Toxicity of Insecticides to Adults and Larvae of Colorado Potato Beetle (Leptinotarsa decemlineata Say)

摘要

Toxicity of insecticides to three stages of Colorado potato beetle (CPB) field population was determined. With exception of cypermetrin, all insecticides were more toxic to 1st generation adults (Al) than to overwintered adults (OA). Similar toxicitywas found to Al and OA for cypermethrin, fenvalerate, phosmet and methidathion. Bensultap and thiocyclam were two times more toxic to Al. Carbosulfan was 6 times, and chlorpyriphos 11 times more toxic to Al than to OA. Toxicity of phosmet was approximately the same for all observed stages. Methidathion was very uniformly toxic to adults and almost nontoxic to larvae (LI). Determined LC_(50) values of fenvalerate, carbosulfan, phosmet, methidathion and ben-sultap for OA, and of phosmet and methidathion for Al and LI were found to be higher to concentration recommended for field application (RFC) indicating decreased susceptibility of these insect stages to insecticides tested.