Evaluation of Contact Toxicity and Fumigant Effect of Some Medicinal Plant and Pirimiphos Methyl Powders against Cowpea Bruchid, Callosobruchus maculatus (Fab.) [Coleoptera: Chrysomelidae] in Stored Cowpea Seeds

Abstract

The contact toxicity and fumigant effect of Azadirachta indica A. Juss, Anacardium occidentale (L), Pipper guineense Schum and Thonn seeds powders and Pirimiphos methyl (Actellic) dust were evaluated against cowpea bruchid, Callosobruchus maculatus (Fab.). Contact toxicity assay show that A. indica and P. guineense powders have a comparative effect to synthetic insecticide, Pirimiphos methyl. Both were able to cause 100% mortality of C. maculatus at all tested concentrations (0.1, 0.2, 0.4 and 0.8 g/20 g of cowpea seeds) within 7 days of post treatment. However, in the fumigation assay, none of the plant powders was suitable as a fumigant since A. indica and P. guineense powders could only cause 23.3% and 20% mortality of adult cowpea bruchid respectively after 7 days of application. Pirimiphos methyl powder was good as a fumigant causing 100% mortality of C. maculatus after 7 days of application at all tested concentrations.