Toxicity of Malathion and Parathion to Predators of the English Grain Aphid

The LD50 and/or LC50 values of malathion and parathion for the English grain aphid, Macrosiphum avenae (F.), and the dominant insect predators in South Dakota (adults and larvae of the convergent lady beetle, Hippodamia covergens Cuerin-Meneville; adults and nymphs of Nabis americoferus Carayon, larvae of Chrysopa Cornea Stephens) indicated that all predators, in general, were less vulnerable to the insecticides than the aphid. The potential for an integrated program to control cereal aphids with selected doses of malathion or parathion thus appears promising.