NN 2 245 s CONNECTICUT nca^S" Agricultural Experiment Station NEW HAVEN, CONN. BULLETIN 245 FEBRUARY, 1923 Results of Dusting Versus Spraying in Connecticut Apple and Peach Orchards in 1922 By M. P. Zappe and E. M. Stoddard. CONTENTS Page Apple Orchards 229 Materials Used ' 230 Apparatus Used 230 Method of Recording Data 230 Orchard No. I 231 Orchard No. II 233 Orchard No. Ill 236 Orchard No. IV 240 Peach Orchards 242 Results of Treatment in Peach Orchard No. I 242 Results of Treatment in Peach Orchard No. II 242 Summary 243 The Bulletins of this Station are mailed free to citizens of Connecticut who apply for them, and to other applicants as far as the editions permit. CONNECTICUT AGRICULTURAL EXPERIMENT STATION OFFICERS AND STAFF February, 1923. BOARD OF CONTROL. His Excellency, Charles A. Templeton, ex-officio, President. James H. Webb, Vice-President Hamden George A. Hopson, Secretary Mount Carmel E. H. Jenkins, Director and Treasurer New Haven Joseph W. Alsop Avon Charles R. Treat Orange Elijah Rogers Southington Edward C. Schneider '. Middletown Administration. Chemistry. Analytical Laboratory. Biochemical Laboratory. Botany. Entomology. Forestry. Plant Breeding. Tobacco Sub-station at Windsor. = Assistant Chemists. STAFF. E. H. Jenkins, Ph.D., Director and Treasurer. W. L. Slate, Jr., B.Sc, Vice-Director. Miss L. M. Brautlecht, Bookkeeper and Librarian. Miss J. V. Berger, Stenographer and Bookkeeper. William Veitch, In charge of Buildings and Grounds. E. M. Bailey, Ph.D., Chemist in Charge. R. E. Andrew, M.A. C. E. Shepard Owen L. Nolan Harry J. Fisher, A.B. Frank Sheldon, Laboratory Assistant. V. L. Churchill, Sampling Agent. Mrs. B. P. Storrs, Clerk. T. B. Osborne, Ph.D., Sc.D., Chemist in Charge G. P. Clinton, Sc.D., Botanist in Charge. E. M. Stoddard, B.S., Pomologist. Miss Florence A. McCormick, Ph.D., Pathologist. G. E. Graham, Assistant. Mrs. W. W. Kelsey, Secretary. W. E. Britton, Ph.D., Entomologist in Charge; State Ento- mologist. B. H. Walden, B.Agr., M. P. Zappe, B.S., ^Assistant Philip Garman, Ph.D., f Entomologists John T. Ashworth, Deputy in Charge of Gipsy Moth Work. Samuel T. Sealy, Deputy in Charge of Mosquito Control. Miss Gladys M. Finley, Stenographer. Walter O. Filley, Forester in Charge. A. E. Moss, M.F., Assistant. H. W. Hicock, M.F., Assistant. Miss Pauline A. Merchant, Stenographer. Donald F. Jones, S.D., Plant Breeder in Charge. P. C. Mangelsdorf, B.S., Assistant. G. H. Chapman, Ph.D., in Charge. Results of Dusting Versus Spraying in Con- necticut Apple and Peach Orchards in 1922. By M. P. Zappe and E. M. Stoddard. This series of experiments with dust in comparison with liquid sprays for controlling the common insect and fungous pests of apple orchards in Connecticut was begun in 1920. The results of that year's work were printed in the Station Report for 1920, pages 168-177. In 1921 the project was enlarged to include peaches. Four apple and two peach orchards were used and the results of the work published in Bulletin 235 of the Station, and in Crop Protection Digest No. 2, page 7. In 1922 the same or- chards were used as in preceding years. APPLE ORCHARDS. ) Orchard No. I. Young orchard, Station Farm, Mount Carmel 96 trees Orchard No. II. Orchard of W. F. Piatt, Orange 62 trees Orchard No. III. Orchard of F. N. Piatt, Milford 285 trees Orchard No. IV. Old orchard, Station Farm, Mount Carmel 40 trees 483 trees A portion of the dusting materials was furnished gratis to Dr. W. E. Britton, Entomologist of this Station, on behalf of the Crop Protection Institute by the Dosch Chemical Company of Louis- ville, Kentucky, and we hereby express our appreciation and thanks for this favor. We also desire to express our appreciation and thanks to Messrs. W. F. Piatt and F. N. Piatt for the use of their orchards and spray outfits, also for their co-operation in this work. We also wish to thank Dr. B. A. Porter, in charge of the Wallingford Field Station of the Bureau of Entomology, for the use of the dusting machine and for his assistance in scoring the fruit. Mr. G. E. Gra- ham