T «Inlxlmllllll W m T“ T \ ““U H T H“ -—'|U'|._\ Iow _(DCDO THE INFLUENCE OF CERTAIN SPRAY MATERIALS ON THE SIZE OF FRUIT TN THE SOUR CHERRY ' "a T n 1 esis for Degree of M. 5. Howard M. W’eUs I 9 3 5 T30 50%? THS LIBRARY Michigan State Un‘ ‘ PLACE IN RETURN BOX to remove this checkout from your record. TO AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 5/08 Kthroleoc8PrelelRClDaIeDue indd The Influence of Certain Spray Materials on the k-_ Size of Fruit in the Sour Cherry THESIS Submitted to the Faculty of the Michigan State. College of Agriculture and Applied dcience in partial fulfillment of the require- ments for the degree of Master of Science. By Howard M. Walla June 1925 THESIS Introduction Perhaps the most striking difference be- tween orcharding of the present and that of a generation ago lies in the control of insect and fungous pests which has develooed in this period. Hen still actively engaged in fruit growing were growing fruit when spraying in the orchard was becoming established and have seen the transi- tion from the use of Paris green applied in a haphazard way/with a bucket or barrel pump, to the use of a gasoline- driven sprayer aoplying a number of :omplex materials according to an elaborate time schedule. It is but inev- itable and proaer that in this rapid series of changes the 'chief thought has been the destruction of the pests, with little attention to the plants themselves, so long as they would survive the treatment. With the more pressing questions of pest control met, growers and investigators have been able recently to turn their attention more closely to the effects of Spray materials on the plants which they were used to protect. That such effects exist and that they are in some cases harmful, in some cases beneficial, has been recognized. In fact, there has accumulated a considerable volume of data on what may be termed spray injury, the term being used to refer parti- cularly to those forms of foliage and fruit injury generally classed as burning, yellowing and russeting. Less infbrmation is available cancerning other more or 104'; ’73; - 2 - less direct influences of Spray materials that are known to assume considerable importance at times. Recent investigations by the Michigan Agricultura Experiment Station on the control of cherry leaf spot (1) have called attention to a more or less serious dwarfing of the fruit resulting from the use of certain spray applications. The problem thus raised has seemed of sufficient importance to warrant a study of the situation. This paper presents a resume of some of the more important investigations that throw light on the matter, together with a detailed account of some experi- ments that deal more directly with it. Literature Reviewed Iany reports have been made regarding the influence of apray materials on some of the more important physiological responses of plants. Of the studies made practically all have had to do with bordeaux mixture made according to various formulae. Lodeman (2) and Harrison (3) reported that plum, beach and pear leaves were thicker when Sprayed with bordeaux mixture than when left unsprayed. Zucker (4), working with a number of greenhouse plants, found that Spraying with bordeaux mixture increased the chlor0phyll content of the leaves in most cases, while starch formation and transpiration were increased in all cases. (N Ruth (5), published data to show that spraying primodial leaves of bean with bordeaux mixture resulted in an increased chlorophyll content per unit area and per unit fresh weight, though there was an atten- dant decrease in the leaf area develOped. Chuard and Porchet (6) state that Spraying with bordeaux mixture increased the sugar con- tent of mature fruits of currants and gooseberries, at the same time lengthening the growing season of the plant as measured by date of leaf fall. By injecting small quan- tities of COpper salts into the plant they were able to hasten the maturity of the fruit. However, larger quantities proved toxic to the plant. Ewert (7) found that potato leaves which had been sprayed with bordeaux mixture contained more starch than those on unsprayed plants. Upon subjecting the enzyme diastase to the action of a very slight trace of cogper he found that it would not act upon starch. Ewert attributes the presence of starch in the Sprayed leaf to the action of traces of copper on the enzyme diastase within the leaf and to represent a retarding of conduction rather than an increase in manufacture. Among the earlier reports on the physiological effects of bordeaux Spraying was that made by Rumm (8),who found that grapes Sprayed with bordeaux mixture flowered earlier and also