Toxicity of Several Insecticides to Two Species of Beneficial Insects on Cotton1

Laboratory tests conducted at College Station, Texas, indicated that dieldrin was the least toxic material tested against Hippodamia convergens G.-M. by a petri-dish method and was followed in order of increasing toxicity by endrin, BHC, toxaphene- DDT, dieldrin-DDT, heptachlor-DDT, heptachlor, DDT, parathion and methyl parathion. When applied topically, dieldrin was again the least toxic material, followed in order of increasing toxicity by toxaphene, DDT, and endrin. Toxaphene was the least toxic material tested against adult Orius insidiosus (Say) by confining the insects to treated plants for 2 days, and was Followed in order of increasing toxicity by DDT, dieldrin, heptachlor, aldrin, malathion, methyl parathion, and parathion. Toxaphene-DDT was the least toxic of the five insecticide mixtures tested.