Bioefficacy of Couroupita guianensis (Aubl) against Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae) larvae

With a view to develop an ecofriendly botanical pesticide, we evaluated the bioefficacy of crude extracts of Couroupita guianensis against third instar larvae of Helicoverpa armigera. Maximum feeding deterrency (81.67%) and least LC50 (2.72%) for larval mortality were seen in hexane extract. Hexane extract was subjected to column chromatography using different ratio of hexane-ethyl acetate solvent system. Totally eight fractions were collected. The fractions were screened at 125, 250, 500 and 1,000 mg kg-1 concentrations against H. armigera using no-choice leaf disc method. Fraction eight showed maximum antifeedant (86.24%) and larvicidal (80.88%) activities at 1,000 mg kg-1 concentration. C. guianensis could be utilized in pest control programme