Studies were carried out to compare the efficacy of insecticide schedules based on calendar intervals with those based on plant growth stages for the control of cowpea insect pests. Spray schedules based on calendar intervals and plant growth stage gave reasonable control of the pest complex and increased grain yields significantly. However, spray schedules based on plant growth stages alone were more efficient for two of the three cowpea varieties tested. This was attributed to differences in maturity periods which made spraying by regular calendar intervals slightly out of phase with attack by key insect pests. Thus, spray schedules based on plant growth stages are recommended for the control of insect pests of cowpea.

An experiment was undertaken at two locations in Nigeria to identify the major insect pests of cowpea, assess the yield losses caused by them and recommend profitable control packages. Various combinations of insecticidal applications were tested at four crop growth stages, in conjunction with varieties possessing moderate levels of resistance to one or two insect pests. Flower thrips were the most important pests, followed by pod sucking bugs and foliage pests. The resistance levels of the varieties did not contribute much to reducing yield losses. Yield losses of upto 75% were caused by insects attacking cowpea during the flower bud and flowering stages, and of 23% by insects attacking during pod development. Insects attacking during the foliage growth stage had little effect on yields. Profitable spray schedules which increased yields by about 50–200% were: three sprays at flower budding, flowering and podding (the optimum), the sprays at either flower budding and flowering or flower budding and podding depending on the location, and one spray at either flower budding or flowering stage. Other spray combinations were also viable, but less profitable. Appropriate recommendations for various categories of farmers are given.