Critical periods of soil pest damage to groundnut in intercropped groundnut / sorghum in northern Nigeria

Control of groundnut soil pests is seldom undertaken by resource-poor farmers in Nigeria, mainly due to ignorance of the appropriate control methods or lack of financial resources to purchase the necessary pesticides. In order to recommend to farmers appropriate control periods for the major soil pests of groundnuts and thus minimize cost, field trials were set up in farmers' fields at two sites in the Sudan savanna zone of northern Nigeria in 1996 and 1997 to monitor soil pests. Results showed that the major soil pests were termites, whitegrubs and millipedes. Termite attack on groundnut increased with plant maturity whereas whitegrub and millipede attacks were most critical at the early growth and pod formation stages, respectively. Therefore, resource-poor groundnut farmers in termite- or millipede-endemic areas may achieve some degree of control by applying pesticides at pegging to guard against the critical period of attack on soft or mature pods. In areas where groundnut is more prone to whitegrub attack, pesticide application will be most effective at the early stage of plant growth. Where all three groups of pests threaten groundnut production, a minimum of two pesticide applications, one at early plant growth and the second at pegging, is suggested.