Insecticidal activity of leaf powders against rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae)

AbstractIn laboratory studies leaf powders of ten plants, namely, Ageratum conyzoides L., Chromolaena odorata (Asteraceae) Lantana camara L., Vitex negundo L. (Verbenaceae), Piper nigrum L., Piper longum Linn (Piperaceae), Ricinus communis L. (Euphorbiaceae), Azadiracta indica L. (Meliaceae), Mangifera indica L. (Anacardiaceae), Annona squamosa Linn. (Annonaceae) were evaluated for their efficacy to cause mortality, reduction in progeny emergence and repellency against rice weevil, Sitophilus oryzae L (Coleoptera: Curculionidae). Adult weevils were exposed to three concentrations (1, 5 and 10%) of each plant powder. Observations for contact toxicity were recorded upto 7 days after treatment at 24 hours interval. Highest mortality was recorded from leaf powders of P. nigrum and P. longum at 7 DAT. Lowest emergence of S. oryzae adults were documented from A. conyzoides, A. indica, L. camara in all concentrations tested whereas leaf powders of A. reticulata, A. indica and P. longum effected more repellence towards S. oryzae adults at 24 HAT.