These results indicate a 21% greater reduction of insects by 
the 1.6 than by the 0.8 1b. per acre application and show about 38% greater 
mortality in the short grass than in the tall grass. 
Additional sweepings in late September and early October of these 
same areas treated only in august revealed still further declines in the 
insect populations of the two higher dosage areas. However, the lower 
dosage areas showed increases over pre-spray counts indicating that residual 
effects of spraying at these rates of application were of less duration than 
at the higher dosage rates and that population recovery had occurred by 
this time. 
Effects of second Spray ng + Sweepings were made before and after 
this spraying in portions of the 1.6 and 0.8 areas that had not been treated 
in August. The populations in these units showed greater reductions fol- 
lowing spraying than had occurred after the first application. However, 
similar but smaller decreases were observed in the check area during the 
same period and suggest that the lower populations after spraying were in 
part due to a usual seasonal decline, re 
Insect populations decreased still more on those portions of all 
areas that were sprayed twice. As after the first treatment, an indirect 
relationship existed between numbers of insects and dosage. Populations 
in long grass habitats showed greater survival than in short grass. 
13 
