Residual Foliar Toxicity of 4"-Epi-Methylamino-4"- Deoxyavermectin B1 Hydrochloride (MK-243) and Selected Commercial Insecticides to Adult Hymenopterous Parasites, Pteromalus puparum (Hymenoptera: Pteromalidae) and Cotesia orobenae (Hymenoptera: Braconidae)

Abstract

The residual contact toxicity of MK-243 (4-epi-methylamino-4-deoxyavermectin B1 hydrochloride), permethrin, esfenvalerate (pyrethroids) and methomyl (carbamate) to 2 parasitic hymenoptera, Cotesia orobenae (L.) (Braconidae) and Pteromalus puparum (L.) (Pteromalidae), in broccoli was evaluated. Each parasite was caged on treated broccoli leaves at various times after the plants had been sprayed in the field. Methornyl was the only insecticide consistently toxic to P. puparum up to 1 d after the leaves were sprayed, but this compound had no affect 3 d after treatment. MK-243 and the 2 pyrethroids had no significant effect on P. puparum . The effect of the insecticides on C. orobenae was different and less consistent. Esfenvalerate caused significant mortality of C. orobenae , but methomyl and permethrin killed a significant number of parasites in only 1 of the 2 trials. MK-243 was not toxic to C. orobenae in our studies.