ripened their fruit earlier than those left unsprayed. In 1912 Ewert (9) published a paper on the effect of spraying with alkaline bordeaux mixtures. among the plants used in his experiments were currants and gooseberries. White currants Sprayed with one per cent and those Sprayed with four per cent. bordeaux mixtures produced sweeter fruits than unsprayed plints. Those sprayed with the one per cent. mixture gave the highest yield. In another eXperiment, spraying once a week throughout the season increased the sugar content of the fruit but decreased the yield as measured by weight of the berries. He reports that Spraying the fruit only with a one per cent. bordeaux mixture resulted in a higher sugar content than was found in the berries either on unSprayed plants or on those having both foliage and fruit Sprayed. Vhile conducting brown rot investiga- tions witd sweet cherries Fisher (10) noticed that some of the sprays used produced a reduction in the size of the cherries. In one orchard the reduction was so great that the fruit could not be marketed profitably. The data collected by Fisher are presented in Table 1. Table 1. -- Average number of sweet cherries per pound 1917. Treatment Variety Royal Ann Black Republican Self boiled 1i e-sulphur 127 177 8-8-50 Bordeaux mixture 2-4-50 128 233 Comnercial lime-Sulphur 1-50 111 126 CheckL unsprayed 92 101 The influence of the spray materials used on the size of fruit in the fioyal nnne cherry was not great. However, in the Black Republican, a variety ripening from one week to ten days later, the differences in Size were more distinct. In 1918 Fisher attemyted to determine what factor was responsible for the reduced size of the fruit. In this test a number of sprays with various degrees of alkalinity were used together with a number of Spreaders and other materials. He concluded that any alkaline spray had a tendency to reiuce the size of the fruit. It was suggested that this influence was produced through the action of the Spray material in destroying the bloom on the fruit, thereby increasing evaporation. Frank a Kruger (11) observed that spray- .4. ng potatoes with bordeaux mixture stimulated various physiological activities of the Sprayed plants. The chlorOphyll content of the leaf was increased, as was its length.of life. ‘Increasing the chlorOphyll content was thought to be indirectly responsible for greater starch formation and storage in the tubers. The rate of trans- piration was found to be accelerated when bordeaux mixture was applied. Diggar and Cooley (12) reported potato plants sprayed with bordeaux mixture to transpire more water than plants Spsayed with lime-sulphur, or left unsprayed. A11 Sprays used that produce surface films were found to increase the amount of water tranSpired. at the same time the increased water loss resulting from the use of dusts was very slight. The exact manner in which the films act to increase transpiration was not de- finitely determined. However, Duggar and Bonns (15) were of the Opinion that the film produced when plants are Sprayed acts as a spongy material, taking water directly from the interior of the leaf through some con- tinuous water channel to the coating of spray material on the leaf surface where the evaporating area would be greatly increased. Experiments with potato, tomato, Marguerite and tobacco, showed that spraying with bordeaix mixture increased the rate of tranSpiration chiefly during the night. Castor bean leaves when sprayed tranSpired more during both the day and night than unsprayed leaves. .The period of greitest water loss was the one immediately following spraying. The work of Duggar and Cooley was later confirmed by Martin (14), who used a number of abscissed leaves of plants growing in the greenhouse. Spraying with bordeaux mixture was found to increase transpiration with all plants used except cabbage. Butler (15) states that the effect of bordeaux on plants is one of shading; that the physiological responses produced depends on the epagueness of the spray used. When potato, tomato, Russian sunflower, and Coleus were used in tranSpiration tests, as measured by the rate of transpiration for the periods before and after spraying, the water loss was increased by spraying, the greatest increase in transpiration occurring during the night. When the lower surface of Russian sun- flower leaves was sprayed the rate of transpiration was affected in the same direction as when the upper surface was Sprayed. By means of standardized cobalt chloride paper Shrieve and Martin (16) measured the rate of trans- piration from tomato plants in the field. One-half of each plant was sprayed with bordeaux; the remainder