Simulated Natural Encounters of the Insecticides, Chlorpyrifos and Carbaryl, by Western Pine Beetle Predators Enoclerus lecontei and E. sphegeus (Coleoptera: Cleridae)1

Abstract

Laboratory tests are described, using residual film and topical application methods to evaluate the toxicity of aqueous formulations of chlorpyrifos and carbaryl to two coleopterous predators, Enoclerus lecontei and E. sphegeus . The insecticide-impregnated filter paper discs simulated predators walking on sprayed substrates, and topical application evaluated intrinsic susceptibility. Chlorpyrifos was equally toxic to both species in both tests, whereas carbaryl showed very limited toxicity to both species. These tests indicate that carbaryl, a chemical which provides extensive protection of ponderosa pine trees from attack by western pine beetles, has minimal effect on the important predators of the western pine beetle