Yellow oleander (Thevetia neriifolia juss.) a bio-antifeedant for epilachna beetle (Henosepilachna vigintioctopunctata L.)

Abstract

Fresh and dried leaves and seeds of Thevetia neriifolia Juss. were evaluated for their antifeedant activity against Henosepilachna vigintioctopunctata L. using acetone, benzene, ethanol, hexane, methanol and water as extractants. Based on the percentage of leaf protection, seed extracts were found superior to the leaf extracts. Fresh and dried leaf extracts were on par. Among the solvents, ethanol and methanol gave maximum leaf protection closely followed by water. Based on larval starvation, seed extracts were superior to leaf extracts and fresh leaf extracts were significantly better than dried leaf extracts. Soaking of oowdered plant material in solvents for 48 h and filtration was found as effective as soxhlet method for extracting antifeedant components from leaves and seeds of T. neriifolia.