Antifeedant and Insecticidal Activity of Different Solvent Extracts of Vitex negundo (L) against Cotton Leafworm Spodoptera litura (Fab.)

Spodoptera litura, commonly knows as cotton leafworm, is a serious polyphagous pest causing damage to more than 150 species of host plants and it is distributed throughout the tropical and sub- tropical regions of the world including India, Japan, China and South East Asia. The chemical pesticides affect the non- target organisms and human beings, directly or indirectly. To find environmentally safe alternative there is need of considering the pesticides of biological origin to replace synthetic pesticides. Anti-insect activity check of plant extract can play important role in ecofriendly control of insect pest. Spodoptera litura is a dangerous polyphagous pest. The present work aimed to identify a natural alternative to chemical pesticides for the control of insect pests by examining a variety of factors, including larval weight, duration, antifeedant activity, and mortality. Maximum larval mortality (10.30%) was noted in Vitex negundo chloroform extract. The larval duration is much longer in the Vitex negundo chloroform and methanol extracts (10.23 days and 10.56 days, respectively) as compared to the control group. The Vitex negundo chloroform extract (59.42%) andacetone (37.68%) have the strongest antifeedant effects. In comparison to the control, the larval weight was significantly reduced in the Vitex negundo chloroform (0.391 gm), acetone (0.401 gm), and methanol extract (0.420 gm) extracts (0.621 gms).