Trichlorfon residues on pasture

Abstract

Plots of established pasture were treated with a granular formulation of trichlorfon, or with trichlorfon spray. Analyses of pasture sampled after treatment showed that residues of trichlorfon declined rapidly under both winter and summer conditions. Twelve days after treatment, pasture from plots treated with granules at rates of 1, 2 1/2, or 5 lb active ingredient per acre contained 1, 2, and 5 p.p.m. trichlorfon respectively; pasture sampled at the same time after treatment from plots sprayed at rates of 1 or 2 lb active ingredient per acre contained 2 and 5 p.p.m. trichlorfon respectively.