was left unsPrayed as a control. In all cases the rate of tranSpiration was found to be greatest from the parts of the plant that had been sprayed. It is also to be noted that this increase Was found to occur during the day and the 24-hour period following the application of the spray mat erial. The literature cited reveals some of the More definite physiological responses occurring when plants are Sprayed with bordeaux mixture. That spraying with bordeaux mixture increases chlorOphyll development. Starch and sugar :ormation and transpiration are now re- cognized as definite facts. In one case, data have been presented which show certain reductions in the size of cherries resulting from the sprays used. There is, however, little available information regarding the --ei tion establish 4 .L'fi. 1 9 f ‘a 00:38 9 an? erials on t + u 33 not been “ £48 ‘ c J» n‘ - -118 :8 n. q finance 0 in rowt E g. .l S r! .1. 'ne I - i 3 i .4 - '08- n this paper cover a i d cw observation CL Ga Ga n; (J 1‘ 3 an; n A n A ' I 0 v 13 located were i e ~l +v 3 "e o o- s for t v # lorello imam. I ‘r- - ‘ -u. ezpe 4—. e L. D :38 Eve '7‘" -- ..u. do I ~ , -, 1r: eaklf. “A. 'fi“ -‘ a “O .J av é Av 05 a r A. d 9v ha 2 he . ‘ .1. fig 5 w C 3 a. 9 _r9.? .5.‘., - a"' UA‘ J3 ‘0‘- 1- .7 ‘ J S I .1 a 5 f]. f 4 C .1 A: e O 0' -5- 2.4 3 ~_.. 5 .fl. . C r; p. a: a: 3: .l .L S 1 .fi; 2. T L. .6 .3 .4; Titus orchard near Traverse City and in the Experiment Station orchard at East Lansing. Investigation at Traverse City was linited to the Kontmorency variety; that in East Lansing was with montmorency and English Horellos. The spray materials used in the Titus Brothers orchard were the same as those used in 1922 except that one additional plot was provided for spraying with Pyrox, and the sulphur dust was composed of 90$ sulphur and 10% arsenate of lead. In laying out the plots in 1925 they were arrainged so as to cross at righ angles the plots used in 1922. Three Spray materials were used in the orchard at East Lansing. One plot was sprayed with bor- deaux mixture (3-7-50). another received commercial lime— sulphur, one gallon in 40 gallons of water, while still another plot was sprayed with 7 pounds of hydrated lime to 50 rallons of water. In 1924 further Spraying and dusting investigations for the control of cherry leaf spot were donducted in a block of five year old Early Richmond cherries growing on the farm of V. R. Roach and Company at Hart. Work in this orchard permitted observations on an earlier maturing cherry and also allowed the use of additional materials for study. The COpper dust used was similar to that employed in the Traverse City orchard in 1922 and 1925. The formula for the sulphur dust was changed to 90 per cent. sulphur and 10 per cent. lead. Two plots received bordeaux xixture as follows; one was -10.. Sprayed with a 3-10-50, and the other with a 5-5-50 mixture. Another plot was Sprayed with lime-sulphur (1-40), while still another plot was treated with colloid- al sulphur at the rate of 4 pounds to 50 gallons of water. Check trees were left in the sprayed part of the orchard for comparison. Besides the work in connection with the regular eXperiments for controlling leaf spot, studies were made in a block of 100 Hontmorency cherry trees on the farm of J. C. Maynard near Grand Rapids. The purpose of the work in this orchard was to determine the relation between the quantity of spray material on the foliage and the size of the fruit. The block was divided into four plots of equal size with a sufficient number of unsprayed trees for comparison. The materials used were: bordeaux mixture (5-5-50); lime-sulphur (1-40); lime-sulphur (1-40, with the addition of 5 pounds of hydrated lime; colloidal sulphur (4-50). Schedule of Sprays Csed. -- In all or- chards where experiments were conducted the schedule of applications recommended for the control of cherry leaf spot was followed. This schedule calls for four appli- cations as follows: first, when the shucks are about one- half off the cherries; the second and third at two and four week intervals following nimber one, and the fourth application immediately following harvest. The only ex- ceptions were in 1922 when the English Morello plots were I l - 11 - dusted four times before harvest and in 1925 when the Hontmorency plots were dusted each week alternately rom opposite sides instead of the customary full application from both sides every two weeks. In the present studies, the chief interest lies in the three applications before harvest. arsenate of lead powder was used at the rate of one pound to 50 gallons of material in all applications before harvest. The dusts contained ten per- cent. by