INSECTICIDAL ACTIVITY OF TWENTY PLANT POWDERS ON MORTALITY, ADULT EMERGENCE OF SITOPHILUS ORYZAE L. AND GRAIN WEIGHT LOSS IN PADDY

Abstract

ABSTRACT Laboratory studies were conducted to study the effect of twenty plant powders (2 per cent) against rice weevil, Sitophilus oryzae L (Colepotera: Curculionidae) infesting paddy grains. Among them Vitex negundo L. (Verbenaceae) was found to be significantly the best compared to other treatments. At two days after the treatment highest mortality was registered in Nelumbium speciosum Wild (Verbenaceae) (59.9%) followed by Alpinia officinarum Hance (Zingiberaceae) (49.9%), Azadirachta indica A.Juss (42.2%) and by Glorisa superpa L. (Liliaceae) (30.8%). At 7 days after the treatment, 99.1 per cent mortality was recorded in V. negundo followed by A. officinarum (96.6%), N. speciosum (94.4%) and in untreated control, 46.6 per cent mortality was observed. In another experiment, minimum adult emergence was registered in A. indica (18.00), A. officinarum (18.00), G. superpa (20.00), when compared to 98.00 adult weevils in untreated control. At 45th day after treatment grain weight loss was minimum (10.58%) in A. indica compared to untreated control (39.21%). At 60th days after treatment grain weight loss was minimum (13.01%) in A. indica compared to untreated control (49.22 %). At 90th day after treatment lowest grain weight loss was observed in A. indica (18.55%) and highest grain weight loss was seen in C. halicacabum (40.80%).