Efficacy of Chinese Pepper Zanthoxyllum xanthoxyloides (Lam) Watern against the Cowpea Bruchid Callosobruchus maculatus (F) (Coleoptera: Bruchidae)

The efficacy of acetone extract of the Chinese pepper, Zanthoxylum xanthozyloides (Lam) in the bruchids control was investigated under laboratory storage-conditions of 27-30°C, 60-70% RH. Different concentrations of Z. xanthozyloides were applied against the cowpea bruchid, Callosobruchus maculatus (F) (Coleoptera: Bruchidae) at 0.5%, 1.5% and 2.5% (w/v) and 0.0% (control). Results showed that the extract achieved 100% adult mortality at 2.5% concentration within 96 h of treatment. 2.5% (w/v) Z. zanthozyloides reduced larvae development and adult emergence significantly after six weeks of treatment in storage, while control, 0.50 and 1.50% achieved 0.0, 83.11 and 93.25% reduction during the same period. Increase in Weevil Perforations Index of 1.03, 5.04, 12.13 and 50.00 were recorded for beans treated with 2.5%, 1.5%, 0.5% (w/v) and control after 6 weeks of storage, respectively. This study has revealed Z. zanthoxyloides as a potential bio-insecticide applicable in the control of stored products.