of the Botanical Department of this Station assisted in ap- plying the treatments and scoring fruit. Messrs. W. E. Britton, B. H. Walden and P. Garman of the Entomological Department, and Messrs. F. D. Luddington and J. L. Rogers, temporary employees, assisted in gathering and scoring the fruit. The owners of the Or- 230 CONNECTICUT EXPERIMENT STATION BULLETIN 245. chards furnished spray outfits with team and driver for each of the spray applications in orchards II and III. MATERIALS USED. SPRAYS. The liquid spray for all treatments in all orchards was as follows : Commercial Lime-Sulphur 3 gallons Lead Arsenate (Dry) ; 3 pounds Nicotine Sulphate 24 pint Water 100 gallons DUSTS. Sanders or Copper Dust. Dehydrated Lime 79 per cent. Dehydrated Copper Sulphate 13 per cent. Calcium Arsenate 8 per cent. Sulphur-Nicotine-Arsenate Dust. Superfine Dusting Sulphur 65 per cent. Lead Arsenate 10 per cent. Nicotine Sulphate 5 per cent. Carrier 20 per cent. 90-10 Sulphur-Arsenate Dust. Dusting Sulphur 90 per cent. Lead Arsenate 10 per cent. APPARATUS USED. The dusting machine used in all the orchards was a Niagara duster owned by the Bureau of Entomology and used at its Field Station at Wallingford, Connecticut. The machine was designed to be drawn by a team of horses, but this method was too slow when moving the outfit from orchard to orchard, so. the machine was mounted on a Ford ton truck, thus saving considerable time on the road and in the orchards. The Ford truck had no trouble in carrying this outfit through the orchards. When the machine was not in use it could easily be unloaded from the truck and stored in a shed. In orchard No. I, an Arlington X. L. power sprayer with a 100 gallon tank was used. Two lines of hose were used with a nozzle at each rod. In orchards No. II and III, Friend power sprayers with 200 gallon tanks were used. In orchard No. II, spray rods were used, one man spraying from the tower and the other from the ground. The pressure was about 200 pounds. In orchard No. Ill, a single line of hose with a "spray gun" carry- ing 175 pounds pressure was used, spraying from the ground. METHOD OF RECORDING DATA. Certain trees promising a crop situated inside the border of each plot and representing the chief varieties upon which the tests RESULTS OF DUSTING VERSUS SPRAYING IN CONNECTICUT. 23 1 were made in each orchard were selected and marked as count trees. As a rule the count trees were selected near the center of each plot and not adjacent to a plot having a different treatment on account of the danger of spray or dust getting on the trees that were not intended to be so treated. With the liquid spray there is less danger of this, but the dust is quite apt to drift. or be blown upon adjoining trees. The green dropped fruit from each of the count trees was gath- ered, counted and examined for insect and fungous injuries and the data recorded for each tree twice before the ripe fruit was picked. At harvest time the picked fruit was scored in the same manner. Each individual apple was carefully examined and a record made of each insect and fungous injury. Apples that were called "good" were absolutely free from any signs of insects or fungous diseases and might better be called "perfect", for they were free from pests and were perfect except possibly as to size. An apple showing the work of more than one pest would be checked as many times as there were kinds of insect injury or fungous diseases. This very often gave a greater number of injur- ies than there were apples, and in order to get the true amount of any kind of injury all the apples had to be counted, and this num- ber used to compute the percentage of injury or the percentage of good fruit. This scoring of the fruit involved examining separate- ly 181,036 individual apples, equivalent to about 402 barrels. The figures given in the tables of results from the various plots are percentages of perfect fruit or of injuries even if very slight, and cannot be compared with any commercial grading. For in- stance, an apple that had been bitten by