Pest management in cowpea. Part 1. Influence of planting time and plant density on cowpea field pests infestation in eastern Uganda

Insect pests are the main constraint to cowpea (Vigna unguiculata (L.) Walp ) production in eastern Uganda, sometimes causing total crop failure. This study investigated the influence of different times of planting and plant d ensities on field insect pests infestations on cowpea. On-farm trials were established in eastern Uganda at 3 sites for 3 consecutive seasons. Four pl ant densities, i.e., 30 x 20 cm(2), 60 x 20 cm(2), 90 x 20 cm(2) and 120 x 20 cm(2) (subplots) were imposed on three main plots, i.e. planting at on-s et of rains and, 3 and 6 weeks later. Early planting reduced infestation of aphids, thrips and pod bugs but not of Maruca. High plant density also low ered aphid population. A combination of early planting and high plant densi ty gave the best yields. The results indicated that aphids are amenable to cultural control and that complementary management strategies are needed to control other pests of cowpeas. (C) 2000 Elsevier Science Ltd. All rights reserved.