Organophosphorus and Carbamate Insecticides as Soil Treatments Against the Eye Gnat, Hippelates collusor, in the Laboratory1

Abstract

Twenty-four organophosphorus compounds, three carbamate insecticides and one chlorinated hydrocarbon insecticide (Thiodan® have been screened in the laboratory as soil treatments against the eye gnat Hippelates collusor (Townsend). (Chemical definitions of proprietary materials are listed below.) Of the organophosphorus compounds, Co-Ral®, Bayer 25141, Experimental Nematocide 18133, Bayer 29493, GC-4072, Ethyl Guthion®, Trithion®, GC-3582, ronnel, G-30494, phorate, Bayer 22408, Methyl Trithion®, GC-3583, ethion, Guthion®, Di- Syston®, and Delnav® manifested a high degree of initial activity against the gnat. The first four compounds in this group had the greatest activity while Di-Syston and Delnav were less effective. Relatively moderate dosages of dimethoate and parathion were required for 90% reduction of the gnats. American Cyanamid Compound 18706, Dylox®, phosphamidon, and dicapthon proved effective only at higher dosages. Thiodan was ineffective at practical dosages. Of the carbamate insecticides, AC-5727 was most efficient in reducing eye-gnat emergence from treated soil. Sevin® was effective, but only when applied in greater quantities, and m-tbutylphenyl N-methylcarbamate did not indicate appreciable activity at the rates used here.