & Co. O. S. Watkins 1911 Griggsville Pike Western Central Mr. G.'Warton Alfred J. Gunderson 1912 Anna Union Southern Mr. F. P. Anderson L. Earl Foglesong 1912 Neoga Cumberland Southern H. A. Aldrieh & Co. O. S. Watkins 1912 Griggsville Pike Western Central Mr. F. Turnbull Alfred J. Gunderson 1912 Flora Clay Southern Mrs. John Egginton W. A. Kuth STANDARD SPRAYS: FORMULAS AND PREPARATION The standard sprays used thruout these experiments were Bor- deaux, lime sulfur, and arsenate of lead. In all cases thruout this bul- letin where the formulas and preparation are not distinctly described in connection with the sprays spoken of, the sprays were prepared as here described. Bordeaux. — Eight pounds copper sulfate, 8 pounds freshly-slaked lump lime, 100 gallons water. Except in the case of the experiments at Flora in 1912, the mixture was prepared by dissolving the copper sulfate in half the total quantity of water used, and mixing the slaked lime with the other half. The diluted solution and the diluted mix- ture were then poured together simultaneously thru a sieve, either into the mixing tank or directly into the spray tank. Lime Sulfur, Commercial, for Summer Sprays. — Eight pounds sulfur in 100 gallons spray (3 gallons commercial concentrated lime sulfur to 97 gallons water, or 3 gallons commercial concentrated lime sulfur in 100 gallons of the dilute summer spray) . Lime Sulfur, Homemade, for Summer Sprays. — Eight pounds sul- fur in 100 gallons spray (5% gallons stock solution homemade lime sulfur to 94i/k gallons water, or 5~y2 gallons stock solution homemade lime sulfur in 100 gallons spray). Lime Sulfur, Homemade, for Dormant Spray. — Twenty-nine pounds sulfur in 100 gallons spray (20 gallons stock solution home- made lime sulfur to 80 gallons water, or 20 gallons stock solution homemade lime sulfur in 100 gallons spray). Stock Solution, Homemade Lime Sulfur. — One hundred pounds sulfur, 50 pounds lime, water to make 66 gallons.1 Homemade lime sulfur was prepared by placing in a large kettle 15 gallons water and 50 pounds good lime, free from air-slaked particles. When the lime was slaking vigorously, 100 pounds of powdered sulfur were poured in, and mixed thoroly with the lime. Sufficient water was added gradually to prevent the lime from drying out during the process of THinois formula. 1916} FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 55 slaking. As soon as the lime was thoroly slaked and the sulfur thoroly mixed, enough water was added to bring the total volume to 66 gal- lons or a little more. Boiling was continued for 30 to 45 minutes, water being added from time to time to keep the rolume at 66 gallons. By following this method it was found possible to get the maximum amount of sulfur into solution. In most of the experimental work, the boiling was done in large iron kettles heated over simple outdoor fireplaces constructed for the purpose. In the experiments at Cen- tralia, however, the homemade lime sulfur was obtained from the cooking plant of G. H. Perrine and Sons. Arsenate of Lead. — Four pounds arsenate of lead paste in 100 gal- lons water, Bordeaux, or lime sulfur. The arsenate of lead was worked up with a small quantity of water into a mixture that would pour readily and mix evenly with the water or fungicide when subjected to the action of the agitator in the spray tank. TIMES OP APPLICATION Thruout this bulletin applications are spoken of as dormant-tree, or winter sprays, and first, second, third, fourth, fifth, and sixth sum- mer sprays. The dormant-tree, or winter, application, refers to the spray ap- plied particularly for the control of San Jose scale, and always con- sists of lime sulfur at the dilutions mentioned under the preceding section. It may be applied at any time after the trees shed their leaves in the fall and before the buds show green in the spring. Usually, however, this application is made during March. The summer sprays are not, strictly speaking, summer sprays, as the first three are usually applied during April and May. They are referred to as summer sprays as a matter of convenience, because all are applied after leaf growth has started. The first of these is com- monly referred to as the cluster-bud spray, because it is made after the cluster buds open and the individual flower buds within the clus- ter buds have separated slightly from each other. The second spray is made immediately after the fall of the petals and while the lobes of the calyx cups are still distended. At this time the calyx cups point upward or outward rather than downward. The third summer spray is made about ten days after the second. Later summer sprays are made for the control of the second brood of codling moth, for bitter rot, and, in some cases, for apple blotch. The spray for the second brood of codling moth is applied from July 1 to 10 in the extreme southern portion of the state, from July 4 to 12 in the apple region included in Marion, Clay, Richland, and adjoining counties, and from that time until the middle of August at the extreme northern part of the state, depending somewhat upon the season. 56 BULLETIN No. 185 [February, Sprays for bitter rot are commenced during the last week in June, if the disease is anticipated, and continued at intervals of ten days until four applications have been made. If a separate spray is re- quired for apple blotch, it may be applied ten days to two weeks after the third regular summer spray, or about four weeks after the fall of the petals. TERMINOLOGY ; DEFINITIONS ; MISCELLANEOUS EXPLANATIONS Bordeaux. — The term "Bordeaux" is used thruout this bulletin in place of the term heretofore applied, viz., Bordeaux mixture. The authors feel that in connection with the literature on spraying the term is now so well understood that there is no necessity for the use of the longer name. It must, moreover, be used with so great fre- quency in a publication of this kind that the omission of the word "mixture" may be justified on the ground of convenience. Combined Fungicides and Insecticides. — When Bordeaux, lime sulfur, or other fungicides have been used in combination with arsen- ate of lead or other insecticides, the names of the insecticide and the fungicide are written consecutively without separation by means of a hyphen or other punctuation ; as, Bordeaux arsenate of lead, and lime sulfur arsenate of lead. Bordeaux Injury to Foliage. — Bordeaux injuries to foliage may be in the form of a yellowing of the leaves, or in the killing of por- tions of the leaf which turn brown and become dry. These dead patches appear along the margins of the leaves or near their tips, where the spray mixtures accumulate in considerable quantities, or in spots distributed over the leaf.1 Yellow-Leaf. — Trees affected by yellow-leaf show premature yel- lowing of the foliage. Usually only a comparatively small number of the leaves lose their color, but in severe cases one-fourth to one- third of all the foliage is lost. In most cases the injury is directly traceable to the use of Bordeaux as a spray ; occasionally it seems to be due to some physiological cause not well understood. When it is caused by Bordeaux the leaves do not turn yellow immediately upon the application of the spray. The injury becomes noticeable in from one to two weeks after the application of the fungicide, or appears even after an interval of several weeks. Lime-Sulfur Injury to Foliage. — Lime sulfur appears to kill patches on the margins of the leaves or near their tips, but yellowing of the foliage as a result of the use of lime sulfur does not occur. Lime-Sulfur Burn or Scald. — Apples sprayed with lime sulfur, particularly during extremely hot weather, suffer occasionally from a form of injury known as burn, or scald. This injury appears on the sunny side of the fruit, frequently toward the stem end or in the 'Bordeaux Mixture, C. S. Crandall, 111. Agr. Exp. Sta. Bui. 135, p. 220. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 57 cavity, if the cavity is exposed to the sun. The injury takes the form of a browning of the skin and of the tissues immediately beneath the skin. It may even extend to the center of the apple. In severe cases the affected part of the apple splits across, sometimes in both direc- tions, forming a cross-shaped incision. When the injury is only su- perficial, it sometimes heals beneath the injured skin, which sloughs off as the new epidermis grows just beneath it and displaces it. Thru- out these experiments lime-sulfur burn was common only during the extremely hot summer of 1911 ; during the seasons of 1910 and 1912 it was- recorded but rarely. Russeting of the Fruit. — "Russeting" is a term descriptive of the appearance of portions of the skin of apples which normally should be smooth, and red or yellow in color. The apple may be affected in varying degrees of severity. In the milder forms russeting appears as a few fine russeted lines which spread themselves in a sort of net- work over larger or smaller parts of the surface of the apple, or it may appear as small black dots which give to the skin of the apple a rough appearance and feel. In cases of moderate severity russeted patches of considerable size appear on the fruit, with lines of russet- ing spreading out from them. Very severe russeting may cause de- formed fruits and render the crop worthless except for bulk or cider stock. Russeting appears to be caused by any irritation to the skin of the fruits. It very frequently follows the application of Bordeaux and other sprays to which copper sulfate has been added. It is also recorded as occurring to some extent after applications of lime sulfur ; not infrequently it is observed where no sprays whatever have been applied. ARRANGEMENT OF SUBJECT MATTER The data for each series of field experiments in spraying are given in separate reports. It will be noted that there is a decided similar- ity between the results from the various series, but it is not to be expected that each series will in every detail corroborate the results of every other series. The data are presented, therefore, with suffi- cient detail to show the scientific accuracy of the work and at the same time to make the results of permanent value, both to the commercial orchardist and to the investigator interested in studying the problems of insect and fungus control from either a practical or scientific stand- point. In addition to a summary which is generally made at the end of each report, a final summary at the end of the bulletin brings together the general results of the four years' experimentation and includes recommendations for spraying practice in Illinois apple orchards. 58 BULLETIN No. 185 [February, BY O. S. WATKINS, ASSOCIATE IN HORTICULTURAL CHEMISTRY OBJECTS During the summer of 1910, spraying experiments were under- taken at Neoga, Illinois, the chief lines of investigation being tests to determine: (1) the relative efficiency of lime-sulfur mixtures and Bordeaux; (2) the efficiency of Bordeaux and milk of lime in reduc- ing Bordeaux injury; (3) the comparative values of various commer- cial arsenates of lead. On a fourth group treatment was begun to test the value of certain new and proprietary sprays, including Pyrox, Sulfocide, Cucasa, arsenic sulfid, copper ferrocyanide, and Black Leaf 40, but owing to unfavorable weather conditions, no fruit data were obtained on any of the plats in this group. LOCATION AND DESCRIPTION OF ORCHARD The orchard selected for these experiments is situated two miles southwest of Neoga and is owned by H. A. Aldrich and Company of that town. It consisted of twenty acres of several varieties of trees, of which three hundred fifteen-year-old Ben Davis trees planted in a solid block were chosen for the experiment. The land upon which the orchard is located is more or less rolling, and a small stream passes thru it. The trees were in vigorous condition, having been given ex- cellent care ever since they were planted. ARRANGEMENT OF PLATS The experimental block was divided into plats of four to six trees each, and the various plats were sprayed differently. Scattered among the plats, check trees, which were given no treatment, were kept for comparison with the sprayed trees. Problems of similar nature were grouped together, and in no group were there more trees than could be sprayed in a single day. APPARATUS AND MATERIALS All spray mixtures were made according to the methods recom- mended by the Illinois Agricultural Experiment Station, and are given in brief under the several groups. Owing to the large number of different sprays which were used and the small amount of each which was required, the material was applied by means of a barrel pump at 100 to 125 pounds pressure. Vermorel nozzles were used. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 59 oooooo oo oooooooo 00 oooooo OOOOOOOO opo^o OOOOOOOOOo® OOOOOOOOOoo _ a « PC o y v 5 i i O 60 BULLETIN No. 185 [February, CHARACTER OF RECORDS AND METHOD OF MAKING Foliage notes were taken from time to time thruout the season, and the dropped apples were counted and examined. All fruit upon the trees at harvesting time was hand-picked, counted, and weighed. Owing to the generally small yield of fruit, practically the entire crop was examined. On a few plats certain trees bore a full crop, and in such cases, a representative tree was chosen, and all the apples on a certain portion of it, including those on the lowest and uppermost branches and those on the outermost and innermost branches of the tree, were picked and placed on the sorting table. From these, two samples of one hundred each were chosen and examined separately and the records compared. In case the records were not approx- imately the same, another sample of one hundred apples was selected and examined, and this process was repeated until the records were obtained upon an average sample. The results recorded are the aver- age of all samples examined. In examining the apples for blemishes, a record was kept of all markings, however small; in grading the standard adopted by the Illinois State Horticultural Society was adhered to.1 The grade rec- ords were taken from the samples examined, and the percentages are based on the number of apples in each grade. This makes the per- centage of No. 2's and culls somewhat larger than would be the case had the grading been in terms of bushels. WEATHER CONDITIONS The season was quite abnormal. March was a warm month, and as a result the trees came into blossom early in April, nearly a month before the average normal blooming date. A very heavy bloom was followed by an excellent set of fruit, but on April 23, when the apples had reached the size of hazel nuts, many of the small ones were frozen. Perhaps 15 to 20 percent of the crop in the experimental orchard survived the cold. The season was normal as regards rain- fall, seldom more than ten days intervening between rains of one-half inch or more. DISEASES AND INSECTS The infection of apple scab could not have been worse, altho the fungus did not appear until about the middle of May, when the apples "'For Ben Davis, a No. 1 apple shall not be less than 2y2 inches in diameter, shall be practically free from action of worms, or not over 10 percent of the apples affected by scab or other defacement of surface; shall be hand-picked from the trees and not bruised, or skin-broken; shall be of a bright and normal color and shapely formed. No. 2 apples may be 2^4 inches in diameter, and not over 20 percent of the apples affected by defacement of surface by dry rot, scab, worms, or other defects; shall be hand-picked from the trees and not bruised or skin- broken ; shall be of a bright and normal color and shapely formed. Adopted December 17, 1903." 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 61 were the size of hickory nuts. There was also an abundance of insects. Neighboring orchards which received no care produced no fruit and were defoliated before the first of September. SPRAY DATES The entire orchard was given a winter application of lime sulfur the latter part of March, just as the buds were beginning to swell; and from one to six summer applications of various sprays were made upon or near the following dates : April 7, April 26, May 10, May 27, June 21, and July 22. RELATIVE EFFICIENCY OF LIME SULFUR AND BORDEAUX During the last few years lime sulfur has attracted attention as a fungicide for the summer treatment of apples. In order to deter- mine the adaptability of this spray for Illinois orchards five plats, each consisting of sixteen trees, and subdivided into plats of four trees each, were sprayed as follows: Plat A: Homemade lime sulfur. This was made by boiling together, until all the sulfur was in solution, 10 pounds of lime, 20 pounds of sulfur, and about 13 gallons of water. This solution was then diluted so that 100 gallons of spray contained 8 pounds of sulfur.1 The material was made up immediately before each application. Plat B : Home-concentrated lime sulfur. This was made by boiling together, until all the sulfur was in solution, 50 pounds of lime, 100 pounds of sulfur, and 50 gallons of water. This solution was diluted so that 100 gallons of spray contained 8 pounds of sulfur.2 The material was prepared early in the season and kept as a stock solution, some of it being used for each application. In order to deter- mine whether or not there was any deterioration of home-concentrated lime-sulfur solution upon standing, the records obtained upon the fruit in these plats were compared with those from the A plats. Plat C: Self -boiled lime and sulfur. This was made from 32 pounds of lime, 32 pounds of sulfur, and 200 gallons of water. The preparation of this spray differs from that used on Plats A and B, in that the only heat used to cook it is that furnished by the slaking lime. Plat D : Commercial lime sulfur, 1 in 35. Plat E : Standard Bordeaux, 8-8-100. For the control of chewing insects, arsenate of lead was added to each of the above mixtures at the rate of 4 pounds per 100 gallons of spray. EFFECT ON FOLIAGE The early effects of the first three applications were quite similar. The first infection of scab did not occur until several days after the third application of spray had been made. Shortly after this appli- cation, there was considerable rain, which washed off much of the spray and at the same time afforded excellent conditions for the germ- ination of scab spores. At the time the scab appeared there was very 1Based on analyses of similarly made solutions. 2Based on analyses of solutions used. 62 BULLETIN No. 185 [February, little spray material visible upon any of the trees which had been sprayed with the lime-sulfur mixtures, while there was a large amount visible on the trees in Plat E, which had received Bordeaux. Plats A, B, C, and D were almost as badly infected with scab as were the check trees, whereas Plat E showed very little scab. With the exception of the self-boiled lime and sulfur, the later applications of the lime-sulfur sprays checked to a considerable ex- tent the work of the scab, but at the same time caused much foliage injury. This injury was along the edges and at the tips of the leaves and in the scab spots; the later the application the more severe was the injury. The influence of the self -boiled lime and sulfur in the control of scab was very temporary; however, no spray injury fol- lowed its use. Bordeaux proved very adhesive, controlled the scab almost perfectly, and caused but little foliage injury. Of the five sprays used, Bordeaux proved the most efficient in protecting the foliage from scab, and self-boiled lime and sulfur the least effective. All the cooked lime-sulfur sprays possessed considerable fungicidal value, but because of their lack of adhesiveness their action was only temporary. In spite of the fact that self -boiled lime and sulfur possesses very little fungicidal value in the control of apple scab, the plat sprayed with this material (Plat C) deserves special attention because of the fact that the general appearance of the trees at a distance was much better than that of any of the others under consideration. These trees were distinguished by the large size, the dark color, and the abundance of their foliage. They did not suffer so severely from the freeze as the others, since the application of lime and sulfur made April 22 formed a coating over the fruit and foliage which acted in some way as a shield against the cold. EFFECT ON FRUIT On all plats some fruit survived the freeze of April 23 except on Plat E, upon which Bordeaux had been used. As this plat was sit- uated in the western part of the orchard, adjoining an open field, only a very few apples escaped being frozen. Table 1 shows the relative fungicidal value of different lime-sulfur sprays in the control of scab on the fruit, and also the benefits de- rived from three, four, five, and six applications. These results fully corroborate those secured upon the foliage, as stated above. Unfor- tunately there were no Bordeaux-sprayed apples directly comparable with the fruit sprayed with lime sulfur, but judging from the effect of the Bordeaux upon the foliage, much less scab might be expected upon the fruit sprayed with that material. The apples from the B plats (sprayed with home-concentrated lime sulfur) showed somewhat less scab than those from the other plats, but even upon these the amount 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 63 TABLE 1. — EFFECTS OF LIME SULFUR, SELF-BOILED LIME SULFUR, AND BORDEAUX IN COMBINATION WITH ARSENATE OF LEAD, IN THE EXPERIMENTS AT NEOGA, 1910 CO Percentage of picked oH apples affected by Plat Treatment Applications ^H * o *3 W) .35 .. "o « ft w i— i o • EH "o § M 0 S § U so u u PH A, 10-20-13 lime sulfur di- 1,2,3 139 94 16 3.6 13 A, • luted 1 in 18 with 4- 1, 2, 3, 4 33 81 24 3.0 18 A, 100 arsenate of lead. 1, 2, 3, 4, 5 42 60 17 2.5 10 A< 1, 2, 3, 4, 5, 6 77 32 24 2.6 5 •*"*-4 B, 50-100-50 lime sulfur J 7 ) J 7 1,2,3 96 68 25 4.0 13 Ba diluted 1 in 28 with 1, 2, 3, 4 140 39 15 2.8 15 B3 4-100 arsenate of lead 1, 2, 3, 4, 5 237 45 19 4.0 14 B4 1, 2, 3, 4, 5, 6 140 15 15 2.7 7 c, 32-32-200 self-boiled *J J > ? J 1,2,3 438 98 38 8.0 8 c, lime and sulfur with 1, 2, 3, 4 323 96 16 0.0 10 c, 4-100 arsenate of lead 1, 2, 3, 4, 5 510 98 16 2.0 6 C4 1, 2, 3, 4, 5, 6 660 100 29 4.0 19 ^4 Commercial lime sulfur j.j **j LFJ j-j r^j v* 1,2,3 343 87 26 1.0 10 vt diluted 1 in 35 with 1, 2, 3, 4 160 73 32 5.0 8 4-100 arsenate of lead 1, 2, 3, 4, 5 127 55 22 0.0 9 D! 1, 2, 3, 4, 5, 6 203 60 35 3.5 10 •*X4 8-8-4-100 Bordeaux ar- / 7 7 7 7 1,2,3 E! senate of lead1 1, 2, 3, 4 O-JJ E, > ? > 1, 2, 3, 4, 5 •"S E4 J J J ? 1, 2, 3, 4, 5, 6 4 Check No treatment J 7 7 7 7 none 210 100 100 28.0 20 *A11 the fruit on Plat E was lost by freezing. was exceptionally large. It must be understood, however, that the general infection that year could not have been worse, for the check trees, which received no spray, yielded no sound fruit and lost their foliage early in September. In order to have any picked fruit for examination from the unsprayed trees, it was necessary to gather it three or four weeks before the fruit on the sprayed trees was ready to harvest. At that time many of the apples were rotting on the check trees, and nearly all of them were deformed and undersized. Much of the injury shown in the russet column was no doubt caused by the cold weather. An examination of the codling-moth injuries shows that the action of the arsenate of lead in the control of this insect was about the same when used in any of the four sprays. It would appear from these data that none of the lime-sulfur sprays used was efficient in the control of apple scab in this particu- lar season. If the danger of spray injury could be eliminated, any of 64 BULLETIN No. 185 [February, the cooked solutions might prove efficient when only light attacks of scab are experienced. Under no conditions would it seem wise to use self-boiled lime and sulfur for diseases of the apple. EFFICIENCY OF BORDEAUX AND MILK OF LIME IN REDUCING BORDEAUX INJURY In 1905 the Illinois Agricultural Experiment Station began an in- vestigation to determine the cause of Bordeaux injury, and, if possi- ble, to find a remedy for it. Among the treatments which gave the most promise of reducing this injury was the after-spray with milk of lime ; that is, the following of the regular Bordeaux application, as soon as dry, with an application of milk of lime.1 In order to determine if this could be accomplished on a commer- cial scale, the following treatments were given seven plats, arsenate of lead being included in each, 4 pounds to each 100 gallons: Plat 11: Milk of lime alone. This treatment was given in lieu of the regular sprayings with Bordeaux in order to determine the effect of lime alone. Plat 12a: Three applications of 6-6-100 Bordeaux, each followed as soon as dry by 8-100 milk of lime. In place of the fourth regular spraying with Bor- deaux, milk of lime was substituted. Plat 12b: The same applications as those given Plat 12a with one additional application of Bordeaux followed with milk of lime. Plats 13a and 13b: The same applications as those given Plats 12a and 12b, respectively, except that 8-8-100 Bordeaux was used. Plat 14: The first three regular applications of 8-8-100 Bordeaux, the third followed by milk of lime. Plat 15: The first three regular applications of 8-8-100 Bordeaux. Plat 16 : Four applications of 8-8-100 Bordeaux, the second, third, and fourth applications being followed with 8-100 milk of lime. An extra application of 8-100 milk of lime was given four weeks after the third application of Bordeaux and three weeks before the fourth. Plat 17 : This plat received the first three regular applications of 6-6-100 Bor- deaux. EFFECT ON FOLIAGE Early in the season Plat 11 had an abundance of large healthy leaves, but as the season advanced the injuries from fungous diseases and from insects became as severe as upon the check trees. Plats 12 and 13 were in excellent condition thruout the entire season. There was no foliage injury of any kind, and the applications of lime ma- terially increased the adhesiveness of the Bordeaux. There was no noticeable difference between the actions of 8-8-100 and 6-6-100 Bor- deaux. Plats 14, 15, and 17 suffered so severely from the freeze that they never fully recovered from the effects of it. The amounts of scab and JC. S. Crandall, 111. Agr. Exp. Sta. Bui. 135, p. 280, 1909. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 65 insect injury were quite small for all plats, and very few yellow leaves appeared on any of them. Plat 16 recovered from the effects of the freeze quite rapidly. The trees of this plat were well coated with the spray material at the time of the freeze, and since adjoining trees sprayed only with Bordeaux suffered severely, due credit must be given the lime for the part it played in shielding them. EFFECT ON FRUIT On those trees receiving applications of lime before the freeze, considerable fruit escaped being frozen. The examination of this fruit gave the results presented in Table 2. TABLE 2. — EFFECTS OF USING MILK OF LIME IMMEDIATELY AFTER APPLYING BORDEAUX OF VARYING STRENGTHS AND BORDEAUX WITHOUT MILK OF LIME, IN THE EXPERIMENTS AT NEOGA, 1910 Plat Treatment Applications • Q d'H. «& .2 ^3 II «iH Cfc Percentage of picked apples affected by & 8 CO Curculio 6C £% 73 a o a O 3 M 12a 12b 13a 13b 16 17 6-6-4-100 Bordeaux ar- senate of lead 1,2,3 1, 2, 3, 4 1, 2, 3, -, 5 1, 2, 3, 4, 5 1,2,3 1, 2, 3, 4 1, 2, 3, -, 5 1, 2, 3, 4, 5 1, 2, 3, -, 5 2, 3, 4, 5 1,2,3 688 530 881 249 366 94 5.3 5.2 2.0 0.0 6.0 5.2 18.4 16.7 2.0 3.0 26.0 30.8 1.5 4.5 1.0 0.7 6.0 6.3 15.3 15.2 11.0 6.7 12.0 25.5 Milk of lime used 6-6-4-100 Bordeaux ar- senate of lead Milk of lime used 8-8-4-100 Bordeaux ar senate of lead Milk of lime used 8-8-4-100 Bordeaux ar- senate of lead Milk of lime used 8-8-4-100 Bordeaux ar- senate of lead Milk of lime used 6-6-4-100 Bordeaux ar- senate of lead NOTE. — Plats 11, 14, and 15 yielded too little fruit to justify comparison with the other plats. It will be seen by comparing, under the column, ' ' Total no. picked apples, ' ' the plats in which the Bordeaux was followed by the milk of lime and Plat 17, in which only Bordeaux was used, that the applica- tion of milk of lime had a decidedly beneficial effect in protecting the apples from the freeze. There is also no doubt that the after-spray of milk of lime prolongs the efficiency of the Bordeaux arsenate of 66 BULLETIN No. 185 [February, lead by increasing its adhesiveness. Altho the difference in the per- centage of scab between the plats sprayed with 6-6-100 and with 8-8-100 Bordeaux, as used in Plats 12 and 13, was not great, there was a slight advantage in favor of the 8-8-100 Bordeaux. There was also a slight advantage in the use of arsenate of lead in preventing curculio and codling-moth injuries. Moreover, it appeared that the after-spray with lime had a tendency to reduce the amount of russet- ing, as in all plats in which the lime was used, the amount of russet was considerably less than where the Bordeaux arsenate of lead alone was used. However, such a conclusion based upon these data should be considered tentative, since much of the russet might have been due to the cold weather. CHEMICAL ANALYSIS OF SOME COMMERCIAL BRANDS OF ARSENATE OF LEAD Arsenate of lead has been one of the leading insecticides for use in combating chewing insects for a number of years. Within the last few years, commercial manufacturers have made and offered for sale prepared arsenates of lead, about which many requests for informa- tion have been received at this station. The brands which were found upon the market in this state in January, 1910, were collected and analyzed, with the results presented in Table 3. TABLE 3. — CHEMICAL ANALYSES OF COMMERCIAL ARSENATES OF LEAD Perc entages Brand A s received Moisture free Moisture Lead oxid Arsenic oxid Lead oxid Arsenic oxid Soluble arsenic oxid Sherwin-Williams. . Grasselli 48.18 40.20 35.77 39.52 12.76 16.29 69.02 66.08 24.62 27.07 All less than % of 1 Star 40.20 40.99 16.95 68.54 28.34 percent Niagara 42.05 38.42 16.70 66.29 28.81 Blanchard 32.96 43.05 19.71 64.21 29.40 Disparene 51.08 31.19 14.97 63.75 30.60 Swift 45.56 3553 1704 65.26 31 31 Hemingway 39.05 37.96 19.15 62.28 31.41 Bex 46.41 33.82 17.13 63.10 31.96 Target. . 4150 3596 1893 61.46 3235 Eagle 47.75 34.12 17.05 65.30 32.63 Vreeland 43.22 35.53 19.25 62.57 33.90 Vreeland powdered trace 62.70 33.76 62.70 33.76 These arsenates of lead were purchased directly from the manu- facturers, and were all received in the form of pastes, with the excep- tion of Vreeland powdered. An examination of the results of the analyses shows an appreciable variation in the composition of the dif- ferent samples, the percentage of arsenic oxid ranging from 12.76 in Sherwin-Williams to 19.71 in Blanchard, and the lead oxid from 31.19 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 67 in Disparene to 43.05 in Blanchard. The amount of soluble arsenic oxid is shown to be quite low in all samples. Calculated on the dry basis, there is a variation in arsenic oxid from 24.62 to 33.90 percent, and in lead oxid from 61.46 to 69.02 percent. Chemically speaking, there are a number of different arsenates of lead, but there are only two which are used commercially,1 the tri- plumbic arsenate, represented by Pb3(As04)2 and commonly called neutral or ortho arsenate of lead, and plumbic hydrogen arsenate of lead, represented by PbHAs04 and commonly called acid arsenate of lead. Most of the above samples are a mixture of these two ; in some the neutral predominates, while in others there is more of the acid. Only one, Sherwin-Williams, showed the arsenic oxid and lead oxid in the proportions to form the triplumbic arsenate. As arsenic is the ingredient in arsenate of lead which gives it value as an insecticide, the above analyses show that the manufacturers, as a rule, have at- tempted to put out products containing the maximum amount of arsenic. In order to obtain reliable data upon the comparative values of the different arsenates of lead, it was deemed necessary to test them in the field. Since it was impossible to try all of these which were analyzed, a few representative ones, based on analyses, were selected. These were tested in two groups, in one of which they were applied with Bordeaux, and in the other of which they were applied with limo sulfur. COMPARATIVE VALUES OF VARIOUS COMMERCIAL, ARSENATES OF LEAD WITH BORDEAUX The following arsenates of lead, all in paste form with the excep- tion of Vreeland powdered, were applied with 8-8-100 Bordeaux, 4 or 6 pounds being used to each 100 gallons as indicated : Plat 6 : Sherwin-Williams 4-100 7: Sherwin-Williams 6-100 10 : Vreeland powdered 4—100 14: Grasselli 4r-100 20: Grasselli 6-100 21: Lion 4-100 22 : Lion , 6-100 23 : Vreeland 4-100 24: Vreeland 6-100 25: Hemingway 4—100 26: Hemingway 6-100 27: Star 4-100 28: Star 6-100 29 : Eagle 4-100 30: Eagle 6-100 'U. S. Dept. Agr., Bur. of Chem., Bui. 131, p. 17. 68 BULLETIN No. 185 [February, Owing to a delay in the receipt of Hemingway and Sherwin-Wil- liams arsenates of lead, Plats 6, 7, 25, and 26 did not receive the first application ; otherwise, the first three regular applications were given to all plats. These plats all suffered severely from the freeze. EFFECT ON FOLIAGE Very little could be determined from the foliage, as insect in- juries were practically the same on all plats. EFFECT ON FRUIT On a number of plats so few apples survived the freeze that the fruit was not worth consideration. Table 4 shows the records which were obtained by examining apples from the plats bearing fruit. TABLE 4. — EFFECTS OF VARIOUS COMMERCIAL ARSENATES OF LEAD IN COMBINATION WITH BORDEAUX, IN THE EXPERIMENTS AT NEOGA, 1910 Plat Treatment Applications Total no. picked apples Percentage of picked apples affected by Curculio Codling moth 6 7 10 20 21 22 23 Check 4-100 Sherwin-Williams arsenate of lead with 8 8-100 Bordeaux 2,3 2,3 .1, 2, 3 1,2,3 1,2,3 1,2,3 1,2,3 none 694 412 152 228 204 398 345 210 35 20 36 30 52 68 60 100 7 6 8 2 8 4 18 28 6-100 Sherwin-Williams arsenate of lead with 8-8-100 Bordeaux 4-100 Vreeland powdered arsenate of lead with 8-8-100 Bordeaux 6-100 Grasselli arsenate of lead with 8-8-100 Bordeaux 4-100 Lion arsenate of lead with 8-8-100 6-100 Lion arsenate of lead with 8-8-100 6-100 Vreeland arsenate of lead with 8-8-100 Bordeaux No treatment. . Because of the small amounts of fruit harvested from the plats of this group, no definite conclusions are justified. However, it is inter- esting to note that, as a rule, six pounds of arsenate of lead were not any more efficient in preventing injuries from the codling moth and curculio than four pounds. It is also evident from these data that the first application, which was made just before the bloom, had no influ- 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 69 ence upon these two insects, since Plats 6 and 7, which did not re- ceive this application, showed, from a practical standpoint, the least amount of injury. COMPARATIVE VALUES OF VARIOUS COMMERCIAL ARSENATES OF LEAD WITH LIME SULFUR When arsenate of lead is added to lime-sulfur solution, a chem- ical reaction between the two takes place. The extent and nature of this reaction differs in the case of the different arsenates.1 In order to determine whether or not there was any difference in the action upon the trees due to this variation in reaction, plats were treated as shown in Table 5. The first application was omitted, owing to a delay in the receipt of some of the arsenates of lead. EFFECT ON FOLIAGE Considering the effects on the foliage, lime sulfur in combination with Sherwin-Williams arsenate of lead, as used on Plat 1, gave the best results. This mixture was the most adhesive, permitted the least scab, and caused very little foliage injury. The arsenates of lead used on the other plats acted much alike. The fourth application caused some foliage injury, which was a little more severe upon trees re- ceiving lime sulfur and Hemingway and Star arsenates of lead than upon those which received lime sulfur in combination with the Vree- land brands. Any difference in insect injury to the foliage was too small to be noticed. EFFECT ON FRUIT The trees in these plats withstood the cold fairly well, and recov- ered quite rapidly from all apparent injury. On- all plats some fruit survived the freeze. It was picked and examined October 26, with the results presented in Table 5. The fruit data recorded corroborate the notes taken on the foliage. They show that fruit from those trees receiving lime sulfur combined with the Sherwin-Williams arsenate of lead (Plat 1) suffered the least from scab, curculio, and russet. The next in order is that from trees treated with the Vreeland brands, between which there is little difference, except in the amount of scab. In the prevention of scab, the dry arsenate of lead in combination with lime sulfur (Plat 4) was somewhat more effective than the paste arsenate of lead similarly used. Neither the Star nor the Hemingway brand, in combination with lime sulfur, exerted much influence in the control of scab. Of these two the Star brand was the more efficient in preventing curculio and JC. E. Bradley and H. V. Tartar, Further Studies of the Eeactions of Lime- Sulfur Solution and Alkali Waters on Lead Arsenates. Jour. Indus, and Eng. Chem., Vol. 2, No. 7, p. 328, 1910. 70 BULLETIN No. 185 [February, TABLE 5. — EFFECTS OF VARIOUS COMMERCIAL ARSENATES OF LEAD IN COMBINATION WITH LIME SULFUR, IN THE EXPERIMENTS AT NEOGA, 1910 Plat Treatment Applications o> 5 £ fr PI ft rt * 3* •o be -a a 0*2 — i co fo TH 35 rH co co t- o o 0 o «H II «3 S rH •* rH 10 ^ co 05 oo co CO fl »-fl fi| o o to •«* Oi t~ ko co to i EH 'S, &1 t- rH 1O OO rH tO f_i (M t 4 t i o to ttj to < > ^ ^ ^ ( ^ • •HH ^ •^ "^ Tj* Tj* i i i 5 A ' •* COCO^M" coco^w cvj ciTco" . p 1 1 4 M X 4 ^ 0 •}; o O !3 o O K^g rH -4J < 4 4 1 H M ,4 5j_| rr4 0 o E 'i Sj oo to "S Jd £ rH 2 a § o ; rH « f • 'w 1 o trt ^ 9 •S 3 o «w a I 9 i rH 4 0 S >->r£ I . 1 .2 1 s 3 U 1: S ^ 00 "w u ' OS o o o O 00 £ «3 6 ^ ^T ffi u 1 II I *4 3<3 pffflpq* cfoc? 6 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 77 which were sprayed with Bordeaux arsenate of lead were much better colored than those which received lime sulfur arsenate of lead sprays. SUBSTITUTION OF LIME SULFUR FOR BORDEAUX IN ONE OR Two OF THE FIRST THREE REGULAR SUMMER APPLICATIONS The experiments thus far considered appear to show that Bordeaux for use as a fungicide upon apples is superior to any of the lime-sulfur sprays. However, since applications of Bordeaux are occasionally followed by a russeting of the fruit and a premature defoliation, it cannot be considered an ideal spray. Lime sulfur has been shown to possess certain fungicidal properties, but it has the great disad- vantage, aside from possible injurious effects, of lack of adhesiveness. In order to see if it would be possible to substitute lime sulfur for one or more of the regular applications of Bordeaux, applications were made as shown in Table 7. EFFECT ON FOLIAGE Very little information could be gained from the foliage notes, as the amount of injury of all kinds was small on all plats. Immediately after the third application of lime sulfur arsenate of lead had been made, June 3, the trees receiving it showed some foliage injury, but not enough to be considered important. Ten days later, however, a very serious burning of the fruit developed. EFFECT ON FRUIT The fruit on these plats was picked and examined on October 17, with the results presented in Table 7. These data show that the most satisfactory results were secured when Bordeaux was used for the first and third applications and lime sulfur for the second (Plat 24). Under this treatment there was a very low percentage of scab and no spray injury of any kind ; and only one percent of the apples were culls. The fruit on Plat 22, which received the first and second appli- cations of lime sulfur and the third of Bordeaux, was very good, and differed only slightly from that picked from Plat 24. EFFICIENCY OF BORDEAUX USED IN DIFFERENT WAYS IN REDUCING BORDEAUX INJURY It has been the experience of some growers who are in the habit of drenching their trees when spraying with Bordeaux that very little of the fruit russeted. In order to secure data on this point, a test was made to determine the difference in the amount of russet caused by drenching and by light but thoro applications. Investigations1 have shown that the most severe russeting of fruit caused by Bordeaux is the result of the applications being made shortly after the fall of »U. P. Hedrick, N. Y. (Geneva) Agr. Exp. Sta. Bui. 287, p. 163. 78 BULLETIN No. 185 [February, T3 >» CD -1 9 3 rH 0 rH o rH o o J4 O rrj O CD hnsw 3 M CD rH rH " o rH t- 0 1 * QS S w §5 £ & <3'5o € 9 O CO cq 10 CD co O co O O gS 1— 1 o ^ fr^ CQ OO CO eq co CM CO •* cq CO 00 rH CO cq t- 00 o 00 OS ~ CO »o rH 1? 00 a 0 p 03 a 1 o eq to cq •S 01 6 !25 S PQ CD XI E 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 79 the petals. In continuing the treatments of 1910 made in order to determine the best method of reducing the injury following the use of Bordeaux, four plats were treated as shown in Table 8. EFFECT ON FOLIAGE The fungous and insect injuries to the foliage were so slight in all plats that no differences could be distinguished. The drenching applications made on Plat 34 were much more adhesive than the regu- lar applications made on Plat 35 and seemed to exert a stimulating action. The foliage in Plat 34 was unusually large and vigorous, and of a very dark green color. No yellow-leaf appeared on that plat, and only about 5 percent of the leaves on Plat 35 were so affected. There was no noticeable difference resulting from the treatments given Plats 36 and 37, the general appearance of both being the same thru- out the entire season. No yellow-leaf appeared at any time upon either plat. EFFECT ON FRUIT The fruit from the trees in Plats 34, 35, 36, and 37 was picked and examined October 17. The results, presented in Table 8, show that the heavy application of Bordeaux arsenate of lead was much preferable to the usual lighter application. The efficiency of the mixture was not only greater in controlling scab, but the amount of russeting, for which the spray was no doubt responsible, was much less. The results from Plats 36 and 37 seem to indicate that it matters very little whether the lime follows the second or the third applica- tion. The apples in Plat 37 graded slightly better than those in Plat 36. Since these results are not entirely in accord with those ob- tained in 1910, the subject needs further investigation. LIME SULFUR USED AT VARIOUS STRENGTHS In the preceding experiments where lime sulfur was used, the solu- tion in all cases contained 8 pounds of sulfur in solution in each 100 gallons of spray. In order to determine the efficiency and safety of lime-sulfur solutions of various strengths, plats were sprayed with commercial lime sulfur as shown in Table 9. EFFECT ON FOLIAGE Very little difference was noted in the foliage in the various plats. In each case there was a slight injury following the third application, but in no plat did it prove permanent. 80 BULLETIN No. 185 [February, si §5 Si II K 2 fl '. J 00 h 1 N -<*• IN CM ^ >% OJ ^ 3 M rH *« r^J ac *s ^ ^ J3 M-I-4J '__ 4^ CO (M to r«4 T3 O rH 2? QJ o S ^ 03 o. H g CO o S •— * "3 - p< o O4 Cd OQ o hi PH o3 o Is •fl «O 05 CM t» rH o 00 O5 E-> "a. 03 •* CO 10 00 CO 1 O *p CO eo eo CO 03 ^ ^ ^ ^ •Sn Od CXI CM CM "E. ^ •^ rH- H" "1 1 1 n £ • 03 „ • 03 03 O) 1—1 0 O 03 hi 03 03 03 hi X 1^ ^ « rj 3 to * 0 3 03 03 c8 03 0) • ^ m hi hi rH h> o O O « o PQ pq pq o o 0^3 O *3 o o O & O °* 4 4 41 4| 00 00 00 'oS 00 03 i 1 1 1 00 00 oo 00 Is to 0 K PM CO CO CO CO a 3 -H 0 ,Q o ^ 1 — ^ 3 rH 0 CO rH] CD S | j« 03 hi — • a co A a CO 0 00 •4< S 4S ^1 rH CO CD ^ O *H OH as* ,0 oJ CO to rH 05 Oi eo co *" CO -5 OJ (M O 00 0 -H o CIO to 3 ® CD CD .§ S «rH .§ .§ O O O O rH rH CM i— 1 3 rH ts Od CO « w S "* "* •* 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 81 EFFECT ON FRUIT The records of the fruit, which was picked and examined October 13, are presented in Table 9. The weakest solution used, one gallon of concentrated solution to 50 gallons of water, a spray containing about 21/2 pounds of sulfur per 50 gallons, seemed to be the proper dilution for scab under conditions as they existed during 1911. In this plat there were not only fewer scabby apples, but a larger percentage of No. 1 apples than is credited to any other plat. A noticeable feature was the small amount of injury resulting from the strong solution used on Plat 44. There were in each 100 gallons of spray used on this plat about 16 pounds of sulfur, which is twice the amount generally considered safe for use upon apples. In order to determine the effect of these dilutions in seasons of more abundant rainfall, further inves- tigations are necessary. COMMERCIAL ARSENATES OF LEAD WITH BORDEAUX In 1911 various commercial arsenates of lead were tested in com- bination with Bordeaux, as shown in Table 10. EFFECT ON FOLIAGE Very little could be learned from examination of the foliage as the amount of insect injury to the leaves was unimportant. There were no noticeable differences in the adhesiveness of the mixtures. EFFECT ON FRUIT Table 10 presents the results of the examination of fruit. As in 1910, very little can be determined from the results obtained, since the variation between the different plats was only 7 percent in curculio injury, and but 3 percent in codling-moth injury. The varia- tion in the percentage of russeting may be due in part to the brand of arsenate of lead which was used, as other conditions were the same. COMMERCIAL ARSENATES OF LEAD WITH LIME SULFUR As a further test of the action of the various arsenates of lead when applied in combination with lime sulfur, various brands were added to commercial lime sulfur and tested as shown in Table 11. EFFECT ON FOLIAGE There was some foliage injury on all plats from time to time thru- out the summer, but only in Plat 5, which received Grasselli arsenate of lead alone, was it of a permanent nature. Here there was very little injury until about the middle of September, when the leaves 82 BULLETIN No. 185 [February, -s T3 >» '£ A "* rH rH O eo 00 t- 0 C? f^ PH '*•§ 00 §35§ ?3 o 00 IQ 10' t. t- I, o IQ w 0 in CQ ,^ •2 g •ail o eo eo 00 S o CQ CQ eo •-H co H • S ft oo rH O rH 1C CO § 3 1 CO eo eo eo co eo 1 CvT CQ" M CO* cf CO" § ^ ^ •N ^ ~ - - P 3* O O o •5 •3 o o 3 w 7* '$ '£ rH 1 00 00 o o rH 00 03 T3 oo « 1 ^ 5 ^ «— i oo ••j r-^ •""• -*^ oo •g «w «H '? o o O rrt F^ -- 03 o> •iH oi 03 01 03 ^ ^ "cS O3 O4 P * q 13 1 p O w i o* r 3^ r-l 00 O | rH 00 CQ 3* 0 | rH OO O 4 • •8 1 I 4 rH CQ rH CO rH 3 »o rH rH i 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 83 turned brown along the edges and at the tips. They retained this appearance thruout the remainder of the season, and about 25 percent of the foliage fell prematurely. The materials used on Plats 7, 8, and 9 were slightly more adhesive than those used on the other plats. EFFECT ON FRUIT These plats all had an abundance of fruit, which was picked Octo- ber 24 and 25, and examined with the results shown in Table 11. The most noticeable feature of this table is the variation in the amount of scab. Plats 7, 6, and 3, which were sprayed with Sherwin- Williams, Swift, and Vreeland arsenates of lead, respectively, were least infected with scab, having 16, 18, and 19 percent of scabby apples. Owing to the small amount of insect injury, little can be said as to the comparative insecticidal value of the different brands of arsenates of lead used. There was a varying amount of russet and burn credited to the different plats, but the difference was not great. However, since neither arsenate of lead nor lime sulfur, when used alone, caused any burning, this injury appeared to be due to the re- action resulting when the two are combined. Attention is called especially to the records obtained from Plat 5, which received arsenate of lead alone, and Plat 10, which received lime sulfur alone. It will be seen from these results that both lime sulfur and arsenate of lead when used alone possess some fungicidal value, but that when combined they produce a much more efficient spray. Attention is also directed to the large amount of codling-moth injury recorded against Plat 10 as compared with the check plat, sug- gesting a possible attraction of the codling-moth adults to trees sprayed with lime sulfur. In fact, the fruit in this plat suffered worse from codling moth than any of the check trees thruout the en- tire orchard. Altho the results recorded in the different columns do not show wide variation among the different plats, they are in accord with those obtained in 1910, which showed that, in combination with lime- sulfur solution, the neutral arsenate of lead produced a spray which was more efficient and safer to use than those arsenates of lead higher in arsenic oxid. CERTAIN NEW FUNGICIDES AND INSECTICIDES In order to test the value of lime sulfur arsenate of lead when mixed with copper sulfate and also the value of certain new fungi- cides, various homemade and proprietary mixtures were applied as shown in Table 12. EFFECT ON FOLIAGE All mixtures of lime sulfur arsenate of lead and copper sulfate showed quite plainly upon the trees, and varied in color from dark 84 BULLETIN No. 185 a 1 1-1 iH H 10 * o 10 cq « * o 0 "S1 1 01 W cq <* I-l 1-1 r-l H co i-i oo rH o as 2 -~ -— bo r-l r-i os rH oo 0 00 to to pv Q} £~3 O iH iH cq rH "S o S "S 3 W 0 oo to OS CO rH co IN. eo <• -, « o 03 00 O OS 00 to »o to I-l OS « cq cq r-l CO W 1-1 r-l £> eo 10 -^ 10 cq 10 LO in |*v o to a t^» Tjl ^ OS to t>» o os i-H 00 O a o f** ^i os os CO iH OS CO to CO CO H •p.rt' OS 10 * r-l TH 10 * cq a o CO CO CO CO CO eo co co eo eo 1 _^ 3 r& B eq cq cq cq cq cq cq cq cq cq o c^ Q< r-i o 5 5 03 g 1 T3 03 I ft .s j£ |£ -^ •j a> ^H S £ i-H 03 i O 5 d ft O ja 03 | — H Q? »^ • ^ B fe B • • t*- , E> _4J ^' iC O 8 o 0) a | 03 _QJ "3 03 03 a i o h Treatment 4-100 Vreeland dry arsenat lime sulfur 2-100 Vreeland dry arsenat lime sulfur f E 03 ^3 "3 o> s .