weight of arsenate of lead powder. Methods of tpplying Materials -- All Sprays were applied by means of power sprayers that main- tained a pressure of iroa 225 to 250 pounds. In all orchards,except at :Hart, the applications were made with a spray gun. at Hart a rod equipped with "Y" and disc nozzels was used. In all dusting treatments the material was applied by power dusters. a Niagara machine was used in the Titus brothers orchard, while a Dosch outfit was used at hart. Practically all dusting was done at night or at times when conditions were favorable for dusting. Yhen applications were made from both sides the foliage was well covered on both surfaces with a fine coating of dust particles. approximately one pound of sulphur dust was used per tree on the Early nichmond trees at Hart. Only three-fourths of a pound of cepper dust was re- quired to give a similar covering; The Montmorency trees - 12 - at Traverse City were larger and required more material. Rainfall -- The three years of field investigations included two seasons of heavy and one of light rainfall. Table 2. -- Total rainfall at Traverse City, from the time the first spray was applied until the cherries were harvested, during the seasons of 1922 and 1925. Year Period Rainfall 1922 May 23 to July 7. 5.81 in. 1923 June 3 to July 30 5.15 in. In Table 2 the recorded rainfall for the Traverse City section in 1922 and 1923 is given for the period extending free the time of the first application of Spray material until the fruit was harvested. The rainfall for the 1922 season was nearly double that for a similaqberiod in 1923. Since it is generally agreed that the size of fruit depends to a considerable extent on the available moisture supply during the period in which the fruit itself is developing, it is to be ex- pected that cherries would average larger in 1922 than in 1923. It sould also seem reasonable to suppose that any factor which affects size through its influence on water supply would have a greater effect of this sortjduring a dry than during a wet season. The amount of rainfall at Grand Rapids . C 'v ‘° ,' , ‘\ ’10 x in 1324 was blmllar to tnat at Traverse bity in 1922. The rainfall at Hart in 1924 was considered heavy for that section of the state. However, for nearly three weeks in June there was little precipitation. These data do not tell how much aVailable moisture there was in the soil and they do not give exact information regarding atmos- pheric humidity. However, they afford at least a crude measure of both of these factors of environment. nesults of Field Investigations. Results Secured in 1922 -- With the Opening of an early season the first spray was aoplied to the plots at Traverse City on May 23. The Montmorency crOp was harvested on July 17 and the English Morello by august 1. Because of an early infection of leaf spot no records could be secured from the unsprayed trees, since they had lost most of their foliage by the time the crop was harvested. The average sizes of cherries from the sprayed and the dusted plots for the two varieties are shown in Table 5. The difference in the sizes of the cherries from the various sprayed and dusted plots in the Hontmorency block was not great. However, the contrast between those on the cepper dusted plot and those on the plot Sprayed with 5-7-50 bordeaux mixture was sufficient to attract the attention of the casual observer. The same materials when applied to the English Korello, a variety ripening two weeks later than the Montmorency, produced more striking differences. The fruit on trees sprayed with bordeaux mixture averaged 34 per cent. - 14 - smaller than those in the plot receiving copper dust. Lime-sulphur sprayed trees produced cnerries intermediate between the two. Cherries of the two varieties on the dusted plots were practically the same in size. The smaller size of English Morello cherries on the sprayed plots mwy be accounted for in two ways. First, this variety may be nore susceptible to the dwarfing effect of the spray material. A second and more plausible possibility lies in the fact that the fruit remained on the tree longer and was exgosed to the influence of the spray materials for a greater period of time. assuming this to be true it is evident that the influence of the spray material is not altogether immediate but acts over a period of several days or weeks. Table 5. -- average number of cherries per pound for two varieties of sour cherry under various treatments at Traverse City in 1922. Treatment Varieties Montmorency English Korello Bordeaux Mixture(5-7-50) , 115 149 Lime-sulph;r (1-40) 109 116 Sulphur dust (80-10-10) 102 105 Copper dust(20-lO-70) 99 97 -15- (C) Review of field Tests in 1925 -- The Spraying season at Traverse City in 1925 was approximately two weeks later than in 192?. Following the Schedule recommended for the control of cherry leaf spot the first spray was applied on June 4. The fruit was harvested July 25. a schedule of the materials used on each plot add the average number of cherries frou each slot required to make a pound are reported in Table 4. Exmination of these data shows that again the trees Sprayed with bordeaux mixture produced the smallest cherries. Then bordeaux mixture was used in combination with lime-Silphur the re- duction in Size was not as great as where it was used alone; however, the dwarfing w,s considerably greater than where lime-sulphur was used alone. Trees in the plot Sprayed With pyrox, a commercial fungicide Contain- ing cepoer, produced slightly larger fruit than Similar trees Sp:1;ed with lime-sulphur. This material, however, caused serious injury to the foliage, resulting in heavy defoliation shortly following harvest. For this reason, it would not be satisfactory for use in a commercial cherry orchard. The two unSprayed trees produced larger fruit than that on any of the Sprayed or dusted plots. This higher average may be accounted for in part by the fact that one of the trees bore cherries of an unusual Size. This could not be attributed, at least entirely, to the fact that these trees were not Sprayed. Had there -15.- '7 been more trees from which to compute an average the size might have been nearer that for the dusted plots. Table 4. -- Everage number of Iontmorency cherries per pound under various treatments at Traverse City in 1925. Treatment Number per pound. Bordeaux mixture (3-7-50) 181 Lime-sulohur (1-33, 1st application) Bordeaux mixture (3-7-50, 2nd and 5rd). 14? Bordeaux mixture (3-7-50, 1st auplication) Lime-sulphu: (1-33, 2nd and 3rd 140 Lime-sulphur (1-55) 133 Pyrex (9-50) x 130 Cepper dust (20-10-70) 120 Sulphur dust (80-10-10) 119 Check, unsprayed. 114 Comparison of data presented in Tables 3 and 4, showing cherry Sizes under various treatments in 1922 and 1925 brings out two things: (1) cherries averlged much larger in 1922 than in 192;; (2) the dwarfing effect of certain sprays was much more pronounced in 1923 than in 1922. If the larger average size of cherries in 1922 was due to the heavier rainfall of that season, a reasonable assumption considering what is known regarding the relation of moixture supply to Size of fruit, it would seem that the relatively greater dwarfing of fruit caused by the spray materials in 1925 was in some way connected with the lower soil moisture supply or lower atmOSpheric humidity of that Season. In other words it would seem to classify rather definitely the dwariing influence of Sprays as a water relation problem. This is in line with the conclusions reached by several investigators already cited on the influence of certain sprays on the rate of transpiration. Three materials were used in Spraying tests vith two varieties of sour cherries at East Lansing in 1925. The data obtained are presented in Table 5. Bordeaux mixture (5-7-50) reduced the size in English :orello more than it did in hontmorency, a result in accord with those obtained at Traverse City in 1922. On the plot where hydrated lime alone was used in the same amount as on these plots where it was combined with cepper sulfate in bordeaux mixture the reduction in Size was not so great as where bordeaux was applied. It compared more closely to the reduction in Size produced by lime-sulphur. Table 5. Average number of cherries per pound under various treat- ments in the College orchard at East Lansing in 1925. Treatment Varieties Montmorency English HorellG Bordeaux mixture (3-7-50) 180 202 Lime~sulphur (1-40) 146 177 Hydrated lime (7-50) 178 Check, unsprayed 155 Fig. I. -- Spur and fruit from a Montmorency tree Sprayed four times during the season with bordeaux, taken September 12, 1923. . ZO Continued Influence of Spray Katerials on the Size of the Fruit. -- That the reduction in the size of the fruit Sprayed with bordeaux mixture continues as long as the fruit remains on the tree is clearly illustrated in Figures 5, 2 and 3. These Spurs were removed from Hontmorency trees in the orchard at Traverse City on September 12, l9g5. The crop was harvested on July 25. In this orchard, lime-sulphur did not cause any drying or shriveling of the fruit eXposed to the action of the spray material for seven weeks following the har- vest of the remainder of the crep. The fruit on the un- sprayed trees was just as firm and well filled out as at the time of harvest. Observations Made in 1924. -- The use of a block of Early