ANNUAL REPORT, 1939 47 



Control of Bud Moth with Dormant Sprays. In cooperation with the Dow- 

 Chemical Compan>- and H. A. Priest, nine blocks of trees at Fruit Acres, Gleason- 

 dale, infested with the bud moth, were sprayed with combinations of dinitro- 

 ortho-cyclo-hexylphenol (DNOCHP) and dinitro-orthocresol in oil, furnished by 

 the Dow Chemical Company; and sodium dinitro-cresylate, and oil emulsion 

 plus nicotine sulfate, furnished by the owner. Approximately 5000 gallons of 

 spray were applied to 600 trees in the experiment. Application was started on 

 April 23 when the buds were in the bilver tip stage but was discontinued at noon 

 because of wind and completed on April 24. Three count trees were selected from 

 each plat and an adjoining unsprajed block was used as a check. A bud examina- 

 tion was made on these trees on May 24-25 when most of the trees were in bloom, 

 and the fruit was examined at the regular harvest period for the variety. 



In comparison with a bud infestation of 62 percent and fruit infestation of 

 23.86 percent in the check, all treatments gave excellent control of the bud moth. 

 Considerable injury occurred, especially to leaf buds on one-year-old twigs and 

 also to fruit buds. This injury was most serious where DNOCHP in oil was used 

 on Gravenstein, Yellow Transparent, and Mcintosh. Russet trees sprayed with 

 a tank-made mixture of the same materials showed little or no injury. Injury 

 was much more severe on large trees where the drip and drift from the upper 

 branches caused excessive drenching of the lower branches. The DN cresol 

 mixtures appeared least injurious to the trees and gave satisfactory control 

 of the bud moth. 



Summer Sprays for Apples. Tests of these materials were conducted in co- 

 operation with the Departments of Pomology and Botany. The widespread 

 damage caused by the hurricane of September 1938 throughout most of the 

 fruit-growing sections of the State naturally led to a study of modifications of the 

 spray program to reduce as far as possible the danger of spray injury to weakened 

 trees and at the same time retain an efficient control of disease and insect pests. 

 Although the hurricane injury in the test block was not so extensiv^e as in more 

 exposed sections of the college orchard, there had been sufficient injury to warrant 

 the use of this block for such studies. 



The tests included commercial lime-sulfur at a reduced strength of 1^ gallons 

 per 100 with spray catalizer, similar tests of lime-sulfur at reduced strength with 

 hydrated lime to retard breakdown, two combinations of lime-sulfur and wettable 

 sulfur at half strengths, wettable sulfur at full strength throughout the season, 

 and a wettable sulfur with orthex sticker. All of the above combinations were 

 used in the pre-blossom and calyx sprays followed by wettable sulfur in the four 

 subsequent applications. The standard schedule of lime-sulfur 2 gallons per 100 

 in the pre-pink, pink, and calyx sprays, and wettable sulfur thereafter, was used 

 as the basis of comparison. Lead arsenate was omitted in the pre-pink applica- 

 tion but was included in all others. The dosage was 3 pounds per 100 gallons 

 in the pink and 3d cover sprays; 4 pounds per 100 gallons in the calyx, 1st and 

 2d cover sprays; and 2 pounds per 100 gallons in the 4th cover spray. Linseed 

 oil was ued in the 1st cover spray. 



Examination of the block in early June showed noticeable dwarfing and crink- 

 ling of leaves in the trees given the standard schedule. This condition was also 

 present, but to a noticeably less extent, on trees sprayed with lime-sulfur at 

 reduced strength with spray catalizer and lime. The trees which had received 

 the combinations of lime-sulfur and wettable sulfur at half strengths showed no 

 injury up to that time. This was also true where wettable sulfur alone or with 

 orthex sticker was used. Up to that time scab was being successfully controlled 

 in contrast with the unsprayed checks where the foliage was already showing 

 heavy infection. Later in the season when all the trees received wettable sulfur, 



