Abstract

The present study indicates that leaf powder extract of Vinca rosea L. 5.0 and 2.5 per cent were highly effective in reducing the food consumption, larval body weight and faecal matter voided by Pericallia ricini under laboratory conditions. Caterpillars consumed very less amount of castor leaves treated with V. rosea leaf powder extracts 2.5 and 5.0 per cent (i.e. 0.444 and 0.263g, respectively) compared to untreated control. The consumption was 0.483g per four caterpillars in the castor leaves treated with neem leaf powder extract 5.0 per cent. Larvae fed by V. rosea 5.0 per cent, neem leaf powder 5.0 per cent and V. rosea leaf powder 2 .50 per cent treated leaves voided 0.430, 0.497 and 0.627 g of faecal matter per four caterpillars, respectively. Larval body weight was decreased to 80.63 per cent in V. rosea 5.0 per cent over untreated check. It was followed by V. rosea 2.5 per cent and neem 5.0 per cent and registered 71.26 per cent decrease in body weight over the untreated check. The extracts of V. rosea exhibited feeding inhibition or gustatory repellency or impairment in food assimilation and imbalance in enzyme activity

Keywords: Pericallia ricini, food consumption, body weight, faecal matter, Vinea rosea, neem.