Richmond cherries in 1924 permitted the study of a variety that ri>ens its fruit a few days in advance of the others studied. The first Spray was applied in this orchard on June 10, followed by two others before harvest. The picking records were taken on July 26. Since the applications in this orchard were intended primarily for the control of cherry leaf spot, standard dusts and liquid sprays were used for the most part. These were, however, supplemented by some additional materials. A list of the sprays and dusts used in this orchard is given in Table 6, together with the size of the fruit on the correSponding plots. Fig. II. -- Spur with fruit from an unsprayed tree taken at Traverse City, September 12, 1923. Z! Fig. III. -- Montmorency cherries on spur sprayed with lime-sulphur four times during season;taken September 12, 19:3. ~———’ *.__-»!—Hr.__.. . _.—» -19- I p.) Table 6. -- average number of Early Richmond cherries under various treatments in the Roach orchard, at Hart, in 1924 Treatment Number of cherries per pound. Bordeaux mixture (5-10-50) 140 Bordeaux mixture (5-5-50) 156 Copper dust (20-10-70) 127 Lime-sulphur (1-40) 125“ Colloidll sulphur (4-50) 122 Sulphur dust (80-10-10) 119 Unsprayed 119 Increasing the quantity of lime used in preparing the bordeaux mixture from 5 to 10 pounds, the amount of copper sulfate remaining the same, re- Sulted in a slight increase in the number of cherries re- quired to make a pound. However, both bordeaux Sprays reduced the Size of the cherries more than lime-sulphur. In this test the plot receiving cOpper dust yielded smaller cherries than that Sprayed with lime-sulphur. The trees in this plot were as vigorous and healthy as those in the other plots. The soil also was uniform for all plots in the orchard. The dust was applied either in the early morning or evening and at a time when conditions were very favorable for dusting. N - 20 - The method of application was the same as that followed in the two preceding Years at Traverse City, which gave practically the same sized fruit on both of the dusted plots. The plot sprayed with colloidal sulphur produced cherries slightly larger than those on the lime-sulphur Sprayed plot, although leaf spot control was not as good. Relation of Densipy of Film of Spray Material on the Foliage to the Size of the Fruit. -- Observations made in 1923 of sprayed and dusted foliage in the Hontmorency orchard at Traverse City led to the belief that the heavier the film of material on the foliage was the smaller the cherries would be. No methods were devised that would accurately measure the film of Spray material on the foliage. However, photo- graphic records were obtained of a number of sprayed leaves taken from the plots under observation, as shown in Figure 1‘ From these photographs a fair idea may be secured as to the amount of spray material on the fol- iage and the extent to which the leaf surface was covered. Comparison of the sprayed leaves in-Figure ¥with the size of cherries for the respective treat- ments as given in Table 4 shows that bordeaux mixture produced the most obvious film of material of any of the sprays used, while at the same time it resulted in cherries of the smallest size. Lime-sulphur and py ox, tne other sprays, cocoared it: Figure 4, did not produce 25 Fig. IV. -- Cherry leaves sprayed with various materials showing the film produced. A, unsprayed; B, pyrox; C, lime-sulphur; D, bordeaux mixture. 7/ as heavy agparent coating of the leaf or as complete a coverage as did the bordeaux mixture. The size of the fruit was corresuondingly larger than that on the bordeaux- sprayed plot. a s'mi er correlation between the amount of dens ty of filn of spray material and size ofifruit was observed on other plots of the orchard. A similar comparison was made with three spray materials in the orchard at East Lansing where blocks of English Horello trees were sprayed with bordeaux mix- ture, lime-sulphur and hydrated lime respectively. Here again the same relation between the amount of spray material on the foliage and size of the fruit was found to exist as in the Hontmcrency orchard at Traverse City. The spraying experiments at Hart in 1924 permitted further comparison of the effect of a number of materials on the amount of the film of material on the foliage and the resulting fruit size. In this orchard a comvarison was made between two bordeaix mixtures, one of which contained ten pounds of lime, while the other was made with only five pounds of lime. Typical leaves from each of these 1015 are the n in Figure 8: The ’0 leaves sprayed with the bordeaux mixture containing five pounds of lime produced a slightly lighter film and