Increasing yield of cowpea by 30–90% is possible in Senegal when the crop is sprayed once or twice in order to control flower thrips. Therefore it appears necessary to determine the action threshold for the dominant species of flower thrips,Megalurothrips sjostedtiTryb. Eight and 22 thrips per 25 flower buds (at Nioro and Bambey respectively) and 150 thrips per 25 flowers were determined as the action threshold where a minimum of two sprays is needed. When only one spray is necessary during the flowering period, 90 thrips per 25 flowers is the suggested action threshold to protect flower buds as well as flowers from thrips attacks.