Toxicity of insecticides to cabbage aphid, Brevicoryne brassicae L

Abstract The toxicities of fenvalerate, per‐methrin, methamidophos, and carbaryl to cabbage aphids were determined in laboratory tests using a leaf disc residue method at 15 and 25°C. The order of chemical toxicity was: fenvalerate > permethrin > methamidophos > carbaryl. Fenvalerate and methamidophos exhibited negative temperature coefficients of toxicity, permethrin was equi‐toxic at the 2 temperatures, and carbaryl had a positive temperature coefficient of toxicity. In a field trial, methamidophos reduced cabbage aphid populations to the lowest levels, pyrethroids were initially as effective but carbaryl induced an outbreak of aphids.