Bioefficacy Of Neem Oil Formulation With Hydnocarpus Alpina Leaf Extract Against Spodoptera Litura

In a laboratory experiment, pesticidal effect of hexane, chloroform and ethyl acetate extracts of Hydnocarpus alpina Wt. (Flacourtiaceae) leaves was evaluated against Asian army worm Spodoptera litura Fab. at different concentrations viz., 0.625, 1.25, 2.50 and 5.00 per cent. Feeding inhibitory and insecticidal activities were determined by leaf disc method. Among the tested extracts, ethyl acetate extract of H. alpina showed maximum antifeedant (72.2%) and larvicidal (66.6%) activities at 5 per cent concentration. Ethyl acetate extract was subjected to fractionation using hexane, ethyl acetate, acetone and methanol solvents by column chromatography and thin layer chromatography. Ten fractions were obtained and were further screened at four different concentrations viz., 125, 250, 500 and 1000 ppm. Among the tested fractions, the eighth fraction showed maximum antifeedant (68.5%) and insecticidal (62.5%) activities at 1000 ppm concentration. Phytochemical analysis of this fraction showed that it contained flavonoids, phenols and triterpenoids. An oil formulation of the eighth fraction with neem oil recorded 78.6 per cent antifeedant and 82.4 per cent larvicidal activities at 100 ppm concentration, which was superior over individual fraction and neem oil treatments.