Maruca vitrata is a major pest of cowpea, resulting in 20 to 80 percent yield losses in West Africa. A pheromone lure and suitable trap developed in Benin and Ghana has successfully trapped male moths. From these trappings a threshold has been calculated to provide farmers with the optimum time for spraying in conjunction with locally available pesticides and botanical pesticides. The traps have not been as effective in Nigeria and Burkina Faso, suggesting the influence of ecological issues.