slightly larger fruit than those on which the mixture containing ten pounds was used. With the exception of the plot receiving copper dust all plots in this orchard produced fruit of a size that was, roughly, inversely -- ~4- pr0p01tionate to the amount of material apparent on the Z7 Fig. V. -- LeaVes of Early Richmond cherry showing the amount of bordeaux mixture present when the quantity of lime is varied. A, ten pounds hy- drated lime to three pounds of copper sulphate and 50 gallons of water; B, five pounds hydrated lime to three pounds copper sulfate in 50 gallons of water. r \J CK.) - 22 - foliage. More data bearing on this particular question are furnished by an eXperiment conducted in the Maynard orchard near Grand Rapids in 1924. The spray materials used were: bordeaux mixture (3-5-50); lime- sulphur (1-40); lime-sulphur 1-40 plus 5 pounds of hydrated lime); colloidal sulphur (4-50). Chock trees were left at convenient places in the orchard to give a fair average for unsprayed trees. The first spray was applied on June 6; it was followed by two others, on June 20 and July 8 respectively. The fruit was harvested on July 23. The average number of cherries to the pound in each plot are shown in table 7. Table 7. -- Average number of Montmorency cherries per pound under various treatments in the Maynard __ orchard, at Grand Rapids, in 1924.' $_ Treatment Number of Cherries Bordeaux mixture(3-5-50) 108 Lime-sulphur(l-4O plus 5 lbs. hydrated lime) 100 Lime-sulphur (1-40) . 94 Colloidal sulphur (4-50) 91 Unsprayed. 9O Owing to heavy rainfall throughout the early part of the season and frequent rains until harvest, the cherries on all plots were larger than in - 23 . any of the other ochards studied. The differences, however, were similar taaszfifir to those recorded for the preceding years with the same and with other varie- ties. Bordeaux mixture prepared with 5 pounds of hy- drated lime retained its position in its dwarfing effect on the fruit. The use of five pounds of hydrated lime to each 50 gallons of the lime-sulphur spray did not reduce the size of the fruit as much as the bordeaux mixture but it did diminish the size more than the use of lime-sulphur alone. Colloidal sulphur resulted in very little decrease in the size of the fruit. The addition of five pounds of lime to the lim-sulphur solution did not leave the heavy deposit on the leaf surface characteristic of the bordeaux mixture. However, the entire leaf surface was covered with a light film. Lime-sulphur alone covered less of the foliage than did either of the other two sprays Just mentioned. The presence of colloidal sulphur on many of the leaves could ‘ not be detected by the eye, while on other leaves a slight deposit of material was visible near the margins of the leaf; this gradually faded away a short distance from the margin. Detail Studies in Orchard and gatoratory; -- In order better to determine the reason for the dwarfing of the fruit, studies were made of detached branches from English Morello trees in the sprayed plots in the orchard at East Lansing in 1923. A description of the sprays used has been given in (\‘J .3 0 connection with Table 5. Effect of Spraygnaterials on the Rate of Wilting -- At 1:00 P. M. on Judy l unifbrm late of shoots were removed from each of three plots and taken to the laboratory where they were spread out on a table to Wilt. The temperature of the room at this time was 78 degrees F. Notes wereitaken at intervals during the afternoon and the following morning as to the condition of the leaves. The data collected are shown in Table 8. The leaves on the branches with fruit attached dfl not wilt as rapidly as did those on the shoots with cherries removed. From this it may be concluded that the leaves were drawing water from the fruit, due to the difference in osmotic concentration in these two parts, as has been shown by the work of Chandler (17). In the series where the fruit was left attached to the branches, the order of wilting as shown by the turgidity of the leaves was: bordeaux first, lime-sulphur second, and unsprayed last. The leaves on both shoots sprayed with bordeaux mixture had dried at the end of 16 hrs. until they could be broken when crushed in.the hand. gate of Water Loss when Tilting. -- A similar series of shoots was secured on July 2, taken to the laboratory where they were exposed to the air under the same conditions as those on the previous day. Each branch was weighed hourly during the day to determine the rate at which drying occurred. At the close of the test the areas of all the leaves on each shoots were measured 2 .mm. ensue m., aoamm on «so Hmdm we saws: aaamosma owesaw debQUom auwdmn sauce Ilwmdoumdosw nonapeposmkuspm H. Homu. seaweeds» anew swuoaen mos spwawsm. aBHpe H mu... HIQRN 5H. dd”. HQIHHHO H dsmwsmwan Hcm\/ mu... .Oq wouaomsn I .om ”Boumsvwwsu .om asmwumaan .8. .Ou .om .OH v-". .00 r'l|'l 1P m away menus as am msoswnm swam ow scams Homm waosdowmewawmmwwwM can oxvommn wwm. WWW. mwumwww swan @memaoad deoawmwm. atom on m mo MD m swam woos. muuo HH sumo 2. L 5’ Wu... .OQ .om .om .o¢ .Cm .om .OH .00 .OH .I 1.: I I.u..woumownfl Sunfisao Hpaoamgjwusn dsmwemwma \irlll N l/ ; \w ll, \ alllll, ::.: z . . n o «"00 came Houmo kumo Hmumo Hume muuo mum p.mo u.uo m u U y H . 