Potency of some indigenous plant powders against Callosobruchus chinensis (L.) infesting rice bean seeds

Nine different plants powders viz., rhizome of Costus speciosus Koen ex retz., leaf of Diospyros lanceafolia Roxb., seed coat of Diospyros lanceafolia Roxb., leaf of Juglans regia Linn., seed of Litsea citrata Bl., leaf of Ocimum sanctum Linn., seed of Piper nigrum, leaf of Zanthoxylum oxyphyllum Edgw. and seed coat of Zanthoxylum oxyphyllum Edgw. @ 5% w/w were evaluated as grain protectants against Callosobruchus chinensis (L.) on rice bean seeds. Based on the parameters like oviposition, adult emergence, seed infestation and weight loss, L. citrata was observed the most effective up to 2 months of storage. It was closely followed by P. nigrum, D. lanceafolia and J. regia, while Z. oxyphyllum and C. speciosus were least effective. These powders had no adverse effect on seed germinability. L. citrata and P. nigrum could reduce egg laying and adult emergence by 63.14 to 66.16% and 50.49 to 59.50%, respectively.