Toxicological Studies on Cutworms. VII. Microplot Field Experiments on the Effectiveness of Four Experimental Insecticides Applied as Rye Cover Crop and Soil Treatments for Control of the Dark-Sided Cutworm12

Abstract

Microplot field trials were conducted to assess effectiveness of 4 insecticides applied to the rye cover crop and to soil against the larva of Euxoa messoria (Harris), which allacks flue-cured tobacco in southwestern Ontario. Under adverse conditions of moderately high temperature and low soil moisture, Dursban® ( O, O -diethyl O -(3,5,6-trichloro-2-pyridyl) phosphorothioate) at ½ and Bay 37289 ( O -ethyl O -2,4,5-trichlorophenyl ethylphosphonothioate) at 1 lb active ingredient (AI)/acre as rye treatments provided effective control. Stauffer N-2596 ( S- ( p -chlorophenyl) O -ethyl ethylphosphonodithioate) at ½ and 1 lb AI/acre was slightly less effective, while phoxim at ¼ and ½ lb AI/acre was ineffective. Under optimum conditions of moderate temperature and high soil moisture all 4 materials as incorporated soil treatments at 1-1½ lb AI/acre provided excellent cutworm control. Residue analysis indicated that at the highest rates of application applied to the soil (Dursban and N-2596 at 2 lb, Bay 37289 at 3 lb AI/acre) 94% of the Dursban, 88% of the Bay 37289, and 85% of the N-2596 disappeared from the soil by harvest. No residues were found in fresh tobacco.