Interaction between pod age and position on damage to cowpea Vigna unguiculata by hemipteran pod-sucking bugs

Laboratory and screenhouse studies were carried out to assess the relationship between pod age and pod position of cowpea and damage by different pod bug species. The coreids Clavigralla tomentosicollis Stäl and Riptortus dentipes Fabricius caused significant damage to young pods of cultivated genotypes, in contrast to the coreid Anoplocnemis curvipes Fabricius and the pentatomid Aspavia armigera Fabricius which exhibited minor feeding activity. Percent seed damage declined with pod age, the critical stage for pod bug infestation being when pods were about eight days old. Clavigralla tomentosicollis and R. dentipes caused significantly higher damage to pods located within the leaf canopy, thus behaving differently from Anoplocnemis curvipes which showed a distinct preference for pods growing above the leaf canopy. The feeding activity of Aspavia armigera was not affected by the position of pods on the plant. Overall, the study suggests that cowpea genotypes with a short flowering period and pods held above the leaf canopy offer the most promise in the management of pod-sucking pests.