Residual toxicities of three insecticides to four species (Coleoptera: Carabidae) of arthropod predator

In laboratory bioassays, four carabid species [Agonum dorsale (Pontoppidan), Bembidion lampros (Herbst), B. obtusum Serville, and Demetrias atricapillus (L.)] that are important predators of aphids in cereals in the United Kingdom were exposed to deposits of deltamethrin, dimethoate, or pirimicarb on glass for up to 72 h. We detected differences between compounds and species that are discussed in the context of exposure of these predators to insecticides in the field. We also describe problems involved in obtaining comparative toxicity data when dilutions of field application rates for target species are used in bioassays with nontarget species. Such problems add another dimension to risk assessment based on laboratory data.