Bio efficacy of Ocimum sanctum L. (Lamiaceae) leaf extracts against Pulse beetle (Callosobruchus chinensis L.) (Coleoptera: Bruchidae) in stored green gram (Vigna radiate L.)

Abstract

A laboratory experiment was conducted in the laboratory of Plant Physiology, Department of Entomology, Assam Agricultural University, Jorhat during the year 2014, October to April, 2015 to evaluate the efficacy of Ocimum sanctum L. against Callosobruchus chinensis L. (Coleoptera: Bruchidae). Plants were extracted with petroleum ether, methanol, ethanol and water by using Soxhlet apparatus and tested against adult of C. chinensis. The leaf extract of O. sanctum were evaluated for their adult mortality, oviposition deterrence and adult emergence of C. chinensis. The results revealed that, among the solvent extracts petroleum ether was found to be significantly superior over rest of the solvent extracts, registered the highest percent of mortality (84%) at 5% conc. after 96 hour of treatment followed by methanol (82%), ethanol (80%) and water extract (76%) respectively. Highest oviposition deterrence was found in petroleum ether extract (60.75%), followed by methanol (59.38%), ethanol (56.22%) and water extract (50.11%) respectively at 5% conc. after 7days of seed treatment. In terms of inhibition rate, petroleum ether extract at 5% conc. was found to be most effective (77.29%), followed by methanol (76.65%), ethanol (74.78%) and water extract (74.42%) respectively from 1st day to 10th days of adult emergence.