Effects of crushed fresh Cleome viscosa L. (Capparaceae) plants on the cowpea storage pest, Callosobruchus maculatus Fab. (Coleoptera: Bruchidae)

Abstract

Laboratory assays were carried out to evaluate the effects of fresh Cleome viscosa on the reproduction and survival of Callosobruchus maculatus. Significant control was achieved by the two treatments with the highest quantity of crushed leaf. Fresh crushed C. viscosa also led to complete inhibition of embryonic development of eggs exposed for 48h in all botanical treatments. On-farm storage trials, using 5, 15 and 25 g C. viscosa crushed plant per 1 kg of cowpeas, showed a dose-dependent reduction in bruchid numbers of 35.4, 59.5 and 86.4%, respectively, after 120 days of storage. Moreover, the pea losses were relatively low (≤11%) and pea germination was unaffected (>80%) in all batches where C. viscosa was introduced. Our results indicate that C. viscosa has significant potential for controlling the pest. The conditions for optimal use of the plant in stored cowpea management are discussed.

Keywords:

• botanical insecticide
• Callosobruchus maculatus
• Cleome viscosa
• cowpea storage

Acknowledgements

Authors are grateful to the Laboratoire Central d'Entomologie Agricole and the INERA staff of the Burkina Faso for facilitating bioassays and on-farm trials and by supporting research on leguminous crops. Dr Manuel Tamo at IITA-Benin station is thanked for his help in producing the English version.