EVALUATION OF SOME PLANT MATERIALS ON THE CONTROL OF CALLOSOBRUCHUSMACULATUS(F) (COLEOPTERA: CHRYSOMELIDAE) IN STORED BAMBARA GROUNDNUT(VIGNASUBTERRANEA (L.) VERDC.)

ABSTRACT This study investigated the insecticidal efficacy of three botanical powders; Azadirachtaindica (neem), Ocimumgratissimum (scent leaf), and Capsicum spp. (pepper) against the cowpea weevil, Callosobruchusmaculatus, a major pest of stored Bambara groundnut and cowpea grains. The experiment was conducted at the Agronomy Laboratory, Department of Agricultural Technology, Federal Polytechnic Bauchi, using a Completely Randomized Design (CRD) with four treatments and three replications. Parameters measured included adult mortality rate, percentage weight loss, number of holes per grain, and seed damage percentage after eight weeks of storage. Results revealed that all plant powders exhibited significant (p < 0.05) insecticidal effects compared to the untreated control. Neem leaf powder recorded the highest mortality rate (97%) and the lowest seed damage (6.80%), followed by scent leaf powder (88.5% mortality; 9.25% damage), while pepper powder showed moderate efficacy (78% mortality; 14.65% damage). The control had the lowest mortality (30.5%) and the highest grain damage (18.90%). Analysis of variance (ANOVA) confirmed significant treatment effects across all parameters, with neem and scent leaf performing best in reducing infestation and post-harvest losses. The study concluded that neem and scent leaf powders possess potent insecticidal and repellent properties, making them viable eco-friendly alternatives to synthetic pesticides. The findings support the promotion of plant-based pest control methods for smallholder farmers to ensure food safety, environmental protection, and sustainable grain storage.