Integrating Planting Date with Insecticide Spraying Regimes to Manage Insect Pests of Cowpea in North-Eastern Nigeria.

We sought to establish the most effective combination of planting dates with insecticide spraying regimes for the management of insect pests of cowpea in the savannas of northeast Nigeria. The results after 3 sprays, made once each at the bud initiation, flowering, and podding stages, did not differ significantly from those after 2 sprays, made once each at flowering and podding, in terms of reducing in insect pest population and increasing grain yield. Despite the reduction in insect infestation, delaying planting beyond mid-August reduced cowpea grain yield by 12.3%, on average. The yield of the medium-maturing variety IT89KD-391 was significantly higher when planted in mid-August and sprayed twice than when planted on the earlier or later dates. The yield of the indeterminate late-maturing variety ITKD89-288 was higher when planted in early August and sprayed thrice. Early- and medium maturing cowpea varieties should therefore be planted in mid-August and sprayed twice. Late ¼ maturing indeterminate varieties should be planted in early August and sprayed thrice.