a curculio might only have one or two small blemishes and would be counted as a "curculio" apple, but in a commercial grading of the fruit would easily go as a No. 1 apple. The same is true of other injuries, especially small spots of scab, sooty blotch or fruit speck. After scoring the apples by the above method, all the fruit on the count trees was graded as it would be for market. The results obtained by the commercial grading method are of the greatest importance to the fruit grower, and tell at a glance which treatment gives the highest per cent, of No. 1 fruit. The other method of scoring is of value in showing just where certain treatments fail. ORCHARD NO. I. Orchard No. I was the eleven year old Experiment Station or- chard located at Mount Carmel. This orchard is just begining to bear, and consists of 96 trees on a side hill sloping to the west. All trees bearing fruit were used as count trees to check up results. The varieties were Baldwin, Rhode . Island Greening, Roxbury Russet, Mcintosh, Gravenstein, Duchess of Oldenburg, Fall Pip- 232 CONNECTICUT EXPERIMENT STATION BULLETIN 245. pin, Northern Spy, Sutton Beauty, King, Wealthy, Hurlbut and Stark. This orchard was divided into three plots. The north plot was treated with liquid spray and the south plot with the 90-10 sul- phur dust. The remaining plot in the center of the orchard was used as a check. The green dropped fruit was gathered, counted and scored twice during the summer. At harvest time all the picked fruit was scored. All trees that bore fruit were used as count trees in this orchard. NUMBER AND DATES OF APPLICATIONS. The first application of spray and dust was given this orchard on April 29, when the blossom buds began to show pink. The second application was the calyx spray, made on May 22., just after all the petals had fallen. The next treatment was given on June 14. To test the value of later applications of spray and dust, the plots were each divided into two equal parts. One half of each original plot received two more applications of spray and dust while the other half had no further treatment. The two later ap- plications were made on June 30 and July 20. The spray and dust were always applied on the same day. The dust was put on first, very early in the morning before the wind began to blow and often while the trees were still wet with dew. Later in the day, or as soon as the dusting operations were finished, the liquid spray was applied. As there were no sucking insects present, nicotine sulphate" was omitted from the last two sprayings. Table No. I. Results of Treatment. All Varieties. J3 to 4J c 0 C bo* ,2 v O bo C .2 c ■3 " 0 V m • M S c QJ 60 c 3*S ft c V TjU ,2U MO = u 3" fcu „u O u •S.1- T3 u t3 u - s- A L- nl 1- •a u Treatment. O V Oft 0 Oft Spray, _ 5 applications . . . J5-2 18.85 O I.I 71.9 1.9 H-59 2.8 Sul.-Nic.-Ars. Dust, 5 applications . . . 15-2 12.49 ■054 2.8 80.4 2.9 2.06 5-3 1.49 177 .199 20.4 95- 6.5 8.9 55-i Spray, 3 applications .... 17.7 II-3 0 2.6 70.5 2.9 10. 1 5-4 Sul.-Nic.-Ars. Dust, 3 applications . . . 11.05 17.6 .047 4-3 81.7 3-3 5-68 10.3 DISCUSSION OF RESULTS. In this orchard there were many varieties, some of which were represented by only a few trees, so that each variety could not be RESULTS OF DUSTING VERSUS SPRAYING IN CONNECTICUT. 233 included in each plot. For instance, the Mcintosh variety was in- cluded only in the sprayed plots ; none in the dust plots. There were no varieties that scab badly in either of the dust plots ; there- fore the percentage of scab in the sprayed plot is naturally higher than in the dusted plots. The percentage of good fruit in this or- chard was very low on account of the great abundance of curculio injury. In nearly every case the liquid spray was a little better than the dust treatment. The plot receiving the dust treatment was much better than the check or untreated plot. In the column called "other insects" are included chewing insects which are nor- mally controlled by arsenate of lead. The "other fungi" column includes sooty blotch, fruit speck, bitter