Laboratory Evaluation of Several New Insecticides for Control of the Pale Western Cutworm1

Abstract

Fifty-six insectiicdes were evaluated in the laboratory for control of larvae of Agrotis olthogonia Morrison. Endrin was used as the reference standard for the selection of alternates to the organochlorine insecticides. Initial screening tests readily selected possible alternates and indicated that larvae of this species detoxified the carbamate insecticides. American Cyanamid 47031 (cyclic ethylene (diethoxyphosphinyl) dithioimidocarbonate) ; AC-47470 (cyclic propylene (diethoxyphosphinyl) dithioimidocarbonate); Bayer 78182 ( O, O -diethyl phosphorothioate, O -ester with ( O -chlorophenyl) glyoxylonitrile oxime); Dursban®; ( O, O -diethyl O -3,5,6-trichloro-2-pyridyl phosphorothioate); and trichlorfon were comparable to isobenzan as oral toxic ants but 2–3 times less toxic than endrin. LD50 and LD95 values were determined for 15 selected compounds to establish comparative oral toxicity levels and baseline toxicity data for larvae of the pale western cutworm. Greenhouse tests indicated that Dursban and AC-47031 at 6 oz per acre (0.42 kg per hectare) gave control comparable to endrin at 4 oz per acre (0.2H kg per hectare) and that trichlorfon was unsatisfactory as a soil treatment. Other insecticides, as indicated by these tests, are worthy of field-trial evaluation for control of this species.