ANNUAL REPORT, 1935 41 



Percentage of Fruit Showing 

 Percentage Injury from — 



Dosage per of Clean 



Treatment 100 gals. Fruit Curculio Codling Scab 



Moth 

 A TPslcPt" 6 h oz. 



300-mesh sulfur ; .'".".'.'.'.'.'.'.'.".'.'.'.'.'.'.'. .11 lbs./ 68.4 3.2 1.0 22 



Dry lime-sulfur 4 lbs. \ 



Flotation sulfur 2]/ 2 lbs. / 84.5 6.8 3.4 1.5 



Dry lime-sulfur 6M lbs. 88.7 1.0 0.9 5 



Dry lime-sulfur 8 lbs. 92.8 1.9 T 0.5 



Kolofog 6 lbs. ] 



Fluxit 1 lb. \ 38.4 9.1 3.6 57 



*Lime 6 lbs. J 



Sulcoloid 5 lbs. \ 



tLime 5 lbs. / 90.9 1.5 1.9 2.2 



Check (unsprayed) .6 37.7 15.2 95.8 



♦Added in 3d and 4th Cover Sprays. 

 tAdded in Calyx and 1st Cover Sprays. 



Scab proved to be difficult to control in 1935 so that all treatments were 

 subjected to great difficulties and few, if any, gave as good results as in more 

 normal seasons. Accurate timing of the sprays in connection with scab devel- 

 opment was essential. This development varied in different blocks and caused 

 greater variation in control from the same material in different blocks than 

 between different materials in the same block. In the tests reported above, 

 considerable scab was present on trees sprayed with, the Kolofog-Fluxit-lime 

 mixture, yet in another block of the college orchard this same combination of 

 the same dosage held scab to 0.6 percent injury and showed 91.7 percent clean 

 fruit. 



Control of White Apple Leafhopper with New Pyrethrum and Pyrethrum- 

 Nicotine Sprays This Department cooperated with the Crop Protection 

 Institute in tests with two of their newly developed pyrethrum products for 

 the control of the second brood of white apple leafhopper in several com- 

 mercial orchards. The products, designated DX75 (pyrethrum) and DX57 

 (pyrethrum-nicotine), were applied at a dilution of 1 pint — 100 gallons of 

 water. One application of these materials in one commercial orchard reduced 

 the average infestation from 12 hoppers per leaf to 0.7 on Baldwin, a 95-97 

 percent reduction. In a second orchard the hopper infestation on Mcintosh 

 was reduced from 4.3 per leaf to 0.12, approximately 97 percent control. The 

 results in all the orchards were uniformly satisfactory. Growers found none 

 of the objectionable features of heavy nicotine applications in using these 

 materials. They were applied in several tests on cloudy days and at low 

 temperatures, in some cases during a light rain — conditions in which nicotine 

 sprays would be out of the question, yet the effectiveness of these DX sprays 

 was not materially lessened. They show excellent promise. 



Control of Striped Cucumber Beetle with Derris and Pyrethrum Dusts. Summer 

 squash and cantaloupe at the Waltham Field Station were dusted to prevent 

 injury by the striped cucumber beetle. The dusts included two commercial 

 derns mixtures containing .55 percent rotenone, homemade mixtures of derris 

 and clay containing .6 percent rotenone with and without 40 percent sulfur, 

 a 30-70 pyrethrum-clay mixture, and a 10-20-70 calcium arsenate-monohy- 



