Effect of Plant Density and Weeding Regime on Population and Severity of Aphids (Aphis craccivora Koch) and Foliage Beetles (Ootheca mutabilis Sahl) on Cowpea in Sierra Leone

Cowpea is one of the major grain legumes grown in Sierra Leone. This trial was conducted in the upland soils of Njala, southern Sierra Leone, in the 2011/2012 cropping season, to determine the effects of plant density and weeding regime on population and severity of aphids and foliage beetles on cowpea. Three plant populations (P1 = 456,522; P2 = 239,130 and P3 = 152,174 plants/ha) and three weeding regimes (no weeding, once at 3 weeks after sowing (WAS) and twice at 3 and 6 WAS) were investigated. The study provides the evidence that- aphids and foliage beetles are better controlled by weeding twice at 3 and 6 WAS, and that planting at lower density (152,174 plants/ha) has the potential to reduce the population of both foliage beetles and aphids. These results have implications for improving cowpea productivity in smallholder farms through the simple manipulation of plant population and weeding regime for the control of aphids and foliage beetles, and probably other cowpea insect pests.