rot and cedar rust. The injury from red bugs in this orchard was negligible. FIVE TREATMENTS VERSUS THREE TREATMENTS. In most cases the spray or dust plots having five applications gave a lower percentage of insect and fungous injury than the plots having but three applications, exceptions being the case of curculio injury in the spray plots, the good fruit in the sprayed plots, the scab results in both spray and dust plots, and aphis re- sults in both sprayed and dusted plots. In the case of scab results the difference is easily explained. The scab susceptible varieties were not equally represented in the various plots, there being more varieties that scab easily in the sprayed than in the dusted plots. The spray plot having the extra treatments was on the northern edge of the orchard and it is a common occurrence for the trees along the border of an orchard to show greater curculio injury than trees further back from the margin. The curculio injury is caused early in the season, soon after the young fruit has set, so that the later treatments would have no effect on this insect. The extra treatments showed a little better codling moth control, evi- dently on the second brood worms. The "other insects" being later feeders on the surface of fruit, would naturally be better controlled by later treatments of spray or dust. The 'same is true of the fungi which make their appearance later in the season, with the exception of scab. ORCHARD NO. II. This orchard is owned by Mr. W. F. Piatt, located in the town of Orange, near the Milf ord line. It is twenty-eight years old and has been kept in very good condition. There were three experi- mental plots in this orchard ; the spray plot, consisting of 33 trees ; the dust plot of 25 trees, and the check plot of four trees. The varieties in the experimental plots in this orchard were Fall Pippin, Mcintosh and Greening. Each variety was repre- sented in the spray, dust and check plots, except that there were 234 CONNECTICUT EXPERIMENT STATION BULLETIN 245. no Fall Pippins in the check plot. Count trees were selected soon after blooming and trees that gave promise of having a good crop were selected. Two trees of each variety were selected in each plot, one receiving the five treatments and the other the three treatments. The number and dates of application were the same as those in orchard No. I. The owner of the orchard put on the regular de- layed dormant spray over all the plots, also the pre-pink spray on all Fall Pippin and Mcintosh trees. The regular spraying and dust- ing operations began with the pink treatment on April 28, followed by the calyx application on May 19. The first treatment after the calyx was applied on June 13. After this treatment the spray and dust plots were divided into two parts, one part of which receiv- ed two further applications of spray and dust, while the other had no further treatment. In this orchard the liquid spray was put on with a Friend power sprayer, using two lines of hose with two nozzles at each rod. One man sprayed the tops of the trees from a tower on the spray out- fit while the other sprayed the lower part of the tree from the ground. The regular lime-sulphur arsenate of lead spray with the addition of Black Leaf 40 was used. The dust Was applied with the same duster used in the other orchard. Only one kind of dust was used in this orchard, namely, the sulphur-nicotine dust. About three or four pounds of dust were used per tree. Table No. II. t Results of Treatment. Greening. J3 CO • fM O 0 ho +j 4-J hn"*"* gj r\ ■** CD to . +j a 3 -m a V a CD ,5 v |-8 M ID a CD M CD TJU .20 By 2U gu CD w .*,<-> CD ^ 0 u ■fl u t> u "O u 1- u JZ !- rt *-< J3 u O CD Oh (U CD CD O V 3 dj -M CD CJ CD -u CD Treatment. OFM 3^ £U „u SjU 8 u '■£ k. T3 u -a u >- 1* J3 1- rt •- — Vh Treatment. O tU OPh «Ph 0 5 u c/iP-i OCL, Spray, _ 5 applications .... 40. 5-27 •44 •34 2.8 •54 54-5 4.38 Sul.-Nic.-Ars. Dust 5 applications .... 6.39 9-54 .09 .18 3.56 .647 86.4 •55 Checks .121 2.9 .026 78 .227 4.4 .06 35-3 2.26 3-H 1.74 98.4 54-7 9.11 .166 Spray, 3 applications . . . 