§ o5 in O "oS d t+ 03 OJ "bfi 03 H ^ a 03 4-100 Grasselli arsenate of 4-100 Swift arsenate of 1< sulfur 4-100 Sherwin-Williams ar with lime sulfur 2-100 Grasselli arsenate of sulfur 4-100 Hemingway arsenatf lime sulfur B 15 00 I No treatment TE. — Commercial lime sulfu o d r-l cq CO •* 10 to t. oo OS O "1 ^ S 1-1 6 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 85 brown to almost black. Plats 18 and 19 looked very much alike; on Plat 17 the spray showed a somewhat darker brown, and on Plat 20 almost black. Permanent injury from these sprays was negligible, altho for several days after the application to Plat 20 had been made, its foliage presented a scorched appearance. This, however, soon dis- appeared, and thruout the remainder of the season the trees appeared very healthy. There was an abundance of foliage of good size and of a dark green color on all these plats. The mixtures applied were all of about equal adhesiveness and remained visible thru most of the summer. Cucasa, when dried upon the trees, resembled Bordeaux but did not prove quite so adhesive. There was some foliage injury at differ- ent times during the summer on the trees sprayed with this mixture, and about 20 percent of the leaves turned yellow and fell. The ma- terial used was some that was carried over from 1910, and might have been less satisfactory than the fresh product. Copper ferrocyanide is a new spray of considerable promise made from copper sulfate and potassium ferrocyanide. The two salts were dissolved separately, and when poured together produced a flocculent red precipitate of copper ferrocyanide. This mixture gave a red cast to the leaves which was plainly visible. The foliage was quite dense, of good size, much darker green, and glossier than that on any other plat in the orchard. No injury of any kind was noticed at any time during the season. It is thought that this mixture possesses both in- secticidal and fungicidal value, but owing to the scarcity of insect pests and fungous diseases, as well as conditions conducive to foliage injury, the results obtained this year were rather indefinite. The cost of the material at the strength used is about one-third that of lime sulfur arsenate of lead. EFFECT ON FRUIT The recorded data show that of the four sprays used on Plats 17, 18, 19, and 20, made by combining lime sulfur arsenate of lead and vary- ing amounts of copper sulfate, those used on Plats 17 and 19 con- trolled scab exceptionally well. The spray injury as shown by the rus- set and burn columns was negligible. The grading was fairly good for all plats. The results seem to indicate that the mixtures made from lime sulfur arsenate of lead with 4 pounds of copper sulfate and with the Bordeaux arsenate of lead, as used on Plats 17 and 19, respectively, are probably the best combinations. Lime sulfur arsenate of lead with 2 pounds of copper sulfate was too weak to control the fungous diseases properly, and when made with 6 pounds of copper sulfate produced a very bulky precipitate which prevented a thoro coating of all parts of the fruit and foliage. The fungicidal value of Cucasa was almost equal to that of Bor- dfaux; no russeting of the fruit followed its use. -Copper ferro- 86 BULLETIN No. 185 [February, • — & ft * r-l CO 0 o O o o O cs PQ ^fr •» «i P r-l _M '^ ® i-l (M co ^n O 0 t- o 8 s rH 'ftl PH B 03 rH V O 05 *> t- •- bc?H ® ko _« cs -3 9 ro c rH 0 o CO o eo rH o os OS E • 3 P O *H 5 ^ o o 5 « -3 PH § g oo CXI =3 OS (M oo rH W3 00 p .9 02 02 "S (5 • o u CO § o eo t- M T-l (M rt W OS 03 w ^ S"2 ^ >> W 0> 03 OS CO ^ 'f oo IO O es u & **' O MH c 044 ^ r. " .2 ft sn pma 0 s co fci ^ T) > 8 CO o rH 0> i 1 6 JH § • a 03 03 * o *) 5 £ 3 I (D 90 BULLETIN No. 185 [February, WEATHER CONDITIONS The weather conditions of 1912 were very nearly normal. There was a great deal of rain thruout the entire summer, but at no time was it in such an amount or of such duration as to be disastrous for or- chard operations. The harvest season was ideal for taking care of the fruit, as only two days out of several weeks were lost on account of inclement weather. The trees came into bloom early in May. The weather was excel- lent for pollination, and a very good set of fruit resulted. During the latter part of the blooming period a heavy rain occurred, which made conditions very favorable for the development of the apple-scab fungus. At this time scab was first visible upon the foliage, but it was four weeks later that the first scabby apple was detected. The attacks were quite serious at times, but at no time was the fungus active over a very long period, a few bright days generally interven- ing between the stages which were advantageous for its development. The unsprayed or check trees lost most of their fruit and foliage sev- eral weeks before harvest time, and that fruit which remained on the trees till picking time was very scabby and showed considerable insect injury. The codling moth caused very little injury, and altho the curculio did some damage, it was more or less irregular in its attacks. SPRAY DATES All trees which were to receive a winter application were sprayed April 13, with commercial lime-sulfur solution diluted 1 in 15. From one to five summer applications were made upon or near the follow- ing dates : April 27, May 11, May 23, June 25, and August 6. FUNGICIDAL VALUE OF WINTER LIME SULFUR The winter application of lime sulfur has usually been made only on those orchards which are infested with San Jose scale. The bene- ficial effect of such treatment upon the general appearance of the trees has been sufficient to attract attention. It has also been observed that in certain seasons orchards receiving a spraying of lime sulfur for San Jose scale are less subject to severe attacks of scab than adjoining orchards from which the winter treatment has been omitted. In order to obtain data upon the fungicidal value of this treatment, two plats, each consisting of sixteen trees, were subdivided into sub-plats of four or eight trees each and treated as shown in Table 13. EFFECT ON FOLIAGE A small amount of injury to the green tips of the leaves which received the winter application followed the treatment given Plat B. 1916} FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 91 f*3 '*<^ OO CO CO CO ^^ O CM Tj< CO r-J rH g rj-j 3 CO* OJ CN1 rH -i CO' Sf M .*§S ^1 3 "o >C !-H CO 1C CO >C OQ OJ IO 00 t-. •* CM' 10 t-' os' >c oo' H *o ® E-1 CM rH CM rH tM CM cS CD cS ,0 00 M 03 3 CS CO •* OS 00 CO E cS oo ,u .2 OS Tj< -^ OO CO OS «.' W CO' t^ H CO M 5 3 CD ^5 ifi r3 •i "ft B O t- O 1C W 1C O OC t- Tt< O rH t- 1C 0 c8 03 O g 0 rH OS' OO" 00 OS 0] 'C |PQ & ^H rH H CO H C O OO 02 «(H CS 0-S t-' rH CD* SJ' ^ OO' M o rt*i 3 rH rH rH rH rH rH i — _., W ,0 . S OJ S "-1 &S 2 O i_ 1C CM CM rH b- -^ rH rH -* t- >C 0 tuo 02 bo c§ o g O CO t~" -^ CD (M o3 (H < CO W g (M rH rH rH rH (M P< m o tiJD 09 \J §fe s s 0 H J •< ercenta rO r5 ® a "* pq = t>- *"-• O OS t^ 1C O •* !>; 1C CO O -ji O CO rH OS Tj5 t- OO C- 00 l>- t- "3 • § bo HH O 03 PH • g| (6 K gS ga o fc pq°| 10 co L~J •* co oo rH TJ( 1C rH l^ CO Os' ci ro' t~ •*' <» CO t- t- »• t- CO "cs o> a w • H 0) t- s g ^^ *& m "3 p SH 6,5 'p.S -33 OS CO •«*< ° w "w §o 1 ^ rt ^4 "M rH J3 co _oj L . • t_l ** 1 tl A co rH 1 < H I2ll 111 f-K rH OS CO ^^ ^5 rH 00 O OS •* •* »O "S j§ CO i »O Tj* CO »O rH tO b- OS 0> c« PM In ^ IO b- b^ rH O5 8 0 m OO b- CO O IO CO O OS rH rH b- •«* O «> i rt o S rH rH CO O iH OS °0 •a pq g 1 ^ 5 ® fl ® to co >o rt* 10 ^ o to 10 to co oo eg 10 o 01 ee o"S w ^ t-^ CO' CXI b^ rH to CXI C\l rH CXI rH rH r-t i fc "T? 9 p^ rH 00 00 IO CXI Ol O oo eg t- •— i rH -<^ to & «ssl OS to IO O «O b- iH eg I-H eg cxi rH rH 1 Tj m b- IO CO b- b- O O tO 00 b- O •* b- O I A, i-l cS O tn C3 I3 ifi fH OO b- Tj< O ?D tO b- tO b- OO b- fc rC? QJ rH IO •* IO CO IO O eg 10 o rH TJH 10 o | = | oo eg rH os eg co IO b- tO tO t- b- ,o| SO CJ "ft S "S Pi 1 ' O IO IO OS tO "* O OO t- b- !>. OS OS IO 1 CS —i rH eg 3 . a -• t <£ "o 30 Tt< IO OS tO iH O O IO tO eg rH rH tO 5-1 2 c. ^5 ft U c« os oo co 10 eg to rH eg Tti eg co co eg 1 •5 . a = r* 3 _i 'S CO Q> ft 4 cS co to to to b- co o to eg 10 eg o oo o CO IO i— 1 CO CO O TjH 10 oo •<* to to 10 lications 10 W ., ~ - * co co co co co n § ft eg eg eg eg eg N •^ Treatment \ 8-8-4-100 Bordeaux ) arsenate of lead i 1—40-4-100 commer •| cial lime sulfur ( arsenate of lead No treatment 4^ # •^ -^ -«jj CQ CQ 02 ® .'"I 0 94 BULLETIN No. 185 [February, colored than those sprayed with Bordeaux, but after the fruit was placed on the sorting table, it was found that the color on the apples sprayed with Bordeaux was more evenly distributed over a larger proportion of the surface. However, the apples sprayed with lime sulfur were much smoother and presented a better polish, while upon close inspection many of the apples sprayed with Bordeaux showed numerous minute black specks. Records were obtained upon insect injuries and certain fungous diseases, but as the attacks were irregular and have no direct bearing upon the experiment, they were omitted from Table 14, in which the fruit data of this experiment are presented. Considering first the grade columns of Table 14, lime sulfur arsen- ate of lead in 1912 did very effective work, being somewhat better than Bordeaux arsenate of lead. The comparative efficiency of the two mixtures as fungicides is designated by the scab columns. Any difference here is slightly in favor of Bordeaux arsenate of lead, but it is too small to warrant much emphasis. The amount of russet was decidedly small in all plats. The absolute necessity of spraying is shown by a glance at the records of the apples picked from trees re- ceiving no treatment. The use of more than three applications seemed unnecessary at Neoga in 1912, as the variation between the percentages of No. 1 apples in the different plats was neither so regular nor so varied that any definite conclusions might be drawn. EFFICIENCY OF LIME SULFUR ARSENATE OF LEAD SUBSTITUTED FOR BORDEAUX ARSENATE OF LEAD IN ONE OR Two OF THE FIRST THREE REGULAR SUMMER APPLICATIONS For a number of years, Bordeaux has been the standard fungicide for most diseases of the apple. During the last few years, the use in Illinois of lime sulfur as a substitute for Bordeaux has always proved more or less satisfactory, particularly in certain parts of the state. In order to see if a combination of the two sprays might prove effi- cient, that is, the using of Bordeaux for one or more applications and lime sulfur for the others, in an attempt to remove the undesirable qualities of each spray and still have a satisfactory schedule, three plats were treated as shown in Table 15. EFFECT ON FOLIAGE At all times during the season, Plat 4 showed considerably more scab upon the foliage than did any of the other plats. This was espe- cially true before the third application had been made. A small num- ber of yellow leaves formed on the trees in Plats 3 and 4 shortly after the third application, but these soon fell, and no permanent injury of any kind was apparent. Some of the leaves on trees in Plat 1 be- 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 95 < P fcH la H 5 05 P M GO £ 02 g o £ •< w "i -H in U5 O i o o o o 0> [^ s 03 t- ^ ^ ft^ 3 OJ .-i o ira -2 0 oo t>: \n cj o § H rH OQ Oq OJ S>* fi5 i no O •s OJ OJ "^ O CD rH CO IO CO t^ to t-^ ® & M M £?* qj OQ PM -u | OJ CO IO t^» rH O 00 rH rH rH •g -3 t_ 00 TH 0 ao oq iq iq rS O {ft to CO CO t^ 73 S. p rH rH OJ S "3 iS "ft 0 ^y S (M tO 1T5 O • 1 J8! oj CD m j-~ — l^ OS 00 rH rH OJ 'a 1 -1 CO CO O O t~ rH 00 iq o oq l§! PQ 2 t-^ rH OJ OJ rH (M rH CO 6 r§ S Kj Tj< OJ t« O B * O "e OS O ^ lft M cj O S '&} •*& rH rH ® bo « a rH (M — *fQu_i^5^PQu_j'J5 ®pq«tj. g a o cs o "S on -« OS OO oC me 1 1 ^H2c^|t~l2^|^"2c^"cfi l,c3jC^W|Crcg|C^ 1 *H'*:TICG 1 M^Pcn 1 1* ^T ui ^t 03| (-ODI HS Jj J ^ TJH^HOO CS^=HOO CS^SHOO !S o rH on rH on rH on f-> _4J M -2 i-l CO -^ ® fn e 96 BULLETIN No. 185 [February, came brown spotted after the third application, but this was notice- able for only a few days. EFFECT ON FRUIT The fruit upon the trees in these plats made a good appearance, that on Plat 4 being the poorest. The crop was harvested and exam- ined on October 15, with the results presented in Table 15. The use of Bordeaux arsenate of lead for the first application and lime sulfur arsenate of lead for the second and third applications, as in Plat 1, proved the most satisfactory treatment of this group. The trees so treated yielded fewer scabby apples (18.59 percent as com- pared with 27.81 percent and 25.2 percent for Plats 3 and 4) ; and the percentage of No. 1 apples was nearly 20 percent greater than that shown by either of the other treatments. There was a slight vari- ation in color in favor of Plats 3 and 4 over Plat 1. The large amount of russet in Plat 1 compared to the other plats was rather unexpected. The effect of spraying upon the size of the apples may be seen by comparing the number per bushel in the various plats. The unsprayed apples were about 20 percent smaller than the sprayed apples. EFFICIENCY OF ARSENATE OF LEAD WITHOUT A FUNGICIDE FOR THE SECOND APPLICATION Because of the tender condition of the small apples at the time of the second application and the injury occasionally following the use of Bordeaux arsenate of lead at that time, the question is often raised, Is it absolutely necessary to use a fungicide in the second application ? In order to obtain information upon this point, plats were treated as shown in Table 16. EFFECT ON FOLIAGE As the season advanced, there was a very decided difference in the general appearance of the trees in Plats 5 and 6 and those in the other two Plats, C and 10, in which the treatment differed only in regard to the omission of the fungicide in the second application. This difference could be distinguished at some distance, as the foliage in the two former plats was ragged, and about one-half of it fell pre- maturely. The most serious attack of scab experienced was at the blooming period, and by the time the third application of Bordeaux arsenate of lead and lime sulfur arsenate of lead was made on Plats 5 and 6, the foliage of the trees in these plats was so badly infected with scab that considerable injury followed this application. In the case of Plat 5, which received the lime sulfur arsenate of lead, the injury in the form of brown spots in the leaves where the scab spots were, developed within a few hours after the third application. In the case of Plat 6, which received Bordeaux arsenate of lead, no in- 1016] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 97 CO a £ o u H OQ B§ EH ,-H ID W EH Percentage of picked apples affected by -u 1 co co eo rfi rH CO oq i "o EH 1C i-H 1C OS OO CO CO 1C os o t>* eo* rH oq t* ic Serious 00 0 TtJ OS to eo" eo* rH rH tO -^ 1 i to 1— rH t~ os oq os to OJ* . t>* CO* rH rH rH rH Percentage grades of picked apples cc 6 • 0*3 « ^ os ^ oo o 1C oq r-i 1C ^5 <~^ 8 H-S 03 0 S « g 1C t- O Tj< rH oq OS C> CO* 1C tO*- OS I-H ic cq cq 6 _. CD "S PQ 3 O O b- fr- oq* ic o o rH rH O3 CO C3 0 g PQ g rH tO Tff O i>; CO co oq ^ t^" Os ^^ rH rH rH CO 1-1 6 DO M°l »c os to cq oo t— 6q ^ Based on number rH 00 b- b-; b-" td CO* O b- to oq T* . 1> S "® p, EH "jx, ci rH 0 TfH OQ TjH OS I— 1 1C o - w 02 't-l O* CO* CQ* O* rH Tjf CO CQ CO OO O2 r. ft QJ 03 Hi 1 "^ co o) o o oo >q ca c-q UT OS t-* t-' CQ* O 1— 1 I— 1 rH ^ JO CO O 00 rH IO ® m ^ cs CQ os ^t* cq w 5 -^ eg O cc o co" co* iri o s 5 CQ CQ rH CQ OO 'ft 1 "3 O «ol Ol <& O t- OO 1 S o g cq g Tt* !>* 00* 00 00* CQ CQ rH CQ 00 'ft TJ -2 "^ os o oo 10 „ H) -* CD CQ IO O rH t. O C^ O 00 •^J* CQ C5 CQ CO* CO JQ w 3 CO CQ rH CQ rH 1 M 6 * ^ ol IO rH OO b- O •^ 5O cq co CQ CO* CQ CO* CO rH • bo « ° fl CO Cq CQ CQ rH -2 d T/ ^ CO rH CQ rH O § QJ GO oq cq o co o E eg O co ^i ^^ l>- CO 8 PM T-H CQ ^ -* 16 w to o rrj « '£> SO O «O O rH 03 O ^ iq t> t>; oq o C3 O g rH CS OO OS « § ^ -* 10 TfH IB ^ . a 0 l_l ® IO V- 00 -Jf O 1 _, 03 &1 CQ OS OO O IO CQ i-H rH CQ CQ "a "c 3* ^ rrt CO ffl 03 >j 'o Tfl O O IO O O "^ CQ ^ O O rH in OS rH CQ C] CQ rH rH r^ CO b- l>- Cq rH O £ o O C rH r-l «D t- O in CQ b- os TJ< FH 'ft S3 T^ ^t ^^ CO CO C c eo eo eo so _. 1 cq" co" cq" CQ" § "ft ^ >. ^ q rH rH rH rH "S g j9*g 9*8 Kg • I's |^ s^ !*g 0) J-H qj *rH ^ *r-t (]3 "r-i QJ ^j 1 "rt "rt "rt "rt g EH j, S J, .S 2 S j, S I IvilViitil^-tJ 03030303 CO» B3 1* 13 O3 rH CM 'ft's •H| 0 g o os' o CO t- »n 00 Q? » <» OS OS o J2 § M co' -* 1 -' 50 n ^ rH in t- ^ "ft ft • 73 1 0 PC? <^ B°f Od t-H O O CO O rH CD 00 CD •*' 00 1 TH 5 0 OS 00 'ft S 0 .S O CO CO* rH CM rH 00 4) rD e ^ 00 OS ^ *^ • ® fl .^ CM rH ^^ M ert O ?5 co' CM" 0 be PQ S CM CM rH • a bo • OS r& rH CM CO ca g ® rr S O CO t- I C CO 1-4 § 0 CO m j> t~ rH CO CM 06 Q_i MH 6 "^? . oo CO Q g co' t~ Tj5 M 5 1O rH c n-j on ,_ t QJ CO q^ 0 •* exj O **1 *o m — 00 O CO ^ 'ft £ &J rH W CM 1 P|! CO TH CO b— CM rH CO EH -^rt1 CM "3 .®J1 ftq O T-H •*•" O ^4 "3. ° fl w S H .^4 »-H rH CM co m CO rH ft cS •^ rH CM B O ,Q CO CO co g ». »\ w > i •Si 'S,^ 3 o co os c-j t- 2 I— t- t-' id 10 •*' 2 •* CO t- CO O5 ^ CO rH rH ^ 03 Inl OO Ci I— O CO O rH rH (M •* CO O 00 • X g§1 ^2 GO CO O O l>» O CO CD L— CO fr~ O r-H ft & i p (H "S ^ c? 0 O »>- CO i-H O O t~ CO TjH O5 CO O T5 q ,9 a§! « § OQ O CO IO CO O Ttl t~ t- CO 00 O t-H « "ft • ^ nj ® fl^q O O CO CM CO O 90 t- O3 t~ 5Q O «H 0 09 ^ § 00 CS 3 r- oq ^2 l^. •* CO CQ kO CM rH rH Cvl rH V "3 CS fe h ^ « 0) -j rO Tj< — 1 O CO TjH O i-H O5 O r-H CO O bfi cu S°i CO CM rH O rH CM rH rH CM rH a «3 q •tf ^2 £ a ^ fH C3 O « « 5 •* Ol CO CO b- CO rH rH rH PH o fc -^3 W S n^ CD CM 1- i-H CO O rH •* IO OS OO O 3 5 | n § rH CO (N CO •* CO rH rH rH 0 K - 5 &- l£ ' •- : Z- ; Q I-H > * " *1 J a< ® OD ^ ft 3 8 ,Q 0 CO b- CO CO 00 O OS rH O t~ in CM p-H 60 « •if •§s u .2 13 B G 0 o 11 12 13 Check 14 15 16 17 Check 23-24 25-26 27-28 29 30-31 32-33 34-35 37-38 36 Lime sulfur, commercial, with Paris green 53 39 72 95 89 87 87 85 89 4 25 4 11 22 18 30 1 13 84 72 73 97 91 84 75 78 91 Lime sulfur, commercial, alone Lime sulfur, commercial, with arsenate of lead No treatment Lime sulfur, self -boiled, 12—12—100, alone Lime sulfur, self -boiled, 16-16-100, alone Lime sulfur, self -boiled, 20-20-100, alone Lime sulfur, self-boiled, 16-16—100, with arsen- ate of lead No treatment . EFFECT ON FRUIT Scab. — The applications of commercial lime sulfur made on Plats 11, 12, and 13, reduced scab on an average by 37 percent as compared with the average in the check plats. Most of the scab on the sprayed plats was of so light a nature as would not readily be noticed, occur- ring largely in the form of an early attack of the disease which did not disfigure the apples at picking time. The disfiguring marks of scab were largely confined to the untreated apples. The spray was therefore much more effective than the figures in the table indicate. The self-boiled lime sulfur showed little value in preventing attacks of scab, the average scab infection for the self-boiled lime-sulfur plats being 87 percent, as compared with 92 percent, the average on the unsprayed trees. Codling Moth. — Both Paris green and arsenate of lead exercised a most satisfactory control of this insect in every case. There was an 122 BULLETIN No. 185 [February, average infestation of 4 percent on the plat sprayed with Paris green (Plat 11) and of 2.5 percent on the plats sprayed with arsenate of lead (Plats 13 and 17), compared with an average of 12 percent on the untreated trees. Codling moth was evidently rather strongly at- tracted to the trees sprayed with lime sulfur ; the fruit on these trees was more severely attacked by this insect than the fruit on the un- sprayed trees, a difference that held consistently for all the plats sprayed with lime sulfur alone (Plats 12, 14, 15, and 16), which showed an average codling-moth infestation of 24 percent, or double the average infestation of the unsprayed trees. Curculio. — The differences in curculio infestation between the treated plats were not consistent, but with the exception of Plat 14, all sprayed trees indicated some degree of control by the treatments, as compared with the untreated plats. Even Plat 1.4, sprayed with self -boiled lime sulfur (12-12-100) alone, showed 3 percent less curculio injury than the average of the check plats. The addition of arsenate of lead and of Paris green to lime sulfur did not aid noticeably in controlling curculio, the average infestation in the plats where the poisons were used being 78 percent, as compared with 80.5 percent for the plats sprayed with lime sulfur alone. Contrary to the experience in the control of codling moth, lime sulfur appeared to exercise a repellent effect on the curculio. Plats sprayed with lime sulfur alone (Plats 12, 14, 15, and 16) showed an average infestation of 80.5 percent, as compared to an average infes- tation on the unsprayed trees of 94 percent. Self -boiled lime sulfur proved to be an inefficient fungicide. Lime sulfur (commercial) showed considerable fungicidal value. EFFECT ON FOLIAGE The foliage was good thruout this group, but was perhaps slightly better in Plats 13 and 17, where arsenate of lead was added to the fungicide, than in the other plats in the series. There were no rus- seted apples in the plats in this group. COMPARATIVE EFFECTIVENESS OF SPRAYING ONCE BEFORE THE BLOOM AND SPRAYING ONCE AFTER THE BLOOM The treatments used in Group 3, together with the fruit data re- corded, are given in Table 25. EFFECT ON FRUIT Scab. — In 1909 the spray which followed the fall of the petals was more effective in controlling scab than the spray which preceded the bloom. Codling Moth. — As was to be expected, the spray which followed the fall of the petals was more efficient in reducing codling-moth in- 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 123 jury than the spray which preceded bloom. The noteworthy point in regard to this treatment was the effectiveness of the one application, only 3 percent of the apples in Plat 21 (sprayed after the fall of the petals) being injured by codling moth, as compared with 17 percent on the check plat. TABLE 25. — EFFECTS OF INDIVIDUAL APPLICATIONS BEFORE AND AFTER THE BLOOM, USING BORDEAUX IN COMBINATION WITH ARSENATE OF LEAD, IN THE EXPERIMENTS AT GRIGGSVILLE, 1909 Plat Trees Treatment Percentage of picked apples affected by 1 QO &c - s73 ~ o 1« O Curculio -fa • • m S 03 Check 20 21 41 44-45 46-47 No treatment 89 85 49 17 12 3 83 88 87 0 1 23 Sprayed before bloom Sprayed just after fall of petals Curculio. — Both applications were evidently too early to exercise any control over the curculio. Russet. — Practically no russeting resulted from the application preceding the bloom. As a result of the application following the fall of the petals, 23 percent of the apples were more or less russeted. EFFECT ON FOLIAGE Cankerworms appeared in the orchard just as the leaf buds were expanding, but were completely checked by the application preceding the bloom. COMPARATIVE EFFECTIVENESS OF BORDEAUX WITH AND WITHOUT ARSENICAL INSECTICIDES The treatments used in Group 4, together with the fruit data re- corded, are given in Table 26. EFFECT ON FRUIT Scab. — This disease was immensely reduced in all the sprayed plats, the average reduction of the infection amounting to 52 percent. Bordeaux alone appeared to exercise a better control of scab than the combined Bordeaux and arseriate of lead or the combined Bordeaux and Paris green, as may be seen by comparing Plat 25 with Plats 35, 36, and 37. This idiosyncracy, in the light of other results, must be attributed to seasonal conditions or experimental error. Codling Mofh. — The addition of poisons to the Bordeaux reduced the injury from codling moth to an average of 4 percent (Plats 35, 36, and 37), as compared with an injury of 20 percent on the check 124 BULLETIN No. 185 [February, TABLE 26. — EFFECT OF BORDEAUX WITH AND WITHOUT ARSENICAL INSECTICIDES, IN THE EXPERIMENTS AT GRIGOSVILLE, 1909 Plat Trees Treatment Percentage picked apples affected by a OQ "•< o 1* O Curculio 25 35 36 37 Check 61-62 83-84 85-86 87-88 89 Bordeaux alone 7 16 13 11 63 15 1 3 8 20 77 63 68 82 93 Bordeaux with arsenate of lead, 6 Ibs. to 100 srals. Bordeaux with arsenate of lead, 4 Ibs. to 100 srals. Bordeaux with Paris green, % lb. to 100 gals. No treatment . trees and 15 percent on trees sprayed with Bordeaux alone. Arsenate of lead proved more effective than Paris green, reducing the injury to an average of 2 percent (Plats 35 and 36) as compared with 8 percent on the trees sprayed with Paris green (Plat 37). Curculio. — As compared with the check, where the curculio infes- tation amounted to 93 percent, the injury in the plats where arsenate of lead was used was reduced to an average of 65 percent and in the plat where Paris green was used to 82 percent. There was less cur- culio damage even in the plat where Bordeaux was used alone than in the check plat. EFFECT ON FOLIAGE More foliage injury occurred in Plat 37, sprayed with Paris green, than in the plats sprayed with arsenate of lead. COMPARISON OF MISCELLANEOUS SPRAYS The treatments used in Group 5, together with the fruit data re- corded, are given in Table 27. EFFECT ON FRUIT Scab. — Homemade Bordeaux and Target brand Bordeaux were equally efficient in controlling scab. Bordeaux made with carefully slaked lime showed no superiority over Bordeaux made with care- lessly slaked lime in lessening injury from this disease. The addition of iron sulfate to Bordeaux, which was added only to improve the ad- hesive qualities of the spray, did not increase the fungicidal value of the mixture. All sprays exercised a large degree of control over scab. Codling Moth. — Arsenate of lead, used thruout the group, reduced the amount of codling-moth injury satisfactorily except in Plat 42, where iron sulfate was added to the spray. Infection in this plat, how- 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 125 TABLE 27. — EFFECTS OF MISCELLANEOUS PREPARATIONS, IN THE EXPERIMENTS AT GRIGGSVILLE, 1909 Plat Trees Treatment Percentage of picked apples affected