Efficacy of Melochia corchorifolia L. (Sterculiaceae) on feeding behavior of four lepidopteran pests

Abstract

Experiments were carried out to assess the pesticidal effects of solvent extracts of Melochia corchorifolia leaves, their fractions and new oil formulation consisting of neem and karanj oils against four lepidopteran pests viz., Helicoverpa armigera (Hub.), Spodoptera litura (Fab.), Erias vittella (Fab.) and Leucinodes orbonalis (G.) at 1% concentration. Antifeedant activity was determined by leaf disc no-choice method. Ethyl acetate extract of M. corchorifolia exhibited maximum antifeedant activity (54.24%). It was subjected to fractionation using column chromatography. Among thirteen fractions obtained, ninth fraction showed maximum antifeedant activity against all tested insects at 1000 ppm concentration. Phytochemical analysis of ninth fraction showed the presence of steroids and alkaloids. This active fraction was mixed with neem and karanj oils and evaluated against selected lepidopteran pests. Formulations 1 (Fl) (neem+pongam oil+active fraction) showed good antifeedant activity of 63.75, 78.94, 84.69 and 78.96% against H. armigera, S. litura, E. vittella, L. orbonalis, respectively. This plant could be considered to prepare botanical pesticide. © 2012 Academic Journals Inc.