2C. shoots were taken to the laboratory where buds were out under water and immediately sealed in graduated glass cylinders containing tap water. When all were ready they were removed to a bench in an open space outdoors, where the exposure to sunlight and wind was similar to that in the orchard. Readings were made at frequent intervals during the day showing the amounts transpired by the leaves of the various lots. After a 48~hour period, the final reading was made and leaf area measured for each shoot. The data obtained are recorded in Table 9. Spraying with bordeaux mixture or lime-sulphur solution increased the quantity of water transpired.over that of unsprayed shoots. It is also evident that branches with cherries attached took up more water per unit of leaf area than did those whose fruit had been removed. A duplicate test starting at 11:00 A. M. and closing at 6:00 P..M. on July 5 gave similar results. Table 9. -- Transpiration water loss in c.c. per unit of leaf from detached cherry shoots for a 48-hour period ___from 9:00 A. M., July 2 to 9:00 A. My guly 5: 1923. *Lea a er ya er oss Treatment Condition Area loss per unit sq. in Of in. c.c. leaf area. Bordeaux miffur Witfio ut fruit“'26. 4 58' 2.19 Lime-sulphur 25. 9 52 2.01 Unsprayed “ " 26. 5 52 1.96 Bardeaux mixture “fl" " 21.9 62 2.83 Lime-sulphur " ” 26.5 67 2.54 Unsprayed " ' 23.1 53 2.25 C -28- The greater water intake of the shoots bearing fruit might ccnceivably be due to greater transpira- tion by the leaves or by the fruit or it may be due to the re- tention of water by the fruit. To secure some indicatinn as to which of these factors is operative, two sets of branches were selected from each of the plots under obser- vation at East Lansing. These were similar to those used in the previous test, but the terminal leafkbearing wood was removed in this case. The twigs were set in.graduated glass cylinders as before. In one lot the fruit was dipped in warm paraffine to prevent loss of water from .the surface of the fruit while the others were left un- treated. All shoots bore the same number of cherries of about the same size and degree of maturity. All were exposed to atmospheric conditions similar to those in the orchard for a 48-hour period and the amount of water taken up was then calculated per cherry. A study of the data presented in Table 10 shows that branches with uncoated cherries took up over four times as much water as those whose fruit was protected with paraffine. This would indicate that water was being evaporated from the fruit in large quantities. It will also be noted that when they were sprayed with bordeaux mixture or lime-sulphur the water loss was much greater than in those on which no spray was applied. However, all the water taken up was not transpired as is shown in the figures for the cherries dipped in paraffine, but it was used to supply an apparent E7 . 29 - deficit within the fruit at the time it was removed from the tree. Table 10. Amount of water taken up per cherry by shoots bsaring green fruit. Data represents a 48-hour period starting at 8 A. M. July 51 1923. Treatment Cherries Cherries paraffined unparsffined Cece 6.0. Bordeaux mixture .43 1.78 Lime-sulphur .15 .78 Unaprayed .06 .57 It has been pointed out that under condi- tions of water stress within the plant there is evidence 6f a withdrawal of water from the fruit to the leaves to replace that which is being transpired. Some measure of the rate of this movement of water from the fruit to the leaves was obtained by injecting a concentrated solution of lithium nitrate into green cherries on trees in each of the plots under observation. Leaves adjacent to the fruit were removed at intervals and preserved for spectroscOpic examination of the ash for the presence of lithium. Some of the records that were obtained are pre- sented in Table 11. Evidently, the presence of bordeaux mixture on the foliage hastened the movement of water from the fruit to the leaves. The movement was slower where lime sulphur was used but not as slow as where no ImOl awdwm Hp. 1: wade ma aspen swans Bo