Studies on Adsorption of lambda-cyhalothrin-EC on Cotton Mosquito Net

Abstract

The effective management and control of mosquitoes in human living environments especially with treated nets are crucial to minimize vector-borne diseases such as malaria. Pyrethroid, λ-cyhalothrin has been considered a powerful tool in the control of mosquitoes and is therefore incorporated into mosquito net as pesticide, in this study. The adsorptive behavior of the pyrethroid pesticide, λ-cyhalothrin (alpha-cyano-3-phenoxybenzyl-3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-dimethyl-cyclopropanecarboxylate) in aqueous solution on cotton fabrics at different treatment times, temperatures, and concentrations are presented in this study. The results show that the Type I isotherm model provides the most favourable description of the adsorption of LCT-EC on the cotton fabrics. λ-cyhalothrin concentrations of 0.10, 0.15 and 0.20 mg in 50 ml distilled water have been found to be adequate for domestication of the adsorption process to treat virgin mosquito nets at 40⁰C. A warm solution (40 – 50⁰C) of λ-cyhalothrin (LCT-EC) containing 0.10, 0.15 or 0.20mg LCT-EC in distilled water is therefore recommended for treating a 100sq.cm of new mosquito net. The recommended soaking time for efficient adsorption is between 40 – 50 minutes. The nets can be re-impregnated with the pesticides after every six washes because the functions on the nets are not durable to laundering and storage.