ANNUAL REPORT. 1940 33 



day showed a shrinkage of 14.1 percent when stored in 50 pound crates, 

 and 22.7 percent when stored in 50 pound bags. 



In rotation experiments the shrinkage after 90 days in storage of onions 

 grown after one year hay sod was 13.5 percent; of onions after a ryegrass 

 cover crop, 22.4 percent; and of onions directly after onions, 17.3 percent. 

 These are the first year's results on land which has produced onions con- 

 tinuously for more than 40 years. 



Miscellaneous Tests and Experiments. (E. F. Guba and C. J. Gilgut, 



Waltliam.) 



i. Apple Scab Control. Wettable sulfurs used on an equivalent sulfur 

 basis were compared for scab control, fruit russet, and leaf injury. All 

 applications, except the pink and third cover sprays, contained 3 pounds 

 of lead arsenate to 100 gallons of spray with or without 6 pounds of lime. 

 Seven applications were made, beginning with the pre-pink on May 9 

 and ending on July 8. Delicious, Mcintosh, and Greening varieties were 

 used during the experiment. Fruit russet was found only on Delicious. 



Kolofog, 6 pounds to 100 gallons, and micronized sulfur, 1.8 pounds to 

 100 gallons, used with 3 pounds of lead arsenate and with or without 6 

 pounds of lime, gave good control of scab on all three varieties of apples 

 sprayed. Fruit russet produced by the Kolofog-lead arsenate spray was 

 reduced from 17.9 percent to 9.6 percent when lime was added. The 

 russet caused by the micronized sulfur-lead arsenate mixture was reduced 

 by lime from 10.9 percent to 8.7 percent. 



Magnetic sulfur, 1.8 pounds to 100 gallons, lead arsenate 3 pounds, and 

 1 pound of a commercial preparation of zinc sulfate gave less control of 

 scab on Mcintosh and Greenings, and slightly better control than most 

 sprays on Delicious. Fruit russet was increased by tliis mixture. 



The best scab control on Mcintosh was obtained b\- Kolofog-lead 

 arsenate-lime and by liquid lime-sulfur 2 gallons to 100 gallons in the 

 precover sprays, and in the cover sprays magnetic sulfur 8 pounds, lead 

 arsenate 3 pounds, manganese sulfate 2 ounces, soybean flour ^ ounce 

 and lime 6 pounds. However, the latter treatment caused 23 percent fruit 

 russet, a considerable increase over that produced by the wettable sulfur 

 sprays containing lead arsenate with or without lime. 



Leaf injury, as evidenced by yellow leaves, leaf drop, and the amount 

 of foliage remaining on the trees at the time the apples were picked, was 

 consistently more severe on those trees sprayed with the Kolofog-lead 

 arsenate mixture. The most severe injury was on Delicious, which lost 

 about 25 percent of the leaves, while the Mcintosh and Greening trees 

 lost about 8 percent each. 



2. Copper Dusts for Vegetables. Eighteen brands of commercial prepared 

 copper dusts were tested on cucumbers and muskmelons in the field. The 

 copper content of the dusts varied from 3.15 to 8.8 percent. 



The cucumbers were destroyed by mosaic very earl}^ in the season, in 

 spite of good control of aphids, and no yield records or observations on 

 fungus disease control could be obtained. 



The melons grew well throughout the season and downy mildew did not 

 appear until late. There was no noticeable difference in appearance of the 

 foliage of the plots which were dusted and those which received no treat- 

 ment. There was, however, a considerable difference in yield. The best 

 yields were obtained with Copper Hydro Dust C (copper 8.8 percent, cal- 

 cium arsenate 20 percent); Rohm and Haas Dust No. 4 (copper 5.16 



