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TThile four of the many organic compounds tested in 1941 gave the 
highest reductions in corn borer populations, none of them provided 
such satisfactory protection to the corn plants as did derris. — Questel 
and coworkers (485) • 
Derris (4 percent of rotenone) and synthetic cryolite, each used 
with a spreader, increased the percentage of uninfested ears in Ontario, 
The cryolite sprays considerably reduced the number of ears, and caused 
foliage injury, while derris did not* Five applications of derris were 
the most profitable of all, and two applications of derris were more 
profitable than five of cryolite.— Stirrett (572 ) ; Stirrett and Thompson 
(573). 
In Connecticut a 1-percent rotenone dust produced about 50 per- 
cent of borer- free ears, and dual-fixed nicotine (3.75 percent of nico- 
tine) 66 to 75 percent. The use of derris, cube, or timbo (4 peroent of 
rotenone) in sprays provided control as satisfactory as that of dual-fixed 
nicotine dust. The cost of spraying was somewhat less than that of dust- 
ing. A knapsack bellows duster was better than machine treatment of 
sweet corn. Encouraging results were given by spraying the ears alone 
with 1 pound of derris (4.7 peroent of rotenone) and 2 ounces of Ultra- 
wet spreader in 25 gallons of water when young shoots had formed just 
prior to silking, and later when the ears were in full silk. In spite 
of the lower cost per acre for rotenone dust, the dual-fixed nicotine 
dust was distinctly preferable.— Turner (598 , 600) • 
Good control of the corn borer can be obtained with 0.5 percent 
rotenone dusts, if carefully and thoroughly mixed and applied at the 
rate of 45 to 50 pounds per aore per application.— Baker and coworkers 
(32). 
Comparisons of pure ground derris and cube roots suspended in water 
and applied with and without spreading agents showed no consistent dif- 
ferences. Dual-fixed nicotine dust (4 percent of nicotine) was con- 
sistently more effective than 1 percent rotenone dusts. Dusts made by 
impregnating inert materials with extracts of derris were not significant- 
ly less effective than dusts made by diluting ground derris root.— 
Beard and Turner (42 ) ; Turner (601 ) • 
In Massachusetts the percentages of uninjured ears in untreated plots, 
and in plots treated with sprays of derris or fixed nicotine and dusts of 
derris or dual-fixed nicotine, were 92.9, 99.4, 97.1, 99.4, and 98.8, re- 
spectively.- Bourne and Miitcomb (76) • 
In New York the most satisfactory control measure available for the 
European corn borer in 1942 was four applications, at 5-day intervals, of 
