Morphological abnormalities induced by plant extracts on development stages of Spodoptera litura

Abstract

The present work was intended to evaluate the Morphological abnormalities induced by plant extracts on development stages of Spodoptera litura which develops on cabbage plant. Second instar larvae of S. litura were treated with the leaf and seed extracts of Azadirachta indica, Catharanthus roseus and Ocimum sanctum at the concentrations of 0.01, 0.05, 0.1, 0.5% and their development was observed till the emergence of adults. Larvae were observed daily and data pertaining to any morphological abnormality induced in developing larvae, pupae and emerging adults was recorded. Larval body became dark and spotted loosing its usual characteristic pattern. It became thin and stretched and was ruptured at various regions of larval body. Most of the abnormalities were due to abortive moultings. Adult emerged from treated larvae showed several deformaties like short body, deformed wings, legs, mouth parts and genitalia. Strong growth regulating effect was shown by A. indica and C. roseus. The growth was significantly retarded at all the concentrations however at higher concentrations development was abnormally prolonged. O. sanctum showed very little growth disrupting property.