44.4 Sul.-Nic.-Ars. Dust, 3 applications .... 5.06 3.58 .117 •3ii 4.66 i-55 96. 2.62 DISCUSSION OF RESULTS. Here the liquid spray is again better than the dust treatments, particularly in the control of scab. The percentage of good fruit is very much greater in the sprayed plots both for the three and five treatments than in dusted plots. In control of other pests, the difference is not so marked. The difference noted in control of fungi on Greenings is more evident than in the case of Mcintosh, probably because the Mcintosh does not seem to be so susceptible to these diseases, as the check plot shows only nine per cent, of injury in this column. Table No. IV. Results of Treatment. Fall Pippin. Treatment. Spray, 5 applications Sul.-Nic.-Ars. Dust, 5 applications Spray, 3 applications Sul.-Nic.-Ars. Dust, 3 applications No checks. -dU .S£U O UPh 3 — Ui OP* .387 2.56 1.35 64.4 6. .326 5-62 1.44 94-5 23. ■247 3-99 -846 79-5 6.6 .52 6.4 1.95 94-9 48.6 236 CONNECTICUT EXPERIMENT STATION BULLETIN 245. DISCUSSION OF RESULTS. The results in the Fall Pippin plot are similar to those obtained in the other plots, the liquid spray again giving a higher percentage of good fruit and a very much lower percentage of scabby fruit also a much lower percentage of fruit showing the injury of sooty blotch and fruit speck. The differences in control of insect pests are not so evident as in the case of fungous diseases. There were no check trees left in the Fall Pippin plots, but in preceding years the fruit was absolutely worthless, showing nearly ioo per cent, of scab. ORCHARD NO. III. This orchard is located two miles north of the village of Mil- ford and is bounded on the east side by a highway running north and south. The trees are 18 years old, and are located on a fairly level piece of land with woods on the west and open fields on north and south sides. The trees had dense crowns, making it rather difficult to reach the centers with spray or dust. The varieties used in the experimental work in this orchard were Baldwin, Greening, Gravenstein and Mcintosh. This or- chard was divided into four plots, one for liquid spray, two for dust and one for check. Two kinds of dust were used, Sanders or copper dust, and sulphur-nicotine-arsenate dust. Count trees were selected soon after blossoming, and the green dropped fruit from them gathered, counted and scored twice during the summer. At harvest time the fruit remaining on these trees was gathered and scored. ' The applications of spray and dust were put on at approximate- ly the same dates as those of Orchard No. II. This orchard had no delayed dormant treatment nor any pre-pink spray, the first being applied when the blossom clusters had separated and were showing pink. As in the other two orchards the spray and dust plots were divided after the third application, one-half of each receiving two more treatments, while the other had no further ap- plications. The spray outfit used here was also a Friend machine, but a spray gun was used instead of spray rod as in orchard No. II. The same duster was used here as in the other orchards. The dusting was always done on the same day and usually before the spray was applied. One day the wind was too strong for dusting, so that it had to be put off until the evening of that day. RESULTS OF DUSTING VERSUS SPRAYING IN CONNECTICUT. 237 Table No. V. Results of Treatment. Baldwin. -*J hn-H 0 rt -*-* U an c 3-W a a 3 C be C .2 c mC a fa C -< J3 h 0 V — OJ Cj (U 0 1) 3 Treatment. OPh T3 u V- ;-, J3 1- rt u •C U 0 O UPm UPh OPh C/2CL, OPh .087 1.03 29.54 2.53 23.14 4.09 5-03 .148 5i-7 46.7 DISCUSSION OF RESULTS. In this orchard there was very little difference between the two kinds of dust. The percentage of good fruit was very nearly the same, while in the control of fungi the Sanders dust gave slightly better results. The other differences are so slight that they are hardly worth mentioning. Table No. XL Results of Treatment. Greening. Treatment. Sul.-Nic.-Ars. Dust. Sanders dust c v 2 <- OPh 18.05 22.5 B •5 t-