Effect of Chemical and Botanical Insecticides on Mustard Aphid Lipaphis Erysimi (Kalt) and Its Parasite

The experiment was conducted during rabi season of 2011–2012, at the research farm college of Agriculture, R.V.S.K.V.V. Gwalior, (M.P.). mustard variety Pusa Rohini was sown in randomized block design with three replications. Efficiently of chemical and botanical insecticides namely, thiamethoxan 25wg (0.02%), Imidacloprid 17.8SL (0.0178%), Bifenthrin 2.5EC (0.005%), Carbosulfan 25EC (0.037%) and Neem seed karnel exctracts (5%) with their combinations were studied against mustard aphid, Lipaphis erysimi (kalt) and their effect on its parasite natural enemies). Population of aphid and Diaretiella rapae was recorded on 5 terminal twigs (10cm) per 5 randomly selected palnt in each plot at 3, 7 and 15 days after each spray. Population of aphid in all the treated plots renged from 22.5 to 48.8 than untreated plots (75.1) aphids per 10cm twig. Among the two sprays of chemical insecticides, imidacloprid was found most effective followed by bifenthrin, carbosulfan and thiamethoxam. Neem seed kernel extracts was found least effective in comparison to chemical insecticides. Population of natural enemies of mustard aphid Diaretiella rapae (mummified aphids) in all the treated plots ranged from 4.40 to 9.70 than untreated plots (15.31) per 10cm twig. Maximum mummified aphid population was recorded in plots treated with NSKE which was found significantly higher than the population in the plots treated with chemical insecticides, Minimum Diaretiella rapae population was recorded in plots treated with imidacloprid. Imidacloprid was more toxic than other chemical treatments. Seed yield in different treatments significantly varied which ranged from 905.3 Kg/ha. (first sprays of NSKE and second spray of carbosulpan) to 1244 kg/ha (two sprays of imidacloprid) against 777 kg/ha in (untreated plots).