Timing insecticide sprays for control of pod-sucking bugs (Pentatomidae, Coreidae, and Alydidae) in cowpea (Vigna unguiculata [L.] Walpers)

Field experiments were conducted at Charleston, South Carolina, during 1997 and 1998 using foliar applications of endosulfan to evaluate damage by pod -sucking bugs (Pentatomidae, Coreidae and Alydidae) to cowpea at different pod-fill stages. Also, seasonal dynamics of bugs were assessed in untreated cowpea. Cowpea pod and seed damage was significantly lower in most plots t reated with endosulfan than in untreated plots. Damage by sucking bug pests in 1997 was generally lower in treatment combinations that included sprayi ng at early pod-fill. In 1998, pod damage was lower when treatments were ma de at early pod-fill than at late pod-fill. Also, seed damage in plots trea ted at late pod-fill was the same as that from the untreated check. However , treatment at early pod-fill gave a significantly lower seed damage than t he control. Total seed yield was higher from plots with treatment combinati ons that included early pod-fill compared to untreated plots in 1998. Build up of pod-sucking bugs, composed of Nezara uiridula (L.), Leptoglossus phyl lopus (L.), and the congeneric species Alydus eurinus (Say) and A. pilosulu s Herrich-Schaeffer, started during the late vegetative stage. Bug populati ons peaked around late pod-fill and declined near dry-pod harvest. Nezara v iridula was the first and most abundant species of pod-sucking bug to infes t the crop. Populations of the other bugs, particularly A. eurinus and A. p ilosulus, occurred toward late pod-fill. Our results suggest that early pod -fill is the most susceptible stage of cowpea to damage by pod-sucking bugs and that N. viridula is the major pest.