-Assays were conducted to compare direct and residual contact and oral toxicities to honey bees of sweet corn insecticides and of Bt-sweet corn. Direct contact assays focusing on LC 50 determined that technical grade clothianidin was most toxic, > carbofuran, > imidacloprid = spinosad, > lambda-cyhalothrin, > Bacillus thuringiensis. In residual contact assays, forager age bees were exposed to treated non-transgenic sweet corn tassels. Carbofuran treated tassels caused significant mortality up to 2 and 3 days after treatment (DAT) in

Three field strains of DDT-resistant codling moths from differ ent areas in northern California were mass reared in the laboratory. The degree of DDT resistance in both larvae and adults was deter mined by using two methods of exposure to the insecticides. Topical applications (LD 50 ) were made to the moths, and the cage technique (LC 50 ) was used for the larvae. A DDT-susceptible labora tory strain of codling moth was used as the standard for comparison.The tests showed that all three of the field strains were resist ant to DDT, but further tests showed no cross-resistance to either the carbamate or phosphate insecticides tested.

ABSTRACT. Small plot field trials were conducted in 2002 and 2003 to compare European corn borer (ECB) (Ostrinia nubilalis Hübner) control