Toxaphene, Methyl Parathion, and Fenvalerate Disappearance from Cotton Foliage in the Mid‐South

Abstract

Abstract Insecticide foliar‐persistence data are needed for the development and refinement of predictive models concerning pesticide loss from agricultural ecosystems. Toxaphene (chlorinated camphene), methyl parathion [ O,O ‐dimethyl O ‐( p ‐nitrophenyl) phosphorothioate], and fenvalerate [( RS )‐ α ‐cyano‐3‐phenoxybenzyl ( RS )‐2‐(4‐chlorophenyl)‐3‐methylbutyrate] were field‐applied by ground equipment to mature cotton ( Gossypium hirsutum L.) in northern Mississippi at rates of 2.30, 1.15, and 0.11 kg ha −1 , respectively. Pesticide loads on the plants were measured periodically for 146 h following application. Air temperature, windspeed, and relative humidity were also measured during the study. About 92, 76, and 66% of the applied toxaphene, methyl parathion, and fenvalerate, respectively, were intercepted by the cotton plants. The calculated 50% disappearance times for toxaphene, methyl parathion, and fenvalerate were 17.6, 2.4, and 79.4 h, respectively.