by fi 2* ^H 0 -§a o Curculio 1 03 B 1 26 27 Check 29 30 40 42 Check 63-61 65-66 67 70-71 72-73 94-95 99-100 98 Homemade Bordeaux with arsenate of lead 10 9 53 11 8 26 32 51 2 3 12 3 1 2 8 19 57 49 78 72 64 84 89 99 52 42 3 59 44 50 26 1 Target brand quick Bordeaux with arsen- ate of lead No treatment Bordeaux made with carefully slaked lime with arsenate of lead Bordeaux made with carelessly slaked lime with arsenate of lead Bordeaux with arsenate of lead Bordeaux with iron sulfate with arsenate of lead No treatment . ever, as shown by the corresponding checks, was higher than in the other plats included in the group. It cannot be concluded, therefore, that iron sulfate lessened the efficiency of the arsenate of lead. 126 BULLETIN No. 185 SPRAYING EXPERIMENTS IN 1910 AT CENTRALIA, MARION COUNTY BY L. EAEL FOGLESONG OBJECTS The objects of the experiments at Centralia in 1910 were to study : (1) the efficiency of Bordeaux and lime sulfur as fungicides; (2) the efficiency of homemade, commercial, and self -boiled lime sulfur for late spring and summer sprays; (3) the effects of adding lime-sulfur sludge to the clear solution; (4) the effects of using various proportions of lime and sulfur in making the self -boiled product; and (5) the rela- tive values of acid, neutral, and mixed arsenates of lead. LOCATION AND DESCRIPTION OF ORCHARD It was planned to carry out experiments bearing on the above ques- tions in several orchards — one each in Pike, Calhoun, Cumberland, Clay, and Marion counties. A very severe freeze, however, occurred April 23 and 24, which killed all the apples in all the orchards under consideration except the one located at Neoga, in Cumberland county. As a result the experimental work was abandoned for the season at all points except the orchard at Neoga, and one at Centralia in Marion county, which was maintained in order to study the effects of the vari- ous sprays on the foliage. The experimental plats at Centralia were located in the orchard of G. H. Perrine and Sons. The trees used were of the Ben Davis vari- ety, twenty-five years old. TREATMENT The trees were sprayed as follows : Plat Appli- cation Date Time Treatment 1 1 March 31 Just before bloom Commercial lime sulfur 2 April 11 Just after fall of petals diluted 1 to 30 with ar- 3 April 20 senate of lead, 4-100 4 May 31 2 1 March 31 Just before bloom Bordeaux,- 8-8-100, with 2 April 13 Just after fall of petals arsenate of lead, 4-100, 3 April 20 followed immediately 4 April 25 A maintenance coat of milk of with milk of lime, 8-100, lime this subsequent coat be- 5 May 16 A maintenance coat of milk of ing maintained lime 6 May 31 Just before bloom 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 127 Plat Appli- cation Date Time Treatment 3 1 March 31 Just before bloom , Bordeaux, 8-8-100, with 2 April 13 Just after fall of petals arsenate of lead, 4-100 3 April 20 4 May 31 4a 1 March 31 Just before bloom Homemade lime sulfur,1 2 April 12 Just after fall of petals without sludge, with ar- 3 April 20 senate of lead, 4-100 4 June 1 4b 1 April 1 Just before bloom Homemade lime sulfur,1 2 April 13 Just after fall of petals with sludge added, with 3 April 20 arsenate of lead, 4-100 4 June 1 5 1 April 2 Just before bloom Self -boiled lime sulfur, 2 April 14 Just after fall of petals 32-32-200, with arsen- 3 April 22 ate of lead, 4-100 4 May 30 6 1 April 2 Just before bloom Self-boiled lime sulfur, 2 April 14 Just after fall of petals 16-16-100, with arsenate 3 April 22 of lead, 4-100 4 May 30 7 1 April 2 Just before bloom Self-boiled lime sulfur, 2 April 14 Just after fall of petals 10-10-50, with arsenate 3 April 27 of lead, 4-100 4 May 30 8 1 April 2 Just before bloom Self-boiled lime sulfur, 2 April 14 Just after fall of petals 8-8-50, with arsenate of 3 April 27 lead, 4-100 4 May 30 9 1 April 2 Just before bloom Self-boiled lime sulfur, 2 April 14 Just after fall of petals 6-6-100, with arsenate 3 April 27 of lead, 4-50 4 May 30 11 1 April 2 Just before bloom Commercial lime sulfur 2 April 13 Just after fall of petals diluted 1 to 30 with ar- 3 April 28 senate of lead (acid),1 4 June 1 4-100 12 1 April 1 Just before bloom Commercial lime sulfur 2 April 13 Just after fall of petals diluted 1 to 30 with ar- ? April 28 senate of lead (nor- 4 June 1 mal),8 4-100 13 1 April 1 Just before bloom Commercial lime sulfur 2 April 13 Just after fall of petals diluted 1 to 30 without 3 April 28 arsenate of lead 4 June 1 1Prepared according to the formula recommended by J. P. Stewart, Penn. State Col. Agr. Exp. Sta. Bui. 92; 100 pounds sulfur, 50 pounds lime, 50 gallons water. 2Hemingway arsenate of lead. 'Sherwin-Williams arsenate of lead. 128 BULLETIN No. 185 [February, EFFECTS OF BORDEAUX AND LIME SULFUR In Plat 1, commercial lime sulfur controlled apple scab well. No spray injury was observed until several weeks after the fourth appli- cation, when a very small amount became noticeable. The leaves on the trees in this plat were perceptibly smaller than those from trees treated with a spray containing a surplus quantity of lime, as were the leaves from trees sprayed with homemade lime sulfur (Plat 4), but they had excellent color, and the fruit buds formed during the season were very large and numerous. Standard Bordeaux (8-8-100) applied to the trees in Plat 3 pro- duced severe spray injury, but not until after the third application, when many leaves turned yellow and fell to the ground. The fruit buds on this plat were perceptibly smaller than those on Plats 1, 4, and 5, probably because of the severity of the injury to the foliage. Scab was controlled by the standard Bordeaux both in this plat and in Plat 2. EFFECTS OF HOMEMADE, COMMERCIAL, AND SELF-BOILED LIME SULFUR The homemade mixture of lime sulfur did not control the scab so well as the commercial, used on Plat 1. Altho the damage was small, homemade lime sulfur resulted in more foliage injury than commercial lime sulfur, and this injury came earlier in the season. The foliage, however, was very good, and the fruit buds were apparently as large and as numerous as in Plat 1. Plat 5, where the trees were sprayed with self -boiled lime sulfur, showed very little benefit from the spray. Scab was present in almost as large quantities as on the untreated foliage of the check trees. The leaves on the trees sprayed with self-boiled lime sulfur appared to be larger than those on the other trees sprayed with lime sulfur. This spray made the tree and foliage very white, and the material stuck well. Its fungicidal value, however, proved small. EFFECTS OF ADDING LIME-SULFUR SLUDGE TO A CLEAR SOLUTION OF LIME SULFUR In Plat 4 one-half the trees were sprayed with homemade lime sul- fur with the sludge included, and the other half without the sludge. The lime sulfur was made by G. H. Perrine and Sons at the beginning of the season and kept as a stock solution. The specific gravity of the material was determined by hydrometer test and the spray used at a dilution corresponding to the strength of the commercial material. The trees which were sprayed with the homemade mixture combined with the sludge, Plat 4b, were more plainly marked by the spray, but no difference in the vigor or color of the foliage could be detected, 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 129 either favorable or unfavorable, as a result of the presence of the sludge in the mixture. EFFECTS OF SELF-BOILED LIME SULFUR MADE IN VARYING PROPORTIONS All combinations gave very similar results as far as could be de- termined from the foliage. The amounts of scab and insect injury on the foliage in each of the plats were very similar, as were also the vigor and color of the leaves. Compared with untreated trees and with trees sprayed with Bordeaux and ordinary lime sulfur, these plats demon- strated the inefficiency of self -boiled lime sulfur as a fungicide for apple foliage. EFFECTS OF ACID, NEUTRAL, AND MIXED ARSENATES OF LEAD As the principal purpose of arsenate of lead is the control of in- sects affecting the fruit, the results of these tests in 1910 are of com- paratively little value. All brands of arsenate of lead gave equally good control of insects affecting the foliage. Arsenate of lead com- bined with lime sulfur increased the fungicidal value of the mixture over lime sulfur alone, as indicated by the control of scab. Slight spray injury occurred in all the plats in this group but no differences in amounts or character could be observed. 130 BULLETIN No. 185 [February, SPRAYING EXPERIMENTS IN 1911 AT CENTRALIA, MARION COUNTY BY L. EARL FOGLESONG OBJECTS The objects of the experiments at the Centralia orchard in 1911 were: (1) to test the efficiency of Bordeaux and lime sulfur as fungi- cides for the apple; (2) to determine whether or not applications of lime sulfur made while the trees are dormant have any value in con- trolling scab and other diseases during the succeeding growing season ; (3) to compare the efficiency of light and heavy applications of Bor- deaux and lime sulfur ; (4) to learn the effects of adding copper sul- f ate to lime sulfur in order to increase the f ungicidal value of the mix- ture ; and (5) to determine the effects of maintaining a Bordeaux coat- ing on the fruit and foliage by sealing it in with a second coating of Bordeaux or with a coating of milk of lime, the coating to be renewed with sufficient frequency during the season to protect the first applica- tion from the action of rain and air. LOCATION AND DESCRIPTION OF ORCHARD The plats under treatment were located in the same orchard and in the same block of trees as those of the experiments in 1910. OUTLINE OF TREATMENTS Sixteen plats arranged as shown in Chart 7 were sprayed as fol- lows: Plat Appli- cation Date Time Treatment A 1 April 15 Just before bloom Bordeaux arsenate of lead 2 May 2 Just after fall of petals Lime sulfur arsenate of lead 3 May 16 Lime sulfur arsenate of lead 4 June 26 Lime sulfur arsenate of lead B 1 April 15 Just before bloom Bordeaux arsenate of lead 2 May 4 Just after fall of petals Bordeaux arsenate of lead 3 May 16 Lime sulfur arsenate of lead 4 June 29 Lime sulfur arsenate of lead G 1 April 15 Just before bloom Lime sulfur arsenate of lead 2 May 4 Just after fall of petals Bordeaux arseuate of lead 3 May 15 Bordeaux arsenate of lead 4 June 27 Bordeaux Hrsenate of lead D 1 April 15 Just before bloom Lime sulfur arsenate of lead 2 ; May 2 Just after fall of petals Lime sulfur arsenate of lead 3 ,May 15 Bordeaux arsenate of lead 4 June 27 Bordeaux arsenate of lead 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 131 Plat Appli- cation Date Time Treatment E 1 April 15 'Just before bloom Lime sulfur arsenate of lead 2 May 2 Just after fall of petals Lime sulfur arsenate of lead 3 May 16 Lime sulfur arsenate of lead 4 June 29 Lime sulfur arsenate of lead P 1 April 15 Just before bloom Lime sulfur arsenate of lead, 2 May 3 Just after fall of petals 4 applications. This plat re- 3 May 16 ceived no winter applica- 4 June 29 tion of lime sulfur G 1 April 15 Just before bloom Bordeaux arsenate of lead, 4 2 May 4 Just after fall of petals applications. This plat had 3 May 15 received no winter applica1 4 June 26 tion of lime sulfur H 1 April 15 Just before bloom Bordeaux arsenate of lead, 4 2 May 4 Just after fall of petals applications. This material 3 May 15 was applied in large quan- 4 June 27 tities I 1 April 15 Just before bloom Bordeaux arsenate of lead, 4 2 May 4 Just after fall of petals applications. This material 3 May 15 was applied in quantities 4 June 29 even less than for the ordi- nary spraying J 1 April 15 Just before bloom Bordeaux arsenate of lead, 4 2 May 4 Just after fall of petals regular applications. Extra 3 May 15 applications were for main- 4 June 6 An extra application taining the coating of Bor- 5 June 28 deaux and were made of tho 6 July 21 An extra application same material 7 Aug. 12 An extra application K 1 April 15 Just before bloom Bordeaux arsenate of lead, 4 2 May 4 Just after fall of petals regular applications. Extra 3 May 15 applications were for main- 4 June 6 An extra application taining the coating of Bor- 5 June 29 deaux and were made with 6 July 21 An extra application milk of lime, 8-100 7 Aug. 12 An extra application L 1 April 15 Just before bloom Bordeaux alone, 8-8-100 2 May 2 Just after fall of petals Arsenate of lead, 4-100 3 May 16 Arsenate of lead, 4-100 4 June 28 Arsenate of lead, 4-100 M 1 April 15 Just before bloom Lime sulfur alone, 1—17 2 May 2 Just after fall of petals Arsenate of lead, 4-100 3 May 16 Arsenate of lead, 4-100 4 June 28 Arsenate of lead, 4-100 N 1 April 15 Just before bloom Lime sulfur, 1-17, with cop 2 May 2 Just after fall of petals per sulfate, 4-100 3 May 16 4 June 29 132 BULLETIN No. 185 [February, Plat Appli- cation Date Time Treatment O 1 'April 15 Just before bloom Lime sulfur, 1-17, with cop- 2 May 2 Just after fall of petals per sulfate, 8-100 3 May 16 4 June 29 P 1 April 15 Just before bloom Lime sulfur, 1-17, with cop- 2 May 2 Just after fall of petals per sulfate, 12-100 3 May 16 4 June 29 O O O O O o O o oo Winesap (Q)B*n DavU. (&) Ben Daris Check QRestt. CHART 7. — PLAN OF PLATS IN ORCHARD OF G. H. PERRINE AND SONS, CENTRALIA, 1911 APPARATUS AND PREPARATION OF MATERIALS A gasoline power spray outfit equipped with spray tower belonging to G. H. Perrine and Sons was used to make all the applications. The spray was applied at a pressure of approximately 150 pounds to the square inch. The lime sulfur used thruout these experiments was made by G. H. Perrine and Sons in a newly installed steam cooker. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 133 It was made according to the Illinois formula: 50 pounds lime, 100 pounds sulfur, and 66 gallons water. While the trees were dormant, the spray was applied at a dilution of 1 gallon of lime sulfur to 7 gal- lons of water. During the summer it was applied at a dilution of 1 gallon to 17 of water. Bordeaux was made on the standard formula : 8 pounds lime, 8 pounds copper sulfate, and 100 gallons water. Arsen- ate of lead at the rate of 4 pounds to each 100 gallons of spray mix- ture was used at all applications unless otherwise noted. CHARACTER OF RECORDS AND METHOD OP MAKING A record of daily temperatures, rainfall, cloudiness, and wind was made. Notes were taken from time to time on the amount, vigor, and color of the foliage. All dropped apples were examined to determine the effects of the sprays in preventing injury from insects and fungi. At the close of the season the apples were picked, and four representa- tive trees were selected from each plat and from each check row for record making. Fifty apples chosen at random from the crop of each tree were taken from the sorting table and examined for evidences of scab, sooty blotch, flyspeck, bitter rot, blotch, and other fungous dis- eases, and for injuries from codling moth, curculio, and other insects. The data obtained thruout the season were later tabulated for detailed study. WEATHER CONDITIONS The weather, tho significant in this year 's data, did not cause much trouble at or during the spraying periods. The times of spraying Plats J and K were dependent on the occurrence of rains. A cold rain which continued from April 27 to April 29 fell during the blossoming period and prevented the pollination of the large set of blossoms. The crop was, therefore, light, and because of this fact the records obtained from the fruit were less conclusive than was desired. EFFECT ON FOLIAGE In the general study of the foliage, spray injury was particularly noted. More or less injury was caused by all the sprays, altho the time of application was an important factor in this connection. The lime sulfur used at the third application was unusually harm- ful this year, — more so than in any year since the writer has closely observed its action. Oversprayed branches were the most severely burned. The injury to the foliage, however, was soon effaced as far as the eye could discern. Badly burned leaves fell and the remaining Leaves were rich in color and apparent vigor. Bordeaux injured the foliage and russeted the fruit. The apples russeted by the lime-sulfur spray looked, and really were much less in- jured in the fall than in midsummer, the injury thinning out and be- coming inconspicuous ; but the Bordeaux-sprayed apples were in many 134 BULLETIN No. 185 [February, instances so severely injured as to be unmarketable. More foliage was lost from the Bordeaux-sprayed trees than from those sprayed with lime sulfur, and the general appearance thruout the summer was poorer. The foliage of Plats J and K (sprayed with Bordeaux) was much poorer than that of the plats sprayed a fewer number of times with the same mixture. The repetition of the spray was detrimental under the conditions of this year. In percentage of injury and general ap- pearance, these two plats varied but little. The foliage on Plats L and M (sprayed with Bordeaux arsenate of lead, and lime sulfur arsenate of lead, respectively) was good average foliage at the close of the season. The amount of injury present was much less than that produced by Bordeaux alone, and slightly less than that produced by lime sulfur alone. There were sev- eral severe attacks of yellow-leaf on these plats when no other plat was so infested. The appearance of the foliage in Plats N, 0, and P was generally below the average of the other plats. The sprays resulted in consid- erable foliage and fruit injury and there was a dark discoloration on the bark, foliage, and fruit, due to the copper and sulfur compound, that was unsightly to one accustomed to the light appearance caused by other sprays. A good deal of injury was caused this year by all sprays, which in order of severity ranked as lollows : Bordeaux, copper sulf ate and lime sulfur, lime sulfur, and arsenate of lead. EFFECT ON FRUIT The fruit from these plats was picked and examined in October, with the results presented in Tables 28 and 29. Scab. — Bordeaux, lime sulfur, and the combination of lime sulfur and copper sulfate all reduced the amount of scab to a very marked degree as compared with the check plats. Even Plat M, which showed the poorest control of any sprayed plat, gave only 12 percent of scabby apples, as compared with 44 percent for the unsprayed trees. Plats A, B, Gr, H, J, K, and L, all of which received Bordeaux for the first application, showed an average of only 3 percent of scabby apples, whereas those plats receiving lime sulfur at the first application aver- aged 5.5 percent. The difference, tho small, rather consistently fa- vored Bordeaux for the first spray. In the present season, the spray applied before the blossoms opened was clearly the important one in the control of scab. Where no fungicide was used after the blossoms fell, as in Plats L and M, the control of this disease was good. The re- sults for these two plats favored Bordeaux as a first application more strongly than the general results for the whole series of treatments; Plat L, which received Bordeaux, showed only 7 percent of scab, as FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 135 ning snouag os oo ec o eo co o o co Tj(ooiooa«0 q;oui OO O O b-CO r-f' OJCO IO (MCO CO CO COCO CO COCOCOb-CO i O id 1 <» :— 00 K «3 CO OO to T|< ' CT fOOO O g 9 SS83" C3 CO 3J Bnouag O CO Oi «OOO to OO O rH rH rH CO CO CO OS .cot>. cc cocococo® * : «Ha> g cc pqfq pq pq pq o Q o 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 137 contrasted with Plat M, which received lime sulfur and showed 1 2 per- cent of scab. It will be observed that the treatment in both plats left sufficient infection to cause serious damage in a season favor- able for the development of scab. There is no evidence to show that the dormant-tree application exerted any influence in checking it. Blotch. — Bordeaux, when used for the second and third spray- ings, gave better results in the control of blotch than lime sul- fur, as may be seen by comparing Plats C, Gr, H, J, and K, all of which received Bordeaux for the second and third applications, with Plats A and F, which received lime sulfur for the same two ap- plications. Plat E, sprayed with lime sulfur thruout the season, showed only 6 percent of blotch, a control almost as good as the aver- age plat where Bordeaux was used in one or more of the final spray- ings, but not so good as where Bordeaux was used exclusively, as in Plats H, J, and L. Arsenate of lead alone was quite ineffective as a fungicide for blotch, Plats L and M, which received only arsenate of lead at the two final sprayings, showing more blotch than even the untreated plats. Lime sulfur with copper sulfate reduced blotch no- ticeably, but was no more effective than lime sulfur alone, and was considerably less effective than Bordeaux. Sooty Blotch. — Sooty blotch was better controlled by Bordeaux, when used for the third or fourth application, than by lime sulfur. The addition of the larger quantities of copper sulfate to lime also resulted in a marked reduction in the amount of sooty blotch. Arsen- ate of lead, however, proved ineffective as a fungicide for this disease. Decay. — Black rot was common on all the check plats. Except in the plats sprayed with arsenate of lead at the second and third appli- cations, and in Plat N, where two pounds of copper sulfate were added to the regular dilution of lime sulfur, there was a lessening of the dis- ease as a result of all the sprays. In this respect Bordeaux and lime sulfur proved about equally effective. Codling Moth. — The infestation of codling moth in the various plats could hardly have been uniform, since Plats B and D, which were properly sprayed with arsenate of lead in combination with Bordeaux or lime sulfur, showed considerably more infection than the composite check plat, while Plats A and C, which were similarly sprayed, showed nearly as much. The infestation in the several check plats was also very uneven. Comparing treated plats with their adjoining checks, a fair degree of control is found. Comparing the average injury from codling moth on all sprayed plats, except B and D, with the composite check, it is found that the sprayed plats showed an average percentage of 4.2 injured apples and the check plats an average percentage of 12. Curculio. — The results indicated a somewhat uneven distribution of infestation by the curculio. On the average, the sprayed plats showed less injury than the checks, and Plats A, C, J, K, and P showed 138 BULLETIN No. 185 [February, decidedly fewer injured apples than the unsprayed plats. On the other hand the other sprayed plats showed so little difference from the checks that definite conclusions cannot be based on the results. Russet. — Bordeaux and the combination of lime sulfur and copper sulf ate were responsible for more russeting of the fruit than lime sul- fur or arsenate of lead. Where Bordeaux or the combination of lime sulfur and copper sulf ate were used for all applications (Plats G, H, J, K, N, 0, and P), more than 85 percent of all the apples were more or less russeted. Plats E and F, sprayed thruout the season with lime sulfur, showed only 66 percent of russeted apples, and the russet on this fruit was trivial in character compared with that on the apples of the other plats, only iy2 percent being severely russeted. Burn. — This is an arbitrary term which was immediately and sug- gestively applied to an injury found on the trees sprayed with lime sulfur this summer. It was found most often on the south and west sides of the trees, and might have been called a sun scald but for the fact that it was found only on lime-sulfur sprayed trees. The burn followed both the third and fourth applications. SUMMARY OF RESULTS AT CENTRALIA, 1911 1. The season's work confirms the already well-established effec- tiveness of Bordeaux as a fungicide for the control of scab, blotch, sooty blotch, and black rot. It indicates also that lime sulfur pos- sesses only slightly less efficient fungicidal properties, at least in a dry season, than Bordeaux. Both fungicides caused some injury to the fruit, Bordeaux in the form of russet and lime sulfur in the form of burn. Bordeaux was more injurious to the foliage, causing some yel- low-leaf and much spotting. On the whole, honors for the two sprays were even. 2. Applications of lime sulfur made while the trees were dormant failed to exercise any controlling effect over apple scab or blotch dur- ing the ensuing season. 3. No results were obtained bearing on the comparative effects of heavy and light applications of Bordeaux and lime sulfur. 4. The addition of copper sulfate to lime sulfur proved unnec- essary and inadvisable, owing to the severe injury which it caused to foliage and fruit. 5. Double applications of Bordeaux and coatings of milk of lime were not more satisfactory than single applications of Bordeaux in the control of scab. Double applications of Bordeaux were more injurious to the foliage and caused more russeting of the fruit than single ap- plications. 6. Arsenate of lead alone showed no noticeable fungicidal prop- erties. