Efficacy and Economics of Some Modern Insecticides against Aphid, Aphis gossypii L. in Cotton

A Field trial were conducted in two crop seasons (kharif) during 2005–06 & 2006–07 to study the comparative bioefficacy of six insecticides, against Cotton Aphid, Aphis gossypii L., using foliar application. A insecticide of Thio-ureas class Difenthiuron 50 SC @ 400 gai/ha was found most effective and its recorded maximum reduction in population of cotton aphid, with maximum increase in yield over control, net profit and was relatively safer for potent predators. However Thiomethoxam 25 WG 75 gai/ha and Imidacloprid 200 SL @ 100 gai/ha were next effective chemicals. In the initial stage of infestation application of Thiomethoxam 25 WG was found to be more economical because of its higher cost: benefit ratio and relatively less toxic to potent natural enemies. Our results suggest that Difenthiuron, Thiomethoxam and Imidacloprid are good substitutes for conventional insecticides in vogue, which could be used in formulating a successful management for A. gossypii in cotton.