Each of three insecticides—lindane, carbaryl, chlorpyrifos—was tested by topical application on the western pine beetle, Dendroctonus brevicomis LeConte, and two native coleopterous predators, Enoclerus lecontei (Wolc.) and Temnochila chlorodia (Mann.), to assess comparative toxicity. Lindane was more toxic to the predators than to western pine beetle, while carbaryl was relatively non-toxic to E. lecontei when compared with either T. chlorodia or western pine beetle. Chlorpyrifos was equally toxic to all three species. Results of topical application serve to estimate relative effects of insecticides on predacious associates in the western pine beetle community.