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 139 SPRAYING EXPERIMENTS IN 1912 AT ANNA, UNION COUNTY BY L. EAEL FOGLESONG OBJECTS In formulating this year's spray schedule the following questions were considered and groups of treatments were arranged with a view toward their solution: (1) the relative efficiency of Bordeaux and lime sulfur; (2) the relative efficiencies of various dilutions of lime sulfur; (3) the relative efficiencies of moderate and heavy applications of Bordeaux; (4) the relative efficiencies of various classes of arsenate of lead ; (5) the fungicidal value of various arsenates of lead when added to lime sulfur; (6) the possibility of interchanging lime sulfur for Bordeaux, or vice versa; (7) the best time and number of times for spray applications; and (8) the value of copper ferrocyanide, both as a fungicide and as an insecticide. LOCATION AND DESCRIPTION OF ORCHARD The orchard used for these experiments is located in Union county, three miles southwest of Anna, in the unglaciated portion of southern Illinois. This orchard, which is owned by Mr. F. P. Anderson, of Anna, has been well sprayed, pruned, and cultivated. There are a large number of varieties of apples on the farm, but the experiments were made only on Jonathan and Winesap. With but few exceptions the treatment was the same for each variety. TREATMENT The experimental areas were divided into plats, each of which was treated in the manner described in the various tables which are pre- sented in connection with the results which were obtained. The arrangement of these plats is shown in Charts 8 and 9. APPARATUS AND PREPARATION OP MATERIALS Unless otherwise stated, the Bordeaux used in these treatments was made on the formula, 8 pounds copper sulfate, 8 pounds lime, and 100 gallons water. The lime sulfur was a commercial brand testing between 32.5° and 33° Baume, or 1.2889 and 1.2946 specific gravity, and was used at the rate of 3 gallons in 100 gallons of the diluted mixture (approximately 8 pounds sulfur in 100 gallons) ; arsenate of lead in the paste form was added to the diluted spray mix- ture at the rate of 4 pounds per 100 gallons. The copper ferrocyanide 140 BULLETIN No. 185 [February, Oo ooo ooOO ooOO Jonathans Resets . Davis CHART 8. — PLAN OF PLATS IN JONATHAN BLOCK IN ORCHARD OF MR. F. P. ANDERSON, ANNA, 1912 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 141 QOO ©©©©©©© ©®©©©®©©©O oooooooo O o (o) Wlaesap Resets Y. Transparent CHART 9. — PLAN OF PLATS IN WINESAP BLOCK IN ORCHARD OF MR. F. P. ANDERSON, ANNA, 1912 142 BULLETIN No. 185 [February, was made on the formula, 2 pounds potassium ferroeyanide, 2 pounds copper sulfate, and 100 gallons water. The two substances were mixed at equal and full dilutions. Each plat was sprayed three times after the dormant-tree spray; Application 1 was made when the blossoms were in the cluster-bud stage; Application 2 was made immediately after the fall of the petals ; and Application 3 was made about 10 days after Application 2. The Jonathan block was sprayed with winter- strength lime sulfur (1 to 10) April 6; the Winesap block received a similar spraying, April 10, at a strength of 1 to 12, the weaker dilution being used because the buds were farther advanced at that time. Two additional summer applications were made to certain plats in the Winesap block. All applications were made with a gasoline power outfit equipped with a tower, to permit spraying the entire tree. The spray was applied at a pressure of 200 pounds per square inch, using Vermorel nozzles for the first application, Bordeaux nozzles for the second application, and Friend nozzles for all succeeding applications. CHARACTER OF RECORDS AND METHOD OP MAKING Foliage. — Notes were made during the early part cf the season at weekly intervals, and during the latter part of the season at bi-weekly intervals, on the vigor, color, and amount of foliage. Comparisons were thus obtained of the effectiveness of the various spray mixtures used in controlling the insect pests and fungous diseases which attack the foliage of the apple. Direct effects of the spray mixtures them- selves upon the foliage were also observed. They were in the form of injuries to the leaves, and included a brown spotting and the yellow- ing of part of the foliage as a result of certain applications. Altho these effects alone were not sufficient to base conclusions upon, they were, nevertheless, important in the compilation and study of results from the spraying treatments. Fruit. — Two hundred of the dropped apples from each tree were examined to secure records of their injuries. Where the number of "dropped apples" was less than 200, all the fallen fruit was exam- ined. The records on the picked fruit were made in the following manner: The apples from all of the trees except those discarded be- cause of deviation from the standard type within the block, diseased and undersized trees, trees which failed to bloom, trees of odd vari- eties, or trees which for other reasons were not typical of those within the plat, were counted, graded, and weighed. The samples examined, which included 200 apples each, were collected at random from the whole crop produced by each tree, in the same manner and under the direction of the same man, in an attempt to secure a uniform com- parison thruout the plats. A workman chosen for his reliability and good sense picked from each tree the required number of apples. His 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 143 ladder was placed at least four times for each tree, once in each quar- ter of the tree. The apples were picked without regard to size, blem- ishes, or other quality, in order to secure samples that fairly repre- sented the crop. WEATHER CONDITIONS The weather at the time of the dormant spraying was cloudy, and a very light rain followed the application made to the Jonathan block. At the time of the first summer spraying (the cluster-bud spraying) the weather was windy and cloudy with more or less rain. Plats 1 and 2 had to be resprayed, as it was believed that more or less spray material was washed off by rains which occurred soon after its appli- cation. At the time of the second application the weather was again cloudy, but no rainfall occurred to prevent the completion of the reg- ularly scheduled work. Ideal weather prevailed at the time of the third application ; there was a bright sun, very little wind, and no rainfall. Rain interfered with both the later summer applications ; it was necessary, however, to make them as nearly at the correct time as could be done under the circumstances, respraying the plats where the spray appeared to be washed off by rains which followed the oper- ation. The latter part of the summer was dry. EFFECT ON FOLIAGE FOR ALL TREATMENTS The observations on the effects of the different sprays on the foliage are summarized as follows: Where lime sulfur alone, lime sulfur arsenate of lead, copper ferrocyanide alone, and copper ferrocyanide arsenate of lead were used for the first application, no spray injury resulted. Bordeaux arsenate of lead, at the time of the first applica- tion, appeared to cause a small amount of burning of the foliage, the injury being confined to the tips of the expanding leaves. In the case of the second application, some injury to the foliage resulted from the application of lime sulfur alone, and also from lime sulfur ar- senate of lead. None appeared to follow the application of Bordeaux arsenate of lead or copper ferrocyanide after the second application. The spray was applied without any immediate injury to the foliage from any of the spraying materials used. Two weeks, however, after the third application, the trees sprayed with Bordeaux began to show noticeable foliage injury, particularly in the Jonathan block. Two severe epidemics of yellow-leaf occurred on the trees where Bordeaux was used. Each outbreak followed a period of rainy or cloudy weather in the Jonathan. It is estimated that 25 percent of all the Bordeaux- sprayed foliage in the Jonathan block turned yellow and fell to the ground in the course of these two epidemics. The attacks of yellow- leaf, were, however, much more severe in the Jonathan block than in the Winesap block. Injury began to appear on the leaves of the trees 144 BULLETIN No. 185 [February, ijassni BJ8A3g s°°s° q^p i* 00 t- W «5 CQ i-l CO 00 CD 'gl "o 0 o> 0 W •2 s R .8* epTS t- TP CO W t- » ^* 05 CO _ vi 0> _ r^J ® ^ ^5 « MB MB o .9 o o .5 pq^pq^ N H-iti-i 0-43 °PTS qeog qnog pg pg OOOOr-IOOOOaOMOiMOiHO 4> e8 ^> O tH1— 'tH O q_, O » ~ v^ ~ "-^ ~ . o . o . o . o . o . o . o . o - o o r-li-l^ 1916} FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 147 H a f3 M w I §M O HH « H 9 W !zi H CO HH K «s gw PH &; 2 >O 00 T}< C5 00 i-l •^ W Od CO JO CO CO OS b- «H "« « ° jg w> OPTS ^^ 55 Oi 10 ^o ^^ CQ i— i i^ eg eg eg 00 •<** CO || 1 x^° i— i i— i i— i eg 2 rt WSoS r-f b- co q«S co ^ co eg co CQ r-i co b- co «|,£ otimuno O O ^f tO t£> O eg eg r-i IH i-i eg o co o eg eg co f|| So0 eg i-t co 10 t~ MS •^ og eg co co eg O 00 b- co co •* f-< &•?£ so ^* co eg co co CO «D 0 CO „ A*Blds pg «M 5 * 5 £ ££ * ££ 0." 03 o3 jfBldg pg HJ .rH -*K3 -« vSD **9 N>« v» ^^ «| A»*W ^^ 5 5 5 5 •: ir a 6 •Ci cS ID . n$ 173 • ^ • ^ * * ^ * • ci CM *ctf • ci • • rj rt cd n cd o3 cd • T3 T3 ^j «M «M H OJOirtS^rt^a^^rt qj "cj cS ^ QJ Q^ Q^ ^ oRno,nD 00 r-( t~ (M rH CO !£ 0 rt N ^ <0 CO^.0 1 B l| g 33$ ll s be ePTS O *H CQ ^ i— ! CO i— f I-H 3 B || bo ePTS B N 00g t^ 10 oi t^ oo oo o (0 g cu W$og co qt?og •* (M TJH OJ - 1~ FH — CI qisog r-l 1>- -H 1C O5 1C CO ^ CO ^^ CO CO ^ Ir^ S § qBOg co co o iH CO *UdB tflS ^ ^ ^ -^ ^ to H 1-1 § /Bids pg JJ M o.2 CD AB.. ,Is W ^ ^ 5 ^ s ^ § Hcq Q rH || /Bids pg #S «H S 39 "-/" Ctf A'uids pg ^ ^ 5 g ^ ^ OiH PQ 03 A*i:.iJs ^SJ 5i^ -Z • — S /Bids pg * S * S: * * Bj • 0 /Bids m ^ ^ * * * * | S I fc i 3 111111111111 M o "S g §3 >» T3 5 "a oooooooooooo E ^ H a -t-> 03 ° S 03 ililllillill I EH 03 03 B 030303030303030303030303 1 CO CO CO CO CO CO CO CO CO CO CO CO c?Tfc?c?c?'?c?Tfl?c?Tc? k O 02 "S C8 CQ TO ~t-" <2tS'S<2t2-l fj § OH 3 *A«Q CQ OS t- •* Oi > •-^ ptj'rj «! 03 d (S * OI8A8g co in m onno.no -<*i oq t^ t^ oq -^t oq eo "o S- 333$ wi epig t~ l-J Tt« CO Q SjftBO 00 00 00 •* r-l iH | t -EFFECTS • a g^- S£ § § £ i £ C3 •""5 ^-t Co eo § H illi 41 S o oq LO TC 2 -^g 153 ^eSLg eo toco o ^ K onno.no Ci co co t-^ €3 Qi O XA"[eO 1^5 t*» t^» Oi 1— I fe * *Tog i-i co fo o co qeog iH CO TJ( CO i-H rH iH OO 'M S ouno.no O CO l~- •* cq cq OQ co 111 So co cq •* • -* ro co CM co OJ >^ it i 3-° oq (M co co o EH O.1^ j< I 4 Llj Tt* 1— 1 CO »7 e-, ^a o XH Q °S 6 »C Tfl i-H rH rH rH rH w be cs C3 a "" 3 -M / -3 t~ OO (M W OS h S PH ^ AA[KkJ Cl rH o rH PH H £ rt qo^oiq rH CO OS rH O § ft 03 SnnpOQ oo -* co cq IO CM CNI CM xf EH "~ ' tS 03 O CS ~ qBDg 00 CD rf< LO CO 2 £ 2 "Jj O ^>^§ § CO H t> o cs §5 -^ O O ^ iC R U B C 3 fl H h tg ^2 JS « ^ E T t^ ^H CQ CS O 03 03 :_ — i. o o o -5 o o -* O O M PQ ^ • rM g Is rH CO •* rH 03 5 H 1 £ CO rH C<1 ^ 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 155 deaux arsenate of lead and lime sulfur arsenate of lead were included in these tables for comparison. The results were as follows : Scab. — Copper-ferrocyanide sprays were less efficient in prevent- ing injury from scab than Bordeaux and lime-sulfur sprays. The ad- dition of arsenate of lead to copper ferrocyanide appeared to increase the fungicidal value of the spray. In the Winesap block the trees sprayed with copper ferrocyanide alone were as severely attacked by scab as the unsprayed trees. Sooty Blotch. — As in the case of scab, the copper-ferrocyanide sprays proved less efficient in the control of sooty blotch than either Bordeaux or lime sulfur. The addition of arsenate of lead, however, to copper ferrocyanide considerably increased the fungicidal value of the spray. Codling Moth. — In both the Jonathan and Winesap blocks the cop- per-ferrocyanide sprays were not effective in controlling this insect. The addition of arsenate of lead to the spray reduced the damage from codling moth appreciably, especially in the Jonathan block. Russet. — There was a noticeable amount of russet on the plats sprayed with copper ferrocyanide and arsenate of lead in the Jona- than block. The russet was less severe than on the apples which had been sprayed with Bordeaux, but was much more severe than on the apples sprayed with lime sulfur. Copper ferrocyanide caused less injury in the form of russet on the Winesap apples than on the Jona- thans. The addition of arsenate of lead to copper ferrocyanide in- creased the amount of russeting on the Jonathan apples. 156 BULLETIN No. 185 [February, SPRAYING EXPERIMENTS IN 1911 AT GRIGGSVILLE, PIKE COUNTY BY ALFEED J. GUNDEBSON, FIRST ASSISTANT IN POMOLOGY OBJECTS In the spraying work at the Griggsville station during 1911, ex- periments were conducted to determine the following points: (1) the relative value of lime sulfur and Bordeaux as summer sprays; (2) the value of winter applications of lime sulfur; (3) the relative effect of light and heavy applications of Bordeaux; (4) the means of reducing injury following the use of Bordeaux; (5) the value of interchanging lime sulfur and Bordeaux as summer sprays ; (6) the value of arsenate of lead as a fungicide when used alone for controlling codling moth ; and (7) the value of spray made by adding copper sulfate to lime sulfur. LOCATION AND DESCRIPTION OF ORCHARD The orchard used for these experiments belonged to Mr. G. War- ton and was located one mile south of Griggsville. About one hundred and sixty fifteen-year-old trees were used, which, with the exception of a few trees of odd varieties, consisted of Ben Davis. They were planted about thirty feet apart each way. The general vigor of the trees was good, considering that they had never received any care. No spraying had been done in the orchard ; consequently it had never produced a profitable crop. The orchard offered ideal conditions for carrying on the experiment. OUTLINE OP TREATMENTS In laying out these experiments, the orchard was divided into six- teen plats of eight to eleven trees each, and a check or unsp rayed row was left thru the entire length of the orchard. These plats were grouped and sprayed as nearly under the same conditions as possible, especial care being taken that the plats in a given group should be strictly comparable. The plats in the orchard were sprayed as follows: Plat Appli- cation Date Treatment A 1 2 3 April 20 May 9 May 22 Heavy spraying with lime sulfur arsenate of lead » )> » » » )) » )> B 1 2 3 April 20 May 9 May 22 Heavy spraying with lime sulfur arsenate of lead jj } > > } ) } » } > r ) ) > 1916] 157 Plat Appli- cation Dat e Treatment G 1 2 3 April May May 20 9 22 Heavy spraying with Bordeaux arsenate of lead » > > n }} a n n n a > } n n nn D 1 2 3 April May May 20 9 22 Heavy spraying with Bordeaux arsenate of lead a t t a ) > it lilt E 1 2 3 April May May 20 9 22 Light spraying with Bordeaux arsenate of lead it it tt a a 1 1 1 1 n 1 1 . tt tt tt tttt P 1 2 3 4 5 6 April May May June June July 20 10 23 1 12 25 Heavy spraying with Bordeaux arseuate of lead t t t t t t tt tt tt t t t t t t tt tt tt tttt tt t t tt tt it tttt tt tt t t t t tt tttt tt tt t t tt tt tttt G 1 2 3 4 5 6 April May May June June July 20 10 23 1 12 25 Heavy spraying with Bordeaux arsenate of lead it i it it It tiii a i t i a .it an it t a 1 1 1 1 tin it t it tt it tttt Each application was followed by a 4-50 solution of lime. H 1 2 3 April May May 21 11 23 Heavy spraying with Bordeaux arsenate of lead " lime sulfur " a tt 1 1 a tt tt an I 1 2 April May 21 11 Heavy spraying with Bordeaux arsenate of lead 3 May J 1 2 3 April May May 21 11 23 Heavy spraying with lime sulfur arsenate of lead " " " Bordeaux " tt it a it it an K 1 2 3 April May May 21 23 Heavy spraying with lime sulfur arsenate of lead " " " Bordeaux " " " L 1 2 3 April May May 21, 10 24 Heavy spraying with Bordeaux arsenate of lead " " arsenate of lead 1 1 a it a it M 1 2 3 April May May 21 10 24 Heavy spraying with lime sulfur arsenate of lead . ' arsenate of lead " " " arsenate of lead N 1 2 3 April May May 21 12 24 Heavy spraying with lime sulfur arsenate of lead plus 4 pounds copper sulfate to 100 gallons tt a a a it a tin a a a tt it n 1111 O 1 2 3 April May May 21 12 24 Heavy spraying with lime sulfur arsenate of lead plus 8 pounds copper sulfate to 100 gallons n it n n n n an 11 n it n n n nil P 1 2 3 April May May 21 24 Heavy spraying with lime sulfur arsenate of lead plus 12 pounds copper sulfate to 100 gallons n a a n n n an Check none No treatment NOTE. — All plats except B and C received a winter application of lime sulfur, April 10-14. 158 BULLETIN No. 185 [February, Ben Davis (ft**611 E8^13 ^^ Other varieties CHART 10. — PLAN OF PLATS IN ORCHARD OF MR. G. WARTON, GRIGGSVILLE, 1911 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 159 APPARATUS AND PREPARATION OF MATERIALS In all cases where Bordeaux was used it was made according to the standard formula : 8 pounds of copper sulf ate and 8 pounds of lime to 100 gallons of water. The lime sulfur was made according to the Illinois formula: 50 pounds of lime and 100 pounds of sulfur boiled together in 66 gallons of water until all the sulfur was in solu- tion. For winter strength, lime sulfur was used at the rate of 1 gal- lon in 7 gallons of water (approximately 20 pounds of sulfur in 100 gallons) ; for summer strength, it was used at the rate of 1 gallon in 18 gallons of water (approximately 8 pounds of sulfur in 100 gallons). Grasselli arsenate of lead paste was used at the rate of 4 pounds to 100 gallons of spray. All plats except B and C received a winter applica- tion of lime sulfur. Each plat also received three summer sprays. Application No. 1 was made in the cluster-bud or pink stage ; No. 2 was made at the dropping of the petals; and No. 3 was made about two weeks later. In addition to the three summer sprays above referred to, Plats F and G received three extra summer sprays. The winter spray of lime sulfur was applied with a 200-gallon Gould hand outfit, at about 150 pounds pressure. The summer sprays were applied with a 50-gallon Gould barrel oufit, at about 150 pounds pressure. In all the spraying, double Vermorel nozzles were used. All plats, except where noted otherwise, were sprayed heavily; every part of the tree received a thoro application. CHARACTER OP RECORDS AND METHOD OF MAKING During the season, records were kept of all items of importance. These records included the appearance of the foliage thruout the sea- son in regard to fungi, insects, spray, and vigor. Dropped apples were collected, counted, and examined for various injuries. At pick- ing time two representative trees from each sprayed plat and two from the unsprayed plats were chosen and used in obtaining the data. Two hundred apples were selected from different parts of each tree and examined carefully. The results from the two trees in each plat were averaged together, this average being taken to represent the value of the treatment. Records from the unsprayed trees were made in the same manner. All the apples from each tree in each plat and from each tree in the check row were counted, weighed, and sorted in No. 1 's, No. 2 's, and culls. The No. 1 Ben Davis were not less than 2y2 inches in diameter, were free from scab, with only a slight amount of insect or other in- juries, and of good shape and color. No. 2 apples were 2*4 inches in diameter, occasionally with slight scab, and with not over 20 percent of the apples injured to a slight extent by insects and other causes; 160 BULLETIN No. 185 [February, they were of good shape and color. Apples below these qualifications were classed as culls. WEATHER CONDITIONS The weather from the latter part of April until September was ex- ceptionally hot and dry. The trees were in bloom May 1, and the still, sultry days and nights at that time presented ideal conditions for set- ting of the fruit. All the trees set a good crop and were heavily loaded at picking time. Under the dry conditions of the spring and summer, very little scab developed even on the unsprayed orchards in the vicinity. Sep- tember and October, however, were unusually wet, and during that time sooty blotch developed in great abundance and caused severe damage, especially to unsprayed fruit. At the end of the season, the foliage on the unsprayed trees in the experimental orchard was al- most as healthy in appearance as the foliage on the sprayed trees. VALUE OP A DORMANT-TREE APPLICATION OF LIME SULFUR, AND RELA- TIVE VALUE OF LIME SULFUR AND BORDEAUX AS SUMMER SPRAYS Spraying with lime sulfur while the trees are dormant is the standard treatment for San Jose scale. Many growers, however, ap- ply this spray whether an orchard has scale or not, believing that trees sprayed with lime sulfur while dormant suffer less from scab during the following season than those which are not so sprayed. To determine the value of a dormant-tree application of lime sul- fur, and also to learn the relative value of lime sulfur and Bordeaux as summer sprays, four plats were treated as follows : Plat A: Lime sulfur arsenate of lead, 1st, 2d, and 3d applications (with dormant -tree application of lime sulfur). Plat B: Lime sulfur arsenate of lead, 1st, 2d, and 3d applications (with- out dormant-tree application of lime sulfur). Plat C: Bordeaux arsenate of lead, 1st, 2d, and 3d applications (without dormant-tree application of lime sulfur). Plat D: Bordeaux arsenate of lead, 1st, 2d, and 3d applications (with dor- mant-tree application of lime sulfur). EFFECT ON FOLIAGE The foliage of Plats A, B, C, and D was practically free from scab during the entire season. A slight amount of scab appeared on the unsprayed trees about May 20, but at no time during the summer was the infection serious ; in fact, it was negligible. No apparent differ- ence could be noted between the foliage of Plat A, which received a dormant-tree application of lime sulfur, and Plat B, which did not, for both plats appeared equally vigorous and free from scab. The same was true of Plats C and D, and indicated that under the con- ditions in this orchard a dormant-tree application of lime sulfur was useless. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 161 Plats A and B, which received three summer applications of lime sulfur, and Plats C and D, which were sprayed three times with Bor- deaux, suffered little from scab. Early in the summer a very slight amount of lime-sulfur injury appeared on the foliage of Plats A and B. No appreciable amount of Bordeaux injury was noticed on the foliage of Plats C and D until the latter part of September, when this spray caused the trees to lose a considerable number of leaves. On the whole, Plats A and B, which were sprayed with lime sulfur, had denser and more vigorous-looking foliage and retained it longer than Plats C and D, which were sprayed with Bordeaux. EFFECT ON FRUIT The apples from these plats were picked, sorted, and examined October 20, and the results are presented in Table 41. This table shows that the dormant-tree application of lime sulfur had no effect on apple scab, for it is evident that the amount of scab on Plat A was practically the same as on Plat B, and this is also true for Plats C and D. The results also show that Bordeaux was slightly superior to lime sulfur in the control of apple scab, but the difference is so slight that the two may fairly be considered to have been equal in effectiveness. The unsprayed row shows only 12.37 percent slight scab, which is a small amount of infection for unsprayed apples. This may be explained by the fact that the spring and summer were ex- ceedingly dry and offered conditions unfavorable to scab development. There was a difference, however, between the amounts of fly speck and sooty blotch on Plats A and B and Plats C and D. Plats A and B, sprayed with lime sulfur, showed 19.75 and 22.25 percent flyspeck and 23.5 and 19.25 percent sooty blotch, respectively, as compared with Plats C and D, sprayed with Bordeaux, which showed but .25 and 4 percent flyspeck, and .5 and 4 percent sooty blotch. The un- sprayed row, however, showed 63.87 percent flyspeck and 52 percent sooty blotch. It is probable that a difference in adhesiveness in favor of Bordeaux over lime sulfur explains this difference in control. The amount of codling moth on sprayed plats and on the check row was small. The amount of curculio injury was greater for the lime-sulfur plats than for the Bordeaux plats. A very important difference between the effects of these sprays upon the fruit is shown in the russet columns. Plat C, sprayed with Bordeaux, had .5 percent serious and 41.75 percent slight russet, and Plat D, sprayed with Bordeaux, had 37.25 percent slight russet. Plats A and B, sprayed with lime sulfur, gave, on the other hand, only 2.25 and 4 percent slight russet, respectively. Plats A and B also snowed but a negligible amount of lime-sulfur burn. 162 BULLETIN No. 185 [February, Percentage of picked apples affected by ning >o 10 o o o cq i-; o o o r-i rH | IttB •0 0 10 10 0 cq o t^ cq o Oq ••* rH i~,' ' "* CO 03 snouQg O O IO O O •a-° O IO O IO O O t-I o OS CO q^oui O O IO IO b- o iq cq oq oo rH rH Oq rH CO A°°S O LO O O O co OS •*' cq Cq rH >O jpads/i^i; IO »O IO O b- t~ cq cq o oo oi cq TJH co rH cq «D 1 O IO IO O t- o b- cq 10 eo r-i oq * cq" rH snouag 0 O O O 0 i I] 1

