EFFICACY OF THREE NON EDIBLE OILS AGAINST EPILACHNA BEETLE (EPILACHNA DODECASTIGMA WIED.) (COLEOPTERA: COCCINELLIDAE)

Abstract

The study was conducted to evaluated the efficacy of three non edible oils namely, neem, pithraj and karanja in acetone solvent for their toxicity and antifeedant activity against Epilachna dodecastigma Wied. (Coleoptera: Coccinellidae) in the laboratory of the Department of Entomology, HSTU, during March to November, 2017. Four doses viz. 100, 75, 50 and 25 mg/ml along with control was used for mortality of third instar larva and 250, 200, 150 and 100 mg/ml along with a control for adult epilachna beetle. The doses of 100, 75, 50 and 25 mg/ml along with control were also used to determine the antifeedant activity of both third instar larva and adult. The results revealed that all the tested oils had toxic and antifeedant activity against epilachna beetle but pithraj oil was foud the most toxic as compared to others. The mortality and antifeedant activity of three oils and doses with hour after treatments were statistically different. In third instar larva, pithraj oil showed the highest mortality (84.69%) in maximum dose (100 mg/ml) whereas neem oil showed the lowest mortality (24.82%) in minimum dose (25 mg/ml). Similarly, pithraj oil showed the highest mortality (76.67%) in maximum dose (250 mg/ml) and neem oil showed the lowest average mortality (14.33%) in minimum dose (100 mg/ml) against adult beetle. The order of the toxicity of the oils were found as pithraj > karanja > neem. Mortality percentages were also found directly proportional to the hour after treatments. The mortality was found as dose dependent where highest mortality was observed in maximum doses while the lowest in minimum dose in both the larva and adult. The highest antifeedant index was found in pithraj (93.19%) and the lowest in neem (68.81%) against third instar larva. On the other hand, the karanja oil provided the highest antifeedant index (77.99%) while pithraj oil showed the lowest index (62.65%) in adult beetle.