• Onekutu Amana
  Department of Zoology, Joseph Sarwuan Tarka University, P.M.B. 2373, Benue State, Nigeria
  




• Iboyi Mark Ojonugwa
  Department of Zoology, Joseph Sarwuan Tarka University, P.M.B. 2373, Benue State, Nigeria
  




• Nwannunu Ifeoma Ude
  Department of Zoology, Joseph Sarwuan Tarka University, P.M.B. 2373, Benue State, Nigeria
  

The efficacy of Vernonia amygdalina and Azadirachta indica leaf powder and solvent extract against aspects of the biology of Callosobruchus maculatus (F.) on cowpea seed was evaluated under ambient temperature at the Biological Sciences Laboratory, Joseph Sarwuan Tarka University, Makurdi. Plant leaf powders were obtained by grinding the plant leaves using electric grinder and sieving with appropriate mesh size while leaves extracts were obtained by soaking 200g each of the powdered plant materials separately in 1 liter of methanol, n-hexane and ethyl acetate, filtered and the residue evaporated at 40˚C. The stock was used to prepare the treatments used for the study. Adult Callosobruchus maculatus collected from infested cowpea seeds at market storage site in Makurdi were used to setup an insect culture. Newly emerged bruchids were exposed to different concentrations. The highest adult mortality was recorded in seeds treated with 1g (9.3±0.7) bitter leaf powder (p<0.05).