-f ~fi 10 S8[ddl3 p93[0ld •nq IB^OJ, 10 oq o «£>«>: co cq co cq to S8iddij pasfotd •oa IB^OJ, eo oo t- to oq cq to o o to CO t~ rH Tf< OO to U5 t~ IO rH rH -Mr « co co eo 9 ** .s ^ ^ C ** o r-T r-T i-T i-T ^ Treatment fl "a fl S •r1 o T1 -^ ? [S S fl 1 -a "i B K . d Lime sulfur arsenatc of lead wi ter application Lime sulfur arsenate of lead winter application Bordeaux arsenate of lead witho ter application Bordeaux arsenate of lead with application No treatment 4> -5 "o O § cq i-; o g O ItljoITQJ t» oo ' H 1 ^ •3 CO rH W • 5 IB ' enouag O O O B u 10 0 0 Jll b- O IO 2 S nnaitio os co co oq -^ 10 | 3 &, <» t[;ora gnTipoQ ire 10 i-~ cq t^ oo rH »O CO' • o £ O CO E ^ S3 - ^ ^qSi[g B3 ' cq' rH 1 00 snoijgg O O O 3 O enno cq -* Tf S rH « * •+3 t i ^^ 0* a < §1 t S "J^ cq oq ec gi r T "°N •<* oq »o •a! o W 0 S8 ddB pajfDTd to ao t- I1 •nq IB^OJ, OS 00 rH cq co to W ^ to rj< cj & ^ 88] ddu p»j[3id o to o *# 05 00 ° M W H *ou IB^OX IO tD rH rH Z B 0 H eo eo H 3 • aot|BOt[ddy cq~cq~ P 0 i-Ti-T p t-^ i 1 tH > ^CT w s§ o p*3 j^ s ^^ n m o >* & 1 CO CO to r« 1 " enouag o m m o O C<1 (MO ft 8H mo o o t>. o o m S3 m orpnajno OS r-i rH CO fM Cvl GQ in 0) 1 q^ora mo m t- oq m CQ oo es SutTPOO i-i eo "eo re ** 1 qoijoiq 00 00 a ^;oog to enno fM CO N -^ 60 OB s -ON •* eo CD r-i N ej IH co 1 a) r; i ° Sc S f^ T 'OK -* r-l > ei 03 03 ^q ^3^3. C,o 41 % ^^^ m re T3 jj rH a 1 03 OS J5 0) W -5 ® H «H « M M-0 .§ 3 S gre "S r. r. CO 03 03 03 03 03 S C 1^3 n3 173 p ^j JH IH M _S O O O rt O PQM M fc Jd B 03 S PPH 0 6 • EH O § K M & 2s>2S®rt05 i— ' 2 — ^^ ~ r^ *^ £5^ S-4-^ PP^S^SS^^^Oj qj 03 0? 03 03 F-i j PQ rf\ , ~i rQ j I "i PQ i ~i pQ J2 49 03 S 1 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 167 EFFECT ON FOLIAGE During the entire season practically no scab appeared on the foli- age of Plats H, I, J, and K. The foliage of all these plats was equally vigorous thruout the entire season, with the exception of a slight amount of Bordeaux injury which appeared on Plats J and K toward the end of the season. EFFECT ON FRUIT The apples from these plats were picked, sorted, and examined October 20, 25, and 26, and the results are presented in Table 44. All sprays controlled scab almost completely, but flyspeck and sooty blotch were not so satisfactorily prevented. Plat H had 20 percent flyspeck and 25.75 percent sooty blotch; Plat I had 9 per- cent flyspeck and 14 percent sooty blotch ; Plat J, 8 percent flyspeck and 18.5 percent sooty blotch ; and Plat K, 13.25 percent flyspeck and 14 percent sooty blotch. These results, therefore, indicate that where Bordeaux was used a greater number of times than lime sulfur, the amount of flyspeck and sooty-blotch infection was less. Codling-moth injury was very slight on all these plats, even on the unsprayed row. Curculio injury was reduced to some extent on all sprayed trees as compared with the unsprayed trees. Plat H, which received Bordeaux for the first spray and lime sul- fur for the second and third, showed 17 percent slight russet. By subtracting from this amount 2.25 percent, which was the amount of slight russet shown on Plat A, sprayed three times with lime sulfur, it is found that Bordeaux at the first application caused 14.75 percent slight russet. As may be noted, no russet appeared on the unsprayed row. Plat I, sprayed with Bordeaux for the first and second appli- cations and with lime sulfur for the third, showed 49.5 percent slight russet. Since 14.75 percent slight russet has been attributed to the first application of Bordeaux, this amount deducted from 49.5 per- cent slight russet leaves 34.75 percent slight russet due to the second Bordeaux and the third lime-sulfur sprays. Sprays 1, 2, and 3 together caused only 2.25 percent injury when lime sulfur was used thruout. Therefore, at least 32.5 percent of the russet may be attributed to the second application of Bordeaux. Plat J showed 39.5 percent slight rus- set. It has just been stated that 32.5 percent slight russet came from the second application of Bordeaux. By subtracting this amount from 39.5 percent, the amount of slight russet shown on Plat J, it is found that the third application of Bordeaux caused only 7 percent slight russet. Plat K, which received lime sulfur for the first and second applications and Bordeaux for the third, showed 9.5 percent slight 7-usset, 2.25 percent of which was caused by lime sulfur, the balance 7 percent having been caused by Bordeaux. To sum up the discus- sion on russet, these results show that the greatest amount of russeting 168 BULLETIN No. 185 [February, from Bordeaux occurred at the second application, and that a small amount came from both the cluster-bud spray and the spray applied two weeks after the fall of the petals. A negligible amount of lime- sulfur burn occurred on Plats H and K. Plats H and A produced the highest percentages of No. 1 apples. The fruit from Plat H had the best color, altho the apples from all of these plats had good color and fair finish. ARSENATE OF LEAD ALONE AS A FUNGICIDE To determine the fungicidal value of arsenate of lead alone when used primarily as a spray for codling moth, plats were sprayed as follows : Plat L: Bordeaux arsenate of lead, 1st application; arsenate of lead, 2d and 3d applications. Plat M: Lime sulfur arsenate of lead, 1st application; arsenate of lead, 2d and 3d applications. EFFECT ON FOLIAGE No appreciable amount of scab appeared on the foliage of Plats L and M. The foliage was very vigorous during the entire season, and practically no foliage injury resulted from the use of the sprays. EFFECT ON FRUIT The apples from these plats were picked, sorted, and examined October 20 and 25, and the results are presented in Table 45. These results show that the sprayings given Plats L and M were effective in controlling scab. Plat L had 14 percent flyspeck and 24.5 percent sooty blotch as compared with Plat M with 21 percent flyspeck and 35 percent sooty blotch. It is evident that arsenate of lead ap- plied at the second and third applications had little effect on these diseases. The results seem to show that lime sulfur arsenate of lead and Bordeaux arsenate of lead applied at the first spraying reduced the amount of flyspeck and sooty-blotch infection, but that arsenate of lead alone applied at the second and third applications had little or no fungicidal value. Codling-moth and curculio infestation was reduced on both plats. Plat L showed 10.5 percent slight russet, and Plat M only 1.25 percent slight russet. It is evident, in the case of Plat L, that the russet was caused by the Bordeaux, which was used at the first application. The fruit from both Plats L and M had excellent color and finish, exceeding in this respect the apples from any of the other plats in the orchard. It was evident that the arsenate of lead stimulated color. Plat M had 84 percent No. 1's and Plat L, 77 percent of the same grade. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 169 ning M snouag t^ora snouag I 'ON sajddB •nq to 03 qj « fl H m< CQ tung 0 IO 0 10 0 o b- c> cq o rH i-H £ T3 EJQ * •3 O IO C IO O iq cq o sq o rH t>^ eo oq cq co to -2 o o 0 " enoTieg O O 0 OO s 8 Oi onnoano O IO IO O O t-^ »O rH o' CO a 03 ^3 -

  • o 8. 5 § spadsA1^ O IO »O >O b- LO cq b- b- oo o> «o oq' c» co' rH rH 5O 8 & AH ^ ^Sifg O O O O b- O O O O CO " r-i CM' I-H 02 snouag O O O O O to BIPO cq ^^ ^i co ^^ cuo 1 fl r a> s 'ON 1 oo eo co oo -H iH cq i-i rH eo 1 AH tt T 'ON o co co 01 10 00 b- 00 b- to se ddB p83[3Td •nq fB^oj^ CO CO »O b- rH O3 rH CO i-H co co cq co <£> SQ dd^ pas[DTd •ou IB^O,!, sq 1-1 <3i co cq » 3: May 29 Bordeaux " " " C 1: April 27 Lime sulfur arsenate of lead 2: May 10 Bordeaux 3: May 29 Lime sulfur " D 1: April 27 Lime sulfur arsenate of lead 2: May 9 } } » > t » } > 3: May 29 > > > > > > » » E 1: April. 27 Bordeaux arsenate of lead 2: May 9 Lime sulfur " " " 3: May 29 Bordeaux F 1: April 27 Bordeaux arsenate of lead 2: May 10 » > > } ) » 3: May 29 » » » a 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 173 Plat Appli cation Treatment G 1: April 27 Bordeaux arsenate of lead 2: May 10 Lime sulfur " " " 3: May 29 » ) ) » » » H 1: April 27 Bordeaux arsenate of lead 2: May 10 > ! ) } » » 3: May 29 Lime sulfur " " " I 1: April 30 Copper ferroeyanide arsenate of lead, 1-1-4—100 2: May 12 " » i_i_4_ioo 3: May 31 » » 1_1_4_100 J 1: April 30 Copper ferrocyanide arsenate of lead, l%-l%-4-100 2: May 12 " " 1V2-1V2-4-100 3: May 31 l%-l%-±-100 K 1: April 30 Copper ferrocyanide arsenate of lead, 2-2^4-100 2: May 12 " » 2-2-4-100 3: May 31 " " " " " 2-2-4-100 L 1: April 30 Copper ferroeyanide alone, 1-1-100 2: May 11 " 1-1-100 3: May 31 " 1-1-100 M 1: April 30 Copper ferroeyanide alone, 1%-1%-100 2: May 11 " 1%-1%-100 3: May 31 1%.-1%-100 N 1: April 30 Copper ferrocyanide alone, 2-2-100 2: May 11 ' ' 2-2-100 3: May 31 " " 2-2-100 O 1: April 27 Lime sulfur alone 2: May 10 » » » 3: May 31 y > > > » P 1: April 27 Arsenate of lead alone, 4—100 2: May 10 » >' 4-100 3: May 31 " " " " 4-100 Q 1: April 30 Lime sulfur (1 in 36) arsenate of lead 2: May 9 )t » 1 ' ' 36 " " " 3: May 31 » > > 1 " 36 " " " R 1: April 30 Lime sulfur (1 in 24) arsenate of lead 2: May 9 » » 1 ' ' 24 " " " 3: May 31 > j j j 1 " 24 " " " S 1: April 30 Lime sulfur (1 in 14) arsenate of lead 2: May 9 » }> 1"14 " " " 3: May 31 » » • 1 ' " 14 " " " Check none No treatment In laying out these experiments the trees were divided into twenty- one plats of eight or nine trees each, and a check or unsprayed row was left thru the entire length of the orchard. These plats were grouped, and each group was sprayed as nearly under the same con- ditions as possible, so that the plats in each group should be strictly comparable. APPARATUS AND PREPARATION OF MATERIALS In all cases where Bordeaux was used in these treatments it was made according to the standard formula: 8 pounds copper sulfate and 8 pounds lime to 100 gallons of water. The lime sulfur was made according to the Illinois formula: 50 pounds lime and 100 pounds sulfur, boiled together in 66 gallons of water until all the sulfur was 174 BULLETIN No. 185 [February, (f))Ben Davis (WBen Davis Bother varieties ^ W Check \J CHART 11. — PLAN OF PLATS IN ORCHARD OF MR. F. TURNBULL, GRIGGSVILLE, 1912 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 175 in solution. Unless otherwise stated this was used at the rate of 1 gallon in 18 gallons of water (approximately 8 pounds of sulfur in 100 gallons). Copper ferrocyanide was made from equal amounts of copper sulfate and potassium ferrocyanide, diluted in equal parts of water, and then run together; Grasselli arsenate of lead paste was used at the rate of 4 pounds to 100 gallons of spray. SPRAY DATES All sprays were applied with a Friend power spray outfit at 150 to 175 pounds pressure. Double Vermorel nozzles were used. Three applications were made : the first in the cluster-bud stage ; the second at the dropping of the petals ; and the third about three weeks later. CHARACTER OP RECORDS AND METHOD OP MAKING During the season records were kept including the appearance of the foliage thruout the season in regard to fungi, insects, spray injury, and vigor. Dropped apples were counted and examined for various injuries. At picking time four representative trees from each sprayed plat and seven from the unsprayed row were selected and as many of the apples as the sorting table would conveniently hold were taken from all parts of each tree ; from these, 200 representative apples were selected and examined carefully. The results from the four trees in each plat were averaged, and the average taken to indicate the value of the treatment. The fruit from the seven unsprayed trees was re- corded in like manner. All the apples from each tree in each plat, and from each tree in the check row, were counted, weighed, and graded according to the standard adopted by the Illinois State Horticultural Society.1 WEATHER CONDITIONS The weather during the late spring and early summer was very wet and rather cool. However, at no time after the trees started their growth did the temperature drop below 40 degrees. The trees were in full bloom May 4, and a heavy rain occurred during that night. RELATIVE VALUE OF LIME SULFUR AND BORDEAUX As a further test of the relative value of lime sulfur and Bordeaux in this section of the state, plats were again sprayed with these mate- rials as shown in Table 47. EFFECT ON FOLIAGE About May 15 the slightly elevated green spots of apple scab be- gan to appear on the foliage of the unsprayed trees. On examining the foliage on Plats D and F, practically no scab was found; this 'See footnote, page 60. 176 BULLETIN No. 185 [February, was true for the rest of the season, indicating that lime sulfur and Bordeaux were equally effective in their control. This was not true, however, in regard to leaf spot (Sphaeropsis malorum), which was more in evidence on the foliage of the trees sprayed with Bordeaux than on the trees sprayed with lime sulfur. The unsprayed trees showed a great deal of leaf spot due to this fungus. A little Bor- deaux injury appeared on the foliage in the form of small brown spots about four days after the second application. The trees sprayed with Bordeaux suffered from an. epidemic of yellow-leaf June 25, and a second outbreak occurred August 10, reducing the amount of foliage materially. Thruout a considerable part of the season these trees were easily recognized by the scanty development of their leaves. The trees sprayed with lime sulfur, on the other hand, retained a dense, deep green foliage, and showed practically no spray injury at any time during the season. EFFECT ON FRUIT The apples from these plats were picked, sorted, and examined on October 14 and 15, with the results presented in Table 47. Scab. — The data presented show that Bordeaux was slightly super- ior to lime sulfur in the control of apple scab, but the difference, .15 percent serious and 4.25 percent slight scab, is so slight that the two may be considered to have been equal in efficiency. The unsprayed row showed 68.36 percent serious and 21 percent slight scab, indicat- ing that both Bordeaux and lime sulfur were very effective in the control of this disease. Flyspeck and sooty blotch appeared on the fruit of the unsprayed trees late in September, but the attack, as the records indicate, was not very serious in character. All diseases were well controlled by both lime sulfur and Bordeaux, the latter giving slightly better results. Codling Moth and Curculio. — The arsenate of lead in both sprays effectively prevented damage from codling moth. The amount of in- jury done by the plum curculio was reduced from a total of 72.14 percent on the unsprayed trees to 12.12 percent on the lime-sulfur plat and 9.24 percent on the Bordeaux plat. Nearly all of the cur- culio injury recorded from these sprayed plats was in the form of healed-over egg punctures made by the spring generation of curculio. while most of the injury on the unsprayed trees was caused by the feeding punctures of the new brood. Russet. — A very important difference between the effects of these sprays upon the fruit is shown in the russet columns. There was 23.4 percent serious and 53.5 percent slight russet on the trees sprayed with Bordeaux, as compared with 1 percent and 12.75 percent injury on the trees sprayed with lime sulfur. Reference to the amount of russet on the unsprayed trees will show that 4.07 percent serious and 11.2 percent slight russet may have been caused by something other 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 177 Percentage of picked apples affected by 4* I CO f§ »iSns VO O O L~ Id t^ ao »-i i-H snoyiat,- •O >•$ JSf «O •* (M CO 04 04 00* (D enouag Percentage grades siPO >*l i-l i-l iHU3 S *°N Is* CO ^t* c co ost- ^J10. •-; ""l5^ o Tj5 T»! OQ coco' ' b^ «d r-J 1C ^J* CO rH ^* 1C CC ^* rH 3 snoj.iag t- O OSO OO 1- t-t- CO Tji CO r-i rH CO t^ O •* iHOQ rH ^ T»i eg ro c to r- ic i^ «o 88 rddra paJTDld eg t"- r~*o ici^» co icos •nq IBJOJ, 00 o' rH jo hJ ^! «O O Tji co co "^ic corn eg coco sa [dd« •on pajjoid IB^°iI t-- C-l CO rH OS O CO O 00 CO CO IOCO CgrH 01 CM-* ic •«*< fflt~ iceg co co«o B UOI^B oilddy co co co coco eo eo co® eg egeg egcg eg i— 1 r~l —T r-Tr-T r-TrH " O o3® 73O c3® r; O c3cd® Cd® « i i 03 OCS OCS OCS ocS OOCS ooS j 1 a I* I" 1^ 1* II * I * ^ I 1 E- i i D 03S c«S oJS rti= rtrtS c3S w o cq - r-j m o o c r-i t>T eo o»s 0 o c q >o o q 00 CO CO Oi t» ^^ ^H OQ (M (M C4 rH 05 CO ^ ^ ^* CO rH ^^ rj< oa •* oq -^ oq eo sajdds pajpid •ou i^o'i o o oo eo o o ao «O •* O O O5 OS •* •* rH CO 0 rH -* Tjt b- ^ b- CO b- CO (£> snoTiBoijddy fo eo co co co eo s> o>ilTil%»tlll|»,x;x|i4 2°00*rl SOJg^J20^2 d« S^J**^*^^**^^!*^^! Ji fell hllftll fell hill ysii'l!sy«l!i|if g.rt-A^og.cS^.g.&Og.cS^g-POo J O O O O O £ 4f ••- £ Jri H rH ^ 3 M » 1 11)16] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 183 excellent color, tho it was small and scabby. The arsenate of lead had a stimulating effect on color. It must be concluded, therefore, that under the conditions which prevailed in the Griggsville experiments in 1912, copper ferrocyanide, as a summer spray, was practically useless. EFFECT OF THE ADDITION OF ARSENATE OF LEAD TO LIME SULFUR The addition of arsenate of lead to lime-sulfur solution causes a chemical reaction which changes the composition of a small amount of each.1 It is also known that the addition of arsenate of lead to lime sulfur affects the fungicidal value of that spray.1 To determine the effect of the addition of arsenate of lead to lime sulfur under the conditions existing in this part of the state, three plats were treated as shown in Table 50. EFFECT ON FOLIAGE On the foliage of Plat 0, which was sprayed with lime sulfur alone, there was a slight infection of scab, but on the foliage of Plat P, sprayed with arsenate of lead alone, there was considerable infection, tho less severe than on the check row. The foliage of Plat D, sprayed with lime sulfur arsenate of lead, showed practically no scab. There was some leaf spot on Plats 0 and P, but Plat D showed almost no infection with this fungus. The addition of arsenate of lead to lime sulfur apparently increased the fungicidal value of that spray. There was some insect work on the foliage of Plat 0 due to the absence of arsenate of lead, and the leaves were not so deeply colored as those on the trees of Plats P or D. Plat P showed a little foliage injury in the form of brown edges and tips, but the amount was al- most negligible. EFFECT ON FRUIT The apples from these plats were picked, sorted, and examined October 11 to 12. The results as presented in Table 50 show that lime sulfur when used alone controlled scab very effectively on the fruit. Of the apples sprayed with arsenate of lead alone, 37.5 per- cent were infected with serious scab, and 31.5 percent with slight scab. Arsenate of lead, however, increased the fungicidal value of lime sulfur, for in comparing the results for scab on Plat 0, sprayed with lime sulfur alone, and Plat D, sprayed with lime sulfur and arsenate of lead, we note a small difference in favor of the latter plat. There was a little more flyspeck and sooty blotch on Plat O than on Plat P, owing possibly to the fact that Plat 0 was located in a slightly lower part of the orchard. Arsenate of lead controlled codling moth perfectly, while. lime sul- fur had no effect upon it. In curculio injury a decided reduction may be noted in all sprayed plats as compared with the check row. 1E. Wallace, N. Y. (Cornell) Agr. Exp. Sta. Bui. 289, p. 146. 184 BULLETIN No. 185 Percentage of picked apples affected by 43 1 3 M WStig o o 10 o ** rH I-; M 00* »O Cq' r-i rH iH snoTiag O O O b- »o 10 o o i-i rH •* Curculio ?q§ns O IO t- t- O O eo •«*' o co eq rH iH r-l enouag o 10 in t- >o t- cq in -o oJ rH ec' rH »O M 25 |1 ePTS 0 O (MO OJ O rH O * r-5 X^BQ 00 0 CO 00 0 •* 10 '« Mj §o GQrQ W^TIS ON t^ t~ oa r-j oo o 00* CO r-H M enouag O 0 O i-1 O O O b- ' CQ jtfj B| CO W^ns o o o o ei * © snoiiag O O Cd TP o cj '•*'-! I o 0& wSjis LO O ; 0O •* 4.0 fO sajddra paspid •ou iino'i «3 OO rH OO rH I— CO Tt< t~ Tf( 00 -* t^ «O l~ «D suopBDiiddy eo eo eo ® ccToT cT o »- - », fl rH rH rH Treatment Lime sulfur alone Arsenate of lead alone. . . Lime sulfur arsenate of lead No treatment "of s M OPMQ | 3 1 ijqSiIg »O O IO O O i>« eo b- o cq oi C3> c\i eo r-5 rH rH rH rH 3 M snowag o o o to b» rH rH C5 b- O rH rH l-5 C<" Tj? cq rH 05 rH £ 0 a 3 ,^8 tC O b- Ob- t>° rH O 00 OO rH rH rH ff 3 3 M i g 1 •« eo t> 1 snouag cq o 10 ob- rH rH " CO >O § 3 EC 9 'ft Pi be 95 OPTS cq o cq o o rH C5 rH O O "rH 5J W> S3 n3 o> xA.O O O O O CO 0 0 O 0 -* 'eo' IIMENT 2 'ft o co eo 3 5 89 •o i IB^OX rH IO -H 00 00 eo O fO oo ^f co oo oo cq •* § CQ H o 1 OOT^T solidly co eo co eo ® .. ^ ^ -. C cq eq eq cq o i-T i-T r-T i-T H 1 t rH IO W 3 « •«! H « i § i s M d 2 H 03*03 "o 3 ' 0 3 §00 * 8,3 §°° '§r§ c^3oc^^oe^3oeo3Q Q( — i O' — " ^^ ' — '"*"* ^ ft "3 % f^'& 3 i=iH'e3 5 ^"oi § *3 O "3 O "3 O "3 """ O -H CQ p. O> co p to co », o M ^^5 eo rHQjOC^OCOOCQ^O i u 1 s ,M 0? M fl CO | 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 185 The reduced amount of injury on Plat P was due to the arsenate of lead. Just why the amount of cureulio injury on Plat 0 was re- duced in comparison to what appeared on the unsprayed row would be difficult to explain, and yet it is important. Apparently the lime sulfur acted as a repellent. Scab reduced the percentage of No. 1 apples in Plat P, sprayed with arsenate of lead alone, in comparison with Plat 0, where lime sulfur alone was used. The fruit from Plat P had a better color and smoother finish than that from Plat 0. Arsenate of lead again showed a stimulating effect on color and finish. RELATIVE VALUES OF VARIOUS STRENGTHS OF LIME SULFUR In the preceding experiments in which lime sulfur was used, the amount of sulfur in solution was approximately 8 pounds to each 100 gallons of spray. To determine the efficiency of various strengths of homemade lime sulfur, four plats were treated as shown in Table 51. EFFECT ON FOLIAGE All the sprays held both scab and leaf spot in check; there Avas practically no scab during the entire season on all four plats. The foliage was similar in appearance, — very dense, and dark green in color. The different sprays had a decidedly stimulating effect on the size and smoothness of the leaves, and caused almost no injury. The foliage of the sprayed plats remained on the trees until after No- vember 7, while that of the unsprayed row was completely gone by October 10. The retention of this dense green foliage so late in the sea- son seemed to increase the size and vigor of the fruit buds, as the differ- ence in size between the buds on these plats and those on the plats which suffered considerable foliage injury from spray was very apparent. EFFECT ON FRUIT The apples from these plats were picked, sorted, and examined October 9 to 11. The results as presented in Table 51 show that the spray given Plat S controlled scab on the fruit almost perfectly, there being but .12 percent severe scab and 1 percent slight scab. Plats Q, R, and D show about the same percentages of scab, only slightly more than Plat S. Flyspeck was controlled on all plats except Plat D, where the injury was negligible. All sprays controlled sooty blotch with the exception of those used on Plats D and R, where the infection was very slight. Codling-moth control was almost perfect on all plats. Injury from cureulio was reduced materially by all the sprays. All plats produced a high percentage of No. 1 fruit, Plat S the highest. The fruit from all these plats took on a very high color and a smooth waxy finish and was of good size. The apples en Plat S seemed to have a deeper and better distributed color than those on the other 186 BULLETIN No. 185 [February, plats. On all plats the stimulating effects of lime sulfur and arsenate of lead on the color and smoothness of the fruit was further demon- strated. These plats were the best of any in the orchard on account of the freedom of the fruit from fungi and insects, the large size, high col- or, and smoothness of the fruit, and the heavy, dense green foliage. SUMMARY OF EESULTS AT GRIGGSVILLE, 1912 1. Homemade lime sulfur containing 8 pounds of sulfur and 4 pounds of arsenate of lead to 100 gallons proved equal to Bordeaux arsenate of lead, 8-8-4-100, as a spray for apple scab, and the two sprays were practically equal in their control of flyspeck and sooty blotch. 2. Three applications of Bordeaux arsenate of lead caused severe injury to foliage and badly russeted the fruit, while lime sulfur ar- senate of lead did not injure the foliage seriously nor russet the fruit. 3. Lime sulfur arsenate of lead had an invigorating effect on the foliage and a stimulating effect on the color and size of the fruit, be- sides giving it a very waxy finish. 4. Some russeting of the fruit resulted from each of the three applications of Bordeaux. 5. Bordeaux injury to fruit and foliage developed under cool, wet conditions. 6. The severe foliage injury caused by Bordeaux had a detri- mental effect on the development of the next-year's fruit buds. The buds on lime-sulfur trees were large, plump, and well developed, while the buds on the trees sprayed with Bordeaux were smaller and ap- parently not so well developed. 7. Copper ferrocyanide proved practically useless as a fungicide or insecticide. 8. Lime sulfur arsenate of lead was slightly more effective in controlling scab, flyspeck, and sooty blotch than lime sulfur alone. The arsenate of lead may have increased the adhesiveness of the lime sulfur. 9. Fruit sprayed with arsenate of lead alone had a higher color than that sprayed with lime sulfur alone, indicating that arsenate of lead stimulates color. 10. Arsenate of lead alone had some fungicidal value and caused but a negligible amount of foliage injury. 