Laboratory Bioassays of Insecticides Against the Cabbage Looper

Cabbage looper larvae were tested for response to serial doses of formulated insecticides. Collard leaf discs (5-cm diam) were dipped briefly in the formulations containing 0.25% Valent X-77 surfactant, air dried horizontally and then 2 discs were placed on paper toweling in round plastic dishes (14 cm diam, 1 cm ht). Ten 30-50 mg larvae were introduced in each dish which was then covered with a perforated lid. Larval mortality was recorded at a 4 DAT for microbial insecticides and 2 DAT for other insecticides. Five replications of six serial doses on a total of 300 larvae were used for each product tested. Larvae were obtained from a culture derived from pupae collected each May and June from the check plots in the experimental fields of this study.