Evaluation of Botanical and Synthetic Insecticides for the Management of Cotton Pest Insects

Field trials were carried out to compare the effect of neem (Azadirachta indica A. Juss) oil at 1%, 1.5% and 2% and neem seed water extract at 1%, 2% and 3% concentration with that of synthetic insecticide (Polytrin C (R) 440 EC) against Bemisia tabaci, Amrasca devastans, Thrips tabaci, Earias insulana, Pectinophora gossypiella and Helicoverpa armigera. The treatments were administered four times during the cotton growing season and observation were recorded before one day and after 24, 72, 144, 216 and 288 days of treatment application. Neem oil at 2% and neem seed water extract at 3% significantly reduced the whitefly, jassids and thrips infestation up to 12 days after spray as compared to that in the control. Similar trend in population reduction of sucking insect pests of cotton was observed in other three treatment applications. Synthetic insecticide proved to be more toxic against the test insects than neem based treatments at any interval. Neem derivatives at all concentrations badly affected the attack of Spotted bollworm where as only at higher concentrations adversely affected the attack of pink bollworms up to 12 days after spray. Plots treated with 1.5% and 2% neem oil and 3% neem seed water extract resulted in to significantly higher yield as compared to that in the control. Polytrin C (R) 440 EC in all cases was highly toxic to the test insects as compared to any other treatment.