11. Various strengths of homemade lime sulfur containing 4, 6, 8, and 10 pounds of sulfur together with 4 pounds of arsenate of lead to 100 gallons, controlled scab, flyspeck, and sooty blotch effectively, and gave excellent foliage and highly colored, large, smooth fruit. The 10-pound strength (10-100) was the most efficient, controlling scab almost perfectly; less than 2 percent of the fruit was infected with scab ; and the color of the fruit was deeper and better distributed. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 187 GENERAL SUMMARY BY B. S. PICKETT In this summary the writer has attempted to answer the questions presented in the introduction (pages 50 and 51), to point out certain facts which are not specifically mentioned in the questions referred to, and to make recommendations for the general spraying of apple orchards in Illinois. Where the material would permit, results from the various experiments are tabulated for convenient, reference. The data answering several of the questions, however, could not be tabu- lated advantageously, and such results are presented in the form of brief summaries or statements from the annual reports of the individ- ual experiments. SUMMARY OF DATA 1. What is the general effectiveness of applications of standard spray mixtures, including Bordeaux, lime sulfur, and arsenate 'of lead in the control of fungi and insects on the apple? No fact stands out more distinctly in a study of the data presented, in the reports included in this bulletin than the general effectiveness of spraying over no spraying. Even under the most unfavorable cir- cumstances, some degree of benefit has resulted from the application of all of the standard sprays in every series of experiments and in every year of the experimentation. Year after year the sprayed plats have been conspicuous by their more healthy and vigorous foliage and by the freedom of their fruit from insects and diseases. Of necessity the benefits from spraying have varied more or less from season to season. In 1911 both diseases and insects were conspicuous by their comparative absence. Even unsprayed orchards produced consider- able fruit of good quality. Under such conditions the best possible effects of sprays are not fully demonstrated. Nevertheless, even in 1911, spraying proved its superiority over failure to spray in every case experimented upon. Tables 52 and 53 present the general results of four years' experi- mentation in an attempt to answer the above question. Every result thruout the reports previously presented which bears directly upon this subject has been included in these tabulations. . It will be seen from Table 52 that the smallest control exercised over apple scab as a result of spraying at least three times with Bordeaux or Bordeaux in combination with arsenate of lead amounts to 67 percent, and that the largest control amounts to 98 percent. In six experiments out of ten, 90 percent or over of all the scab which might have appeared in the sprayed plats was prevented as a result of spraying with Bordeaux or Bordeaux in combination with arsenate of lead. 188 BULLETIN No. 185 [February, TABLE 52. — GENERAL EFFECTS OF THE STANDARD FUNGICIDES, BORDEAUX AND LIME SULFUR Fungicide Year Place Experi- menter Table Percentage of fruit saved from scab by spray 1 Percentage scab con trolled as compared with checks Bordeaux '09 Griggsville L.E.F. 26 47 to 56 75 to 90 Bordeaux '11 Neoga O.S.W. 6 51 to 61 67 to 80 Bordeaux '11 Neoga O.S.W. 7 67 79 Bordeaux '11 Centralia L.E.F. 28 37 to 43 84 to 98 Bordeaux '11 Griggsville A.J.G. 41 12 98 Bordeaux '12 Neoga O.S.W. 14 72 to 87 73 to 88 Bordeaux '12 Flora W.A.K. 21 14 93 Bordeaux '12 Anna L.E.F. 30 33 to 34 87 to 90 Bordeaux '12 Anna L.E.F. 31 57 to 71 70 to 87 Bordeaux '12 Griggsville A.J.G. 47 66 97 Lime sulfur '09 Griggsville L.E.F. 24 17 to 56 19 to 60 Lime sulfur -'10 Neoga O.S.W. 1 6 to 85 6 to 85 Lime sulfur '11 Neoga O.S.W. 6 25 to 48 33 to 63 Lime sulfur '11 Neoga O.S.W. 7 55 65 Lime sulfur '11 Centralia L.E.F. 28 39 to 40 89 to 91 Lime sulfur '11 Griggsville A.J.G. 41 11 91 Lime sulfur '11 Griggsville A.J.G. 46 11 to 12 91 to 100 "Lime sulfur '12 Neoga O.S.W. 14 72 to 84 72 to 84 Lime sulfur '12 Neoga O.S.W. 17 41 to 52 45 to 57 Lime sulfur '12 Flora W.A.E. 21 15 100 Lime sulfur '12 Anna L.E.F. 30 26 to 34 70 to 92 Lime sulfur '12 Anna L.E.F. 31 51 to 65 62 to 80 Lime sulfur '12 Anna L.E.F. . 33 39 to 56 47 to 67 Lime sulfur '12 Griggsville A.J.G. 47 70 80 Lime sulfur '12 Griggsville A.J.G. 51 78 to 88 88 to 99 Lime sulfur exercised varying degrees of control, running from as low as 6 percent to as high as 100 percent. In two experiments out of fifteen, 100 percent control was obtained. In six experiments out of fifteen, lime sulfur exercised a control running above 90 per- cent. In five cases this fungicide prevented less than 50 percent of the possible damage from apple scab. In no single case, however, did it fail to exercise some control over this fungus, and in those experi- ments where the poorest control was obtained, certain plats showed an effectiveness varying from 57 to 85 percent. In the twenty-nine experiments included in Table 53, arsenate of lead did not fail to exercise some degree of control over codling moth and curculio in some one or more of the plats included in each of the experiments. In four cases, however, certain sprayed plats in the experiment showed more injury than the check plats. It will be observed, however, that in every one of these four cases the total infestation of codling moth was very small, the largest loss due to failure of the spray to control the insect amounting to 3 percent of the entire crop. Under the circumstances in which these slightly inconsistent results appear, the inconsistency must be attributed to unequal infection rather than to ineffectiveness of the spray. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 189 TABLE 53. — GENERAL EFFECT OF THE STANDARD INSECTICIDE, ARSENATE OF LEAD, ALONE OR IN COMBINATION WITH VARIOUS FUNGICIDES -*> • • bO'O "S i* . oj t» 1 '3 'o «w ° 0 ffl tn 0 ° n 8 ,2 •f r£5 &UDC*H 2 tUO5*-! S So1*-! tUC1*-! ® QJ M CO 03 M 03 ° o 03 C3 0 S H 8 8a g | g |Iil 1 PH £ £ £ '09, Griggsville L.E.F. 23 5 to 12 100 21 to 35 21 to 43 ;09, Griggsville L.E.F. 25 14 82 No control '09 Griggsville L.E.F. 26 17 to 19 85 to 95 25 to 30 27 to 32 '09 Griggsville L.E.F. 27 4 to 18 33 to 95 10 to 50 10 to 64 '10 Neoga O.S.W. 1 20 to 28 71 to 100 62 to 80 62 to 85 '10 Neoga O.S.W. 4 10 to 26 36 to 93 32 to 80 32 to 80 '10 Neoga O.S.W. 5 14 to 25 oO to 89 46 to 81 46 to 81 '11 Neoga O.S.W. 10 -2 to 1 -33 to 17 -1 to 6 -17 to 100 '11 Neoga O.S.W. 11 5 to 16 31 to 100 -4 to 12 -27 to 80 '11 Centralia L.E.F. 28 7.8 65 0 to 14 Oto 88 '11 Griggsville A.J.G. 41 2 to 3 42 to 74 13 to 34 24 to 61 '11 Griggsville A.J.G. 42 -2 to 3 -50 to 75 11 to 24 20 to 44 '11 Griggsville A.J.G. 43 0 to 3.5 Oto 90 24 to 33 44 to 61 '11 Griggsville A.J.G. 44 -1 to 3 -25 to 75 14 to 24 26 to 44 '11 Griggsville A.J.G. 45 2 to 3 50 to 75 15 to 18 28 to 34 '11 Griggsville A.J.G. 46 -3 to 3 -75 to 75 '12 Anna L.E.F. 30 1 to 18 2 to 36 12 to 19 32 to 51 '12 Anna L.E.F. 31 24 to 28 86 to 93 4 to 19 11 to 51 '12 Anna L.E.F. 35 16 to 32 34 to 63 17 to 19 46 to 51 '12 Anna L.E.F. 36 •16 to 27 53 to 90 -13 to 5 -35 to 16 '12 Anna L.E.F. 37 2 to 18 4 to 38 -5 to 13 -14 to 35 '12 Anna L.E.F. 38 18 to 24 60 to 80 8 to 14 22 to 38 '12 Anna L.E.F. 39 2 to 24 4 to 51 5 to 19 14 to 51 '12 Anna L.E.F. 40 18 to 27 60 to 90 4 to 8 8 to 16 '12 Griggsville A.J.G. 47 3.43 100 60 to 63 83 to 88 '12 Griggsville A.J.G. 48 3.2 to 3.4 93 to 100 53 to 64 74 to 89 '12 Griggsville A.J.G 49 3.43 100 60 to 63 83 to 88 '12 Griggsville A.J.G. 50 3.43 100 48 to 60 67 to 83 '12 Griggsville A.J.G. 51 3.43 100 60 to 64 83 to 89 The general effectiveness of the spray will be seen when it is noted that in fifteen experiments of the twenty-nine tabulated, 90 percent or better control of the codling moth was obtained in some of the plats included. Curculio was less thoroly controlled by arsenate of lead than was codling moth. Nevertheless in only six of the experiments were there any plats which failed to show some degree of prevention of injury by reason of the application of the spray. Eleven experiments out of the twenty-nine included some plats in which 80 percent or more of the injury was prevented by the application of the spray. 2. What are the relative values of Bordeaux and lime sulfur as sprays for tJie apple ? Table 54 presents a summary of the comparative values of Bor- deaux and lime sulfur in the various experiments during 1909-12. 190 BULLETIN No. 185 TABLE 54. — COMPARATIVE EFFECTIVENESS OF BORDEAUX AND LIME SULFUR AS SUMMER SPRAYS FOR APPLES Year Place Experimenter Page Lime sulfur compared with Bordeaux As regards '09 Griggsville L.E.P. 121-124 Inferior Scab on fruit '10 Neoga O.S.W. 61-62 Inferior Scab on foliage 62 Superior Vigor and abundance of foliage '10 Centralia L.E.F. 128 Equal Scab on foliage 128 Superior Spray injury to foliage '11 Neoga O.S.W. 75-87 Inferior Scab on fruit 75-77 Inferior Color of fruit 74 Inferior Spray injury to foliage '11 Centralia L.E.F. 138 Superior Eusseting of fruit 133-134, Superior Vigor and abundance of foliage. 138 spray injury to foliage 134-137 Inferior Scab, blotch, and sooty blotch on fruit '11 Griggsville A.J.G. 161-162 Equal Scab on fruit 161-162 Inferior Flvspeck and sooty blotch on fruit 161-163 Superior Eusseting, color, and finish of fruit 160-161 Equal Scab on foliage 160-161 Superior Vigor and abundance of foliage '12 Neoga O.S.W. 94 Inferior Scab on fruit 94 Inferior Amount of surface colored 94 Superior Finish of fruit 94 Equal Yield of No. 1 apples 92 Inferior Scab on foliage '12 Flora W.A.E. 111 Equal Scab on fruit 116 Superior Spray injury to foliage 117 Superior Eusseting of fruit 111 Inferior Blotch on fruit 108 Equal Scab on foliage 108-111 Superior Injury to foliage '12 Anna L.E.F. 145 Inferior Scab and sooty blotch on Jona- than apples 145 Inferior Scab and sooty blotch on Wine- sap apples 145 Superior Eueset of Jonathan apples 148 Superior Eusset of Winesap apples 143 Superior Injury to foliage '12 Griggsville A.J.G 176 Inferior Scab, sooty blotch, and fly- speck of fruit 176-178 Superior Eusset on fruit 178 Superior Color, size, finish, and grading of fruit 175 Equal Scab on foliage 176 Superior Leaf spot From the above tabulation it will be seen that Bordeaux has in most of the experiments proved superior to lime sulfur as a fungicide. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 191 In six different experiments Bordeaux proved superior to lime sulfur in the control of scab on the fruit ; in two experiments the fungicides were equal in this respect. Lime sulfur, however, was not superior in any case. In two experiments Bordeaux proved superior to lime sul- fur in the control of scab on the foliage. In four experiments the con- trol of scab on the foliage was equal. Lime sulfur was in no case su- perior to Bordeaux in the control of scab on the foliage. In six ex- periments Bordeaux was superior to lime sulfur in the control of blotch, sooty blotch, and flyspeck fungi. In no case was lime sulfur superior or equal to Bordeaux in the control of these diseases. In only one experiment is lime sulfur reported as showing a control superior to Bordeaux on a fungous disease of the foliage. In the experiments at Griggsville in 1912, leaf spot (Sphaeropsis malorum) was more in evi- dence on the trees sprayed with Bordeaux than on the trees sprayed with lime sulfur. Lime sulfur, however, proved superior to Bordeaux in the major- ity of the experiments in respect to spray injury to the foliage and fruit. In nearly all cases the foliage on the trees sprayed with lime sulfur was more vigorous than the foliage on the Bordeaux-sprayed trees, and in most cases the lime-sulfur-sprayed fruit was of superior finish and color. In seven experiments out of nine, lime sulfur proved superior to Bordeaux in its effect on the vigor and abundance of foliage or in its effect on spray injury. In 1911 in the Neoga experiments, lime sul- fur proved inferior to Bordeaux in relation to spray injury to the foliage, and in 1912 at the same place, the vigor and abundance of foliage on the lime-sulfur and Bordeaux-sprayed plats were equal. In five experiments lime sulfur was superior to Bordeaux as regards rus- seting of the fruit. With the exception of the experiments at Neoga in 1911 and 1912, lime-sulfur-sprayed fruit was more brightly colored and more attractive in appearance than Bordeaux-sprayed fruit. In reporting on the experiments at Neoga in 1911 and 1912, 0. S. Wat- kins, in charge of these experiments, calls attention to the fact that while lime-sulfur-sprayed apples had a higher finish and brighter color than Bordeaux-sprayed apples, the color was not distributed over so much of their surface as in the Bordeaux-sprayed apples. He concludes that the Bordeaux-sprayed apples had more color as a whole than the lime-sulfur-sprayed apples, tho this color was not so attrac- tive, especially as the apples hung on the trees. The general conclu- sion, however, which must be derived from a summary of all the re- sults, is that the lime-sulfur-sprayed apples were enough more attrac- tive than the Bordeaux-sprayed apples to give them a higher com- mercial value on the market. With two exceptions lime-sulfur- sprayed apples graded a larger proportion of No. 1 fruit than Bor- deaux-sprayed apples, and in one of the exceptional cases the grading 192 BULLETIN No. 185 [February, of the two was equal. In the experiment at Neoga in 1911 lime-sulfur- sprayed apples graded lower than Bordeaux-sprayed apples. The results of the comparisons of Bordeaux and lime sulfur indi- cate, therefore, a greater efficiency for Bordeaux as a fungicide but, combined with its excellent fungicidal properties, serious tendencies to injure fruit and foliage as a result of its application. Lime sulfur, on the other hand, exercised a fair degree of control of fungi and caused little damage to fruit or foliage. The comparative value of the two sprays varied somewhat from year to year. In 1911 lime sul- fur caused considerable injury to fruit as a result of lime-sulfur burn, and was slightly less efficient as a fungicide than Bordeaux. In 1912 lime sulfur proved to be the most desirable spray in every series of experiments except those performed at Neoga, where it was to all in- tents and purposes equal to Bordeaux. It must be concluded from these observations that Bordeaux and lime sulfur, properly used, are both excellent sprays for the apple. Where fungous diseases are known to be serious, as in orchards which have long been neglected, the orchardist should use the stronger fungi- cide, viz., Bordeaux. Bordeaux is also advised for the cluster-bud spray, since it is a more powerful fungicide and seldom at this stage seriously injures either fruit or foliage. In orchards previously cared for the authors agree in advising the use of lime sulfur for the spray which follows the fall of the petals, and for the third summer spray, which follows from a week to ten days after the fall of the petals. 3. Can Bordeaux injury be lessened or prevented by frequent sprayings with the same spray or by maintaining over the Bordeaux a coating of lime thruout tine, season? Experiments were made to test this point at Neoga in 1910 and 1911, and at Centralia and Griggsville in 1911. The results of the ex- periments at Neoga in 1910 (page 71) indicated that "injuries to foli- age and fruit following the use of Bordeaux were lessened by following the applications of Bordeaux as soon as dry with 8/100 milk of lime. ' ' It was further noted that "applications of milk of lime had a stimu- lating effect upon the foliage." The results at Neoga in 1911 (page 87) indicated that "injuries to foliage and fruit following the use of Bor- deaux were lessened (1) by following the applications of Bordeaux as soon as dry with 8/100 milk of lime, and (2) by using the drench spray of Bordeaux." At Centralia in 1911 (Table 28, page 135) Plats J and K, where the regular applications of Bordeaux were followed immediately by sec- ond or sealing-in applications of Bordeaux and milk of lime respec- tively, showed no better control of scab and no less injury to the fruit than some of the plats which were not sprayed with the follow-up ap- plications. Foliage injury was more severe in Plats J and K than in the other plats. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 193 The experiments at Griggsville in 1911 indicated (pages 164-165) that second applications of Bordeaux following immediately after the three regular applications did not affect in any way the amount of rus- set on the fruit. Applications of milk of lime even appeared to increase rather than reduce the amount of russeting. Bordeaux injury did not appear on the foliage until late in September. Plats receiving the fol- low-up sprays were as severely affected as those which received only the regular applications. The foliage on all the Bordeaux-sprayed plats fell slightly prematurely and at the same time. As none of the secondary sprays gave extremely marked results, even tho they showed some beneficial effects in certain of the experi- ments, it is concluded that secondary applications of neither Bor- deaux nor milk of lime can be recommended other than in an experi- mental way. 4. Is it possible to interchange Bordeaux and lime sulfur, in a spray schedule, to advantage, using Bordeaux for one or more appli- cations and lime sulfur for the remaining applications ? The results of these experiments in general indicate that Bordeaux is a more powerful fungicide than lime sulfur but that it frequently causes such serious damage to fruit and foliage that its use is not al- ways satisfactory. Theoretically, therefore, it seemed possible that Bordeaux might be used for the spray before the bloom, when there was little possibility of injuring the small, still unfertilized apples, and when the foliage was so little unfolded as to expose very little sur- face to its action, as in most seasons this spray is the most effective one in combating apple scab. This spray might then be followed by lime sulfur or Bordeaux, as circumstances might indicate, for later applica- tions, thus avoiding the leaf injury and fruit russeting which accom- pany the later, particularly the second, applications of Bordeaux. Ex- periments were accordingly planned to compare all possible combina- tions of Bordeaux and lime sulfur for the first three applications, and were carried out at Centralia and Griggsville in 1911, and at Neoga, Flora, and Griggsville in 1912. The experiments at Centralia in 1911 showed that in the control of scab "The differences" between the sprayed plats, "tho small, con- sistently favored Bordeaux for the first spray." L. E. Foglesong, in charge of these experiments, reports, "In the season of 1911, the first spray (applied before the blossoms opened) was clearly the important one in the control of scab." (Page 134.) At Griggsville in 1911 (Table 44, page 166), Plat H, which received Bordeaux for the first application and lime sulfur for the second and third applications, gave the largest proportion of No. 1 apples. Plats sprayed more frequently and later with Bordeaux showed a better con- trol of sooty blotch and flyspeck, but the fruit on these plats was much more russeted than on Plat H. 194 BULLETIN No. 185 [February, The Neoga experiments of 1912 indicated (page 103) that "the most satisfactory treatment consisted of Bordeaux arsenate of lead for the first application, and lime sulfur arsenate of lead for the second and third applications. ' ' At Flora in 1912 the use of lime sulfur for the first three applica- tions gave better results than any of the combination sprays, but Bor- deaux for the first application with lime sulfur for the second and third ranks second in desirability. The relative amounts of injury to the fruit caused by Bordeaux at the various applications is presented in Table 22, page 114, and shows that comparatively little was due to the first application. The Griggsville experiments in 1912, like those at Flora, favored spraying for the first three applications with lime sulfur alone, but with unsatisfactory results from Bordeaux at the first application with lime sulfur for later applications, Table 48, page 180. A. J. Gunderson, in charge of the experiments at Griggsville, re- ports (page 179) as follows, "The more seldom Bordeaux was used and the more often lime sulfur was used, the better the color, finish, and smoothness of the fruit." Fruit receiving Bordeaux was more se- verely russeted than fruit sprayed with lime sulfur, more russet occur- ring at the first application than from the later sprays in these experi- ments. Foliage injury occurred in all Bordeaux-sprayed plats. Plats sprayed but once with Bordeaux made a good recovery, but plats sprayed more than once failed to recover during the remainder of the season. The general conclusions from these experiments are that the use of Bordeaux for the spray before the blossoms open is generally advis- able and that lime sulfur should be used for the second and third sum- mer sprays. 5. What is the most effective and at the same time the most eco- nomical dilution of lime sulfur as a fungicide spray? In various experiments lime sulfur has been used at dilutions run- ning from 3i/£ pounds of sulfur in 100 gallons of spray mixture (1 gal- lon commercial concentrated lime sulfur testing 33° Baume in 80 gal- lons of spray mixture) to 13% pounds of sulfur in 100 gallons of spray mixture (1 gallon commercial concentrated lime sulfur, testing 33° Baume, in 20 gallons of spray mixture). As will be seen from Table 55, the results were somewhat variable. Taking into considera- tion, however, not only the plats designed particularly to answer this question, but also all results from plats sprayed with lime sulfur, it has been found that lime-sulfur sprays containing from 6 to 8 pounds of sulfur in each 100 gallons of spray mixture give eminently satisfac- tory results. Sprays of these strengths are obtained by using 1 gallon of commercial concentrated lime sulfur in from 33 to 40 gallons of water, or 1 gallon of homemade lime sulfur prepared according to the Illinois formula in 18 to 24 gallons of water. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 195 TABLE 55. — EFFECTS OF VARYING DILUTIONS OP LIME SULFUR FOR SUMMER SPRAYS | 3 Dilutions of lime sulfur Place Year 1 c Pagt Compared with lime sulfur, 1 gal. to 40 of As regards used 9 water (com.) K 1 to 50 (com.) Neoga '11 O.S.W. 81 Superior Scab 1 to 20 Inferior Scab 1 to 80 (com.) Neoga 'IS O.S.W. 100 Inferior Scab 1 to 60 (com.) Inferior Scab 1 to 20 (com.J Inferior Scab 1 to 36 (111. Griggsville '12 A.J.G. 184 Superior Scab form.) 1 to 18 Inferior Scab 1 to 18 Superior Scab 1 to 14 Superior Scab 1-33, 1-63 (com.) Anna '12 L.E.F. 149 Equal All results 1-53 6. Is homemade concentrated lime sulfur, prepared according to to the formula: 100 pounds sulfur, 50 pounds lime, 50 gallons water, as efficient as the ordinary commercial concentrated lime sulfur f Experiments were conducted to test this point in 1910 at Neoga and Centralia, with results, as will be seen from Table 56, slightly favoring the commercial article. In 1911 and 1912 the formula above mentioned was abandoned in favor of the Illinois formula, 100 pounds sulfur, 50 pounds lime, 66 gallons water. TABLE 56. — EFFECTS OF HOMEMADE CONCENTRATED LIME SULFUR Year Place Experimenter Page Homemade concentrated lime sulfur compared with For control of Bordeaux Commercial concentrated '10 '10 Neoga Centralia O.S.W. L.E.F. 61-64 128 Inferior Inferior Superior Inferior Equal Slightly superior Equal Inferior Inferior Scab on foliage Scab on fruit Foliage injury Foliage injury Scab 7. What is the fungicidal value of self-boiled lime sulfur, and how does it compare with lime sulfur made in the usual manner? Self-boiled lime sulfur was experimented with at Griggsville in 1909 and at Neoga in 1910. Table 57 presented herewith shows at a glance that this spray proved inferior to lime sulfur made in the usual way, and also inferior to Bordeaux where self -boiled lime sulfur 196 BULLETIN No. 185 [February, and Bordeaux were compared. Reference to the reports of experi- ments for the years 1909 and 1910 shows that the experimenters found self -boiled lime sulfur practically worthless as a fungicide for both the fruit and foliage of the apple. It appeared, however, from the reports of both series of experiments, that the self-boiled lime sulfur exerted some stimulating or beneficial effects on the health and vigor of the foliage not in any way connected with its possible properties as a fungicide. The foliage in the plats sprayed with self-boiled lime sul- fur was noteworthy for its abundance, dark green color, and generally luxuriant appearance. Its worthlessness in the control of apple scab precludes the possibility of its being used as a successful spray for the apple. TABLE 57. — EFFECTS OF SELF-BOILED LIME SULFUB Year Place Experimenter Page Self-boiled lime sulfur compared with For control of Bordeaux Lime sulfur '09 '10 Griggsville Neoga L.E.F. O.S.W. 121 122 61-62 62-63 Inferior Inferior Inferior Inferior Inferior Scab on fruit Scab on foliage Scab on foliage Scab on fruit 8. Will the addition of copper sulfate to lime nulfur increase the fungicidal value of the spray? In an effort to increase the fungicidal properties of lime sulfur, cop- per-sulfate solution was added to this spray and tested in 1911 at Neoga, Centralia, and Griggsville, and in 1912 at Flora. The ex- periments at Neoga (page 87) showed that "lime sulfur arsenate of lead in combination with copper sulfate gave an efficient spray and caused no injury to either fruit or foliage." The experiments at Centralia (pages 134 and 137), showed that the addition of copper sul- fate in considerable quantities (8 pounds in 100 gallons) resulted in a marked reduction in the amount of sooty blotch, but that it was not more efficient than lime sulfur alone in the control of other diseases. Moreover, it resulted in more severe russeting of the fruit than lime sulfur alone in the experiments at Griggsville, reported on page 170. The addition of copper sulfate failed to produce any marked increase in the fungicidal properties of the spray, and it resulted in more rus- seting of the fruit, the amount of russeting increasing with the amount of copper sulfate added. At Flora in 1912 copper sulfate was added to lime sulfur only for the application of spray made before the bloom. The application was no more efficacious than that of lime sulfur alone in the control of scab. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 197 and it resulted in an unusually severe russeting of the fruit (page 116). It is concluded, therefore, that the addition of copper sulfate to lime sulfur does not add to its usefulness as a spray. In three of the experiments reported on, it resulted in more or less severe injury to Ihe fruit. 9. Is an application of lime sulfur made at the strength used for San Jose scale, applied while the trees are dormant, of any value as a preventive of apple scab ? Experiments were made bearing upon this point at Centralia and Griggsville in 1911, and at Neoga in 1912. The results of the experi- ments at Centralia (page 137) indicate that "there is no evidence to show that the dormant-tree application exerted any influence in check- ing the development of scab." Experiments at Griggsville bore out those at Centralia. On page 161 it is stated that Table 41 shows that "the dormant-tree application of lime sulfur had no effect on apple scab." The experiments on this point at Neoga in 1912, reported in Table 13, page 91, indicate that a winter application is of doubtful benefit. The average infection of scab in the. winter-sprayed plats amounted to 22 percent as compared with an average infection of 25 percent on those which did not receive the winter application. In all of the experiments reported, the winter applications were followed later by the regular summer sprays. The authors are, there- fore, of the opinion that it is possible, in spite of the results presented, that winter applications might have exercised some degree of control over scab which could not be detected in comparison with other plats, owing to the fact that they received all the sprays that were absolutely necessary for the control of this disease. To test this point it would be necessary to give only a winter application which should not later be followed by the regular summer sprays. As the regular summer sprays could not, of course, be abandoned, the results of the experi- ment bearing on this point lead to the inevitable conclusion that the dormant-tree spray with lime sulfur is unnecessary for the control of the apple scab. 10. What is the most effective poison which can be combined ad- vantageously with standard fungicides for the control of chewing in- sects, particularly the codling moth and the plum curculio? Paris green and arsenate of lead were the only insecticides experi- mented with. These were compared in plats at Griggsville in 1909, and the results are tabulated in Table 26, page 124. Paris green proved less effective than arsenate of lead and caused considerable foliage in- jury. When used separately, as in Group 1 of the Griggsville experi- ments in 1909, Paris green and arsenate of lead gave practically equal control of codling moth, tho arsenate of lead proved superior in pre- venting injury from curculio. Paris green caused very serious foliage injury in Plats 8 and 10, and considerable injury in Plat 9. 198 BULLETIN No. 185 [February, As these results confirmed previous experiments and more or less universal experience, further tests with Paris green were considered unnecessary and experiments with this insecticide were accordingly abandoned. When experiments with copper ferrocyanide were commenced, it was thought that this spray might possess some poisoning qualities which would make it useful as an insecticide. It was not, of course, used in combination with Bordeaux or lime sulfur, as the spray was designed as a fungicide. It may be noted, however, that copper ferro- cyanide failed to show any decided qualities as a poison spray. 11. Does arsenate of lead when used alone possess any fungicidal value f Experiments bearing upon this point are reported from Neoga in both 1911 and 1912, and from Griggsville in 1911. The first of these experiments in 1911 at Neoga appeared to show that arsenate of lead when used alone did exercise some fungicidal action, but was respon- sible for considerable foliage injury (page 87). The experiments of 1912, however, lead to the following conclusion (page 103) : "Arsenate of lead alone possesses practically no fungicidal value and should never be used except in combination with a fungicide. ' ' The Griggs- ville experiments for 1911 reported on page 171 confirm these results (arsenate of lead had practically no fungicidal value). 12. Does arsenate of lead when added to Bordeaux or lime sulfur increase their fungicidal value? Experiments at Neoga in 1911 and 1912 showed (pages 87 and 103) that a mixture of lime sulfur and arsenate of lead was more efficient in preventing apple scab than lime sulfur used alone. In fact, in 1912 O. S. Watkins reports : ' ' Lime sulfur arsenate of lead is a very much more efficient fungicide than lime sulfur alone. ' ' The experiments at Anna in 1912 (page 150) indicated that "the neutral and mixed arsenates of lead did not add to the effectiveness of lime sulfur in the control of scab. ' ' Acid arsenate of lead added to lime sulfur appeared to improve the fungicidal value of the spray for the control of this disease. The addition of all kinds of arsenate of lead to lime sulfur gave a spray superior to lime sulfur alone for the control of sooty blotch. At Griggsville in 1912 (page 186) "lime sulfur arsenate of lead was slightly more effective in controlling scab, flyspeck, and sooty blotch than lime sulfur alone. ' ' Thruout the experiments in general, the addition of arsenate of lead to Bordeaux added nothing to its fungicidal value. It is concluded, therefore, that the addition of arsenate of lead to lime sulfur increases its fungicidal value, while the addition of arsen- ate of lead to Bordeaux does not improve the fungicidal value of the resulting spray. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 199 13. Are there differences between various brands of arsenate of lead which would make one brand more useful than another, either alone, or in combination with the standard fungicides ? Various brands of arsenate of lead have been used alone or in com- bination with standard fungicides at Neoga and Centralia in 1910, at Neoga in 1911, and at Anna in 1912. The experiments at Neoga in 1910 (page 71) indicated that "for use with lime-sulfur solution, neutral or ortho arsenate of lead gave better results than arsenates of lead containing higher percentages of arsenic oxid. ' ' No results were obtainable at Centralia in 1910. In 1911 the experiments at Neoga showed rather insignificant dif- ferences between the various brands of arsenate of lead, but 0. S. Watkins, in charge of these experiments, states that ' ' altho the results recorded in the different columns do not show wide variation between the different plats, they are in accord with those obtained in 1910, which showed that, in combination with lime-sulfur solution, the neu- tral arsenate of lead produced a spray which was more efficient and safer to use than those arsenates of lead higher in arsenic oxid. ' ' At Anna in 1912 (pages 150 and 152) acid arsenate of lead used with lime sulfur showed a small but consistent lessening in the amount of scab and sooty blotch over mixed and neutral brands. All brands effectively controlled codling moth, but inconsistent differences appeared in the control of curculio. The various classes of arsenate of lead when used in combination with Bordeaux showed no important differences in the control of diseases, insects, or injuries to the fruit. It was found that arsenates of lead were more efficient used in combination with the fungicides than alone, and that they caused less foliage injury. 14. Of what value are certain new sprays both as fungicides and as insecticidesf Among the new sprays experimented with were copper ferrocyan- ide, Cucasa, and Sulfocide. Of these, Sulfocide proved unsatisfactory, as, when used in combination with Paris green, it severely injured the foliage (report of spraying experiments at Neoga, in 1911, 0. S. Watkins, page 87). Cucasa proved almost as efficient as Bordeaux, caused no russeting of the fruit, but was somewhat injurious to foli- age (page 87). Not being more efficient than Bordeaux, this spray was also abandoned. Copper ferrocyanide made by combining copper sulfate and potas- sium cyanide seemed to possess advantages, both from the theoretical and practical standpoint, that made it seem advisable to test this spray somewhat more thoroly. Experiments were accordingly conducted with copper ferrocyanide at Neoga in 1911, and at Anna, Flora, and Griggsville in 1912. Table 58 presents a summary of results from the use of this spray. 200 BULLETIN No. 185 [February, be 'o 3 q_l o a be P rO^S «H 73 O „ a rt | be r* r-t -— -~ n a ;__;_;_ m ||| i| 8 .2 o o o o •r"i "r"1 *r^ "r^ ffl 1 An 00 00 1 1 r-l rH r-l iH OO 00 fin 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 201 In 1911 copper ferrocyanide proved superior to Bordeaux and lime sulfur with regard to the vigor of the foliage, and superior to Bor- deaux with regard to the grading of the fruit. It was inferior to Bor- deaux in the control of scab on the fruit. At Flora in 1912 it again proved superior to both Bordeaux and lime sulfur with regard to vigor and abundance of foliage, and it also caused less foliage injury. It was equal to Bordeaux and lime sulfur in the control of scab on the fruit, but inferior in the control of blotch, sooty blotch, and flyspeck. It caused less russet than Bordeaux, but more than lime sulfur. In the experiments at Anna it proved inferior in the control of scab, sooty blotch, and flyspeck to both Bordeaux and lime sulfur. It caused less russeting of the fruit than Bordeaux, but more than lime sulfur. The most discouraging results from this spray are reported from Griggs- ville, where it was tried on several plats and at various strengths, both in combination with an insecticide and separately. In this entire series of experiments copper ferrocyanide appeared to be worthless. It is believed by the authors of this bulletin that this spray is worthy of further investigation, but the results thus far obtained do not warrant recommending copper ferrocyanide other than in an ex- perimental way. 15. How often and at what times should summer sprays ~be ap- plied f Experiments bearing directly on these points were performed at Griggsville in 1909, at Neoga and Griggsville in 1911, and at Neoga and Anna in 1912. The results at Griggsville in 1909 emphasized the importance of the spray applied immediately after the fall of the petals. The spray applied at this time reduced codling-moth injury from 17 percent on the unsprayed plat to 3 percent on the sprayed plat; it reduced scab from 89 percent on the check to 49 percent on the sprayed plat. Altho there was less injury from codling moth in the plat sprayed once before the bloom than in the check plat, the difference could scarcely be due to the effect of the spray, and this spray apparently reduced scab from 89 to 85 percent only. (See Table 25, page 123.) In 1911, at Neoga, plats were sprayed three, four, and five times. The fourth application of homemade lime sulfur reduced scab from 51 to 44 percent, and the fifth application further reduced it to 31 percent. Commercial lime sulfur reduced scab from 39 to 28 percent at the fourth application, but no further reduction appeared to fol- low the fifth application. The fourth application of Bordeaux did not seem to reduce scab, but a fifth application reduced scab from 25 to 15 percent (Table 6, page 76). The irregular character of these re- sults is probably traceable to the different sticking qualities of the fungicides. Bordeaux from the early sprays remained on the trees long enough to make a fourth application unnecessary. The fifth ap- plication, however, was made at a time when the coating of Bordeaux was disappearing and in time to lessen damage from a comparatively late attack of scab. 202 BULLETIN No. 185 [February, The experiments at Griggsville in 1911 (Table 43, page 166) gave the following results: The addition of three extra summer sprays (six in all) resulted in a slightly better control of curculio, but did not in- crease the production of No. 1 apples to any considerable extent. Scab, sooty blotch, and flyspeck were almost perfectly controlled by the first three sprays: it appeared, therefore, that the additional applications were unnecessary in 1911. The Neoga experiments in 1912 (Table 14, page 93) indicated, ' ' The use of more than three applications seemed unnecessary in 1912, as the variation between the percentages of No. 1 apples in the differ- ent plats is neither regular enough nor varied enough to permit draw- ing definite conclusions." In the experiments at Anna in 1912 (Table 31, page 146) the first application reduced codling moth slightly, the check plat showing 30 percent and the sprayed plats 18 and 24 percent respectively for lime sulfur arsenate of lead and Bordeaux arsenate of lead. Curculio were unaffected by the first application. Scab was reduced from 83 to 63 and 69 percent respectively in the lime-sulfur and Bordeaux-sprayed plats. The second application resulted in the reduction of codling- moth injury from 18 to 11 percent in the lime sulfur arsenate of lead plat, and from 24 to 17 percent in the Bordeaux arsenate of lead plat. Curculio were again unaffected by this spray. Scab was not affected by lime sulfur at this application, but Bordeaux showed a reduction from 83 to 63 percent. The third application alone was slightly less effective in controlling the codling moth than the second, and slightly more effective than the first. Its effects on curculio and scab were negligible. The omission of the first spray proved serious in the control of scab, and the omission of the second spray was equally unfavorable in the case of the codling moth. In this series of experiments the omission of the third spray where Bordeaux was used for the first and second sprays did not prove serious, but the omission of the third applica- tion where lime sulfur was used for the first two sprays was found inadvisable. The addition of a fourth spray reduced injury from codling moth, curculio, and sooty blotch, but did not affect scab. Five applications further reduced curculio injury but did not affect codling moth, apple scab, or sooty blotch. In general, it was found that thq first three summer sprays were the: most useful in improving the general grade and quality of the fruit by controlling the majority of the insects and fungi ; that none of these sprays could be omitted safely; and that the addition of the fourth and fifth sprays assisted in controlling late-brood codling moth and injury from curculio. 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 203 16. What are the relative advantages and disadvantages of apply- ing large and small quantities of Bordeaux? Experiments bearing upon this question were performed both at Griggsville in 1911 and at Anna in 1912. The first of these (pages 163 and 164) indicated that light and heavy sprayings were equally effec- tive in the control of apple scab ; that heavy applications controlled sooty blotch and flyspeck fungi and codling moth and curculio more efficiently than the light applications. Fruit receiving the heavy appli- cations, however, was poorer in color and more severely russeted than fruit receiving the light applications. These latter differences about counterbalanced the former advantages, the grading from the two be- ing practically equal. . In the experiments at Anna in 1912 (page 150), heavy applications of Bordeaux arsenate of lead were more efficient as a protection against curculio and scab than lighter applications, equally efficient in the control of sooty blotch, and equally inefficient in the control of codling moth, but they resulted in more russeting of the fruit than the light applications. On the whole, these experiments indicate that a thin but complete- coating of the fruit and foliage with Bordeaux arsenate of lead is more desirable than a heavy coat, except in cases where special protection from curculio is necessary. INCIDENTAL OBSERVATIONS Included under this heading are various observations which can- not readily be tabulated, and which were incidental to the principal lines of inquiry. They are put together under this heading for con- venient reference. 1. Owing to the danger of russeting the fruit as a result of appli- cations of Bordeaux, it is a more or less common practice to omit the fungicide from the spray following the fall of the petals, as this spray is applied more particularly for the control of codling moth. It has, however, been found inadvisable to omit the fungicide, as an infection of scab is very likely to occur at this time. 2. In several experiments lime sulfur appeared to attract codling moth and to repel curculio. The former effect was more marked than the latter, but both facts were observed with a considerable degree of consistency thruout the progress of the experiments. 3. Various quantities of arsenate of lead were used in an attempt to find the most efficient killing spray. Four pounds of paste arsenate of lead in 100 gallons of spray mixture was found efficient and econom- ical. 4. Adding the sludge, which remained after the preparation of concentrated lime sulfur, to the spray mixture did not improve or im- pair the efficiency of the spray. 204 BULLETIN No. 185 [February, Recommendations As a result of the spraying experiments detailed in this bulletin, and also from other experience and recommendations, the authors rec- ommend that apple trees be sprayed at the times and in the manner indicated below. 1. Dormant-tree spray. — This spray is used particularly for the control of San Jose scale. It is applied in the fall after the leaves drop or in the spring before the buds open, preferably at the latter time. Where San Jose scale is present or is known to infest a certain locality, this spray is a necessity, and it is advised as a matter of pre- caution in all orchards thruout the state. The dormant-tree spray should be either commercial or homemade lime sulfur. The commercial lime sulfur testing 33° Baume should be used at the rate of 11 gallons of commercial lime sulfur to 89 gal- lons of water, or 11 gallons of commercial lime sulfur in 100 gallons of the spray. This is equivalent to 1 gallon of commercial lime sulfur to 8 gallons water. The homemade lime sulfur, made according to the Illinois formula, described on page 54, is used at the rate of 20 gal- lons of stock solution homemade lime sulfur to 80 gallons of water, or 20 gallons of homemade lime sulfur in 100 gallons of spray. 2. First summer application. — This spray is used particularly for the control of apple scab. As a secondary object, however, it is used to kill the various leaf -eating insects which appear early in the season, including bud moth, tent caterpillar, and canker worm. These insects, tho not always present in large numbers, are likely to cause serious damage and must be guarded against. The first summer application is made after the cluster buds open, as soon as the individual flower buds spread apart, but before the flower buds themselves open. In large commercial orchards it will be found necessary to begin spraying before all the individual flower buds have spread apart, in order to complete spraying before the first blossoms open. Spraying may be continued at this time until the petals have commenced to separate, but should be discontinued as soon as the stamens and pistils of the flowers are exposed. Bordeaux, prepared according to the formula, 8 pounds copper sulfate, 8 pounds freshly slaked lump lime, and 100 gallons of water, with 4 pounds arsenate of lead added as an insecticide, is the best spray for use at this time. The preparation of this spray is described on page 54. 3. Second summer application. — This spray is used particularly for' the control of the codling moth, but is of almost equal importance as a preventive of apple scab. Incidentally, it is advantageous as a protection against various leaf-eating insects. It is applied immediately after the fall of the petals, while the lobes of the calyx are still distended. The greater number of the first brood 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 205 of the codling moth enter the apple thru the calyx end. By spraying the trees while the calyx cups are still open, poison will be placed on the base of the lobes and stamens and sometimes within the cup itself, where the larvae of the codling moth are reasonably sure to get it when entering the apple. At this stage the small apples point upward or outward, and the calyxes are easily coated with poison. For this application lime sulfur arsenate of lead, using 2i/^ gallons of commercial concentrated lime sulfur, or 5 gallons of homemade lime sulfur (Illinois formula, page 54) in 100 gallons of spray, is recom- mended. 4. Third summer application. — This is used as an additional pre- caution against apple scab and codling moth. It is also a safeguard against leaf-eating insects, and to some extent against certain fungous diseases which appear later in the season, including blotch, sooty blotch, flyspeck, and leaf spot (SpTiaeropsis malorum). This spray should be made about ten days after the second sum- mer application. In large orchards the second spray would in all prob- ability not be completed at one end of the orchard until it was time to commence the third summer application at the other. The best spray for this application appears to be lime sulfur arsenate of lead. 5. Fourth summer application. — This spray is applied as a safe- guard against apple blotch and codling moth. It is applied two to three weeks after the third summer spray. Bordeaux arsenate of lead should be used in hot dry weather ; lime sulfur arsenate of lead should be used in cool weather. 6. Fifth summer application. — This spray is particularly for the control of the second brood of codling moth, and incidentally for the prevention of curculio injury, blotch, sooty blotch, flyspeck, and leaf spot. It is made approximately ten weeks after the bloom, or at times varying from the last week in June in the extreme southern part of Illinois to August 1 in the northern part of the state. For this spray arsenate of lead and lime should be used. Where fungous injury is anticipated, Bordeaux arsenate of lead may be sub- stituted. *{ 7. Extra sprays. — Extra sprays are chiefly used as safeguards against bitter rot. Where this disease is anticipated, spraying should begin the last week in June, and should be followed at intervals of ten days until four applications have been made. Bordeaux is the proper fungicide to use for this disease. It is prepared in the same manner as for the first summer application. If no preventive measures have been taken against bitter rot, and the disease appears suddenly and unexpectedly, spraying should be commenced without a moment's de- lay as soon as the presence of the disease is discovered. 206 BULLETIN No. 185 [February, o o g o w OQ 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 207 PLATE 2. — BURN DUE TO SPRAYING WITH LIME SULFUR DURING VERY HOT WEATHER 208 BULLETIN No. 185 [February, PLATE 3. — UNSPRAYED TREES, OCTOBER 2, 1912; ADJOINING TREES SHOWN IN PLATE 4 PLATE 4. — SPRAYED TREES, OCTOBER 2, 1912; ADJOINING TREES SHOWN IN PLATE 3 THE PICTURES IN PLATES 3 AND 4 WERE TAKEN FROM THE SAME SPOT 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 209 PLATE 5. — GRIGGSVILLE EXPERIMENTS, 1912 A. TREE SPRAYED WITH BORDEAUX B. TREE SPRAYED WITH LIME SULFUR PLATE 6. — GRIGGSVILLE EXPERIMENTS, 1912 A. APPLES SPRAYED WITH BORDEAUX B. APPLES SPRAYED WITH LIME SULFUR 210 BULLETIN No. 185 [February, PLATE 7a. — GRIGGSVILLE EXPERIMENTS, 1912 APPLES SPRAYED WITH LIME SULFUR PLATE 7b. — GRIGGSVILLE EXPERIMENTS, 1912 APPLES SPRAYED WITH BORDEAUX 1916] FIELD EXPERIMENTS IN SPRAYING APPLE ORCHARDS 211 PLATE 8. — BLOSSOM BUDS EEADY FOR APPLICATION OF FIRST SPRAY 212 BULLETIN No. 185 [February, PLATE 9. — THE PROPER CONDITION AND TIME FOR THE SECOND SUMMER SPRAT; THE CALYX CUPS ARE STILL OPEN AND THE FRUITS POINT UPWARD AND OUTWARD PLATE 10. — THE PROPER CONDITION AND TIME FOR THE THIRD SUMMER SPRAY UNIVERSITY OF ILLINOIS-URBANA