Experiments were conducted in the Biology Laboratory of the Department of Biology, Umaru Musa Yar’adua University (UMYU), Katsina, to evaluate the insecticidal potentials of leaf powders of Jatropha curcas (L) and Euphorbia balsamifera (L) against Callosobruchus maculatus Fab. The test insects were reared in glass jars and tested on whole cowpea grains. Different rates of 0.5, 1.0 and 2.0 g of the leaf powders, and 0.12 g of Permethrin, were applied to 20 g of cowpea seeds in petri dishes separately, while no treatment was added to the control. The petri dishes were arranged in a completely randomized design (CRD) and replicated four times. Adult mortality, weight loss and seed viability were assessed. Effects of the two plant powders was observed to be dosage dependant with the highest (100%) mortality in the higher amounts of both of the powders of E. balsamifera and J. curcas. Both of the leaf powders applied, significantly (P<0.05) reduced survival period of the adult weevils. The leaf powders applied were also found to protect the cowpea seeds against weight loss that might be caused by C. maculatus. Dose of 2.0 g of J. curcas resulted in no (0.00%) weight loss of the cowpea seeds. The germination capacity was not affected by the leaf powders applied. The results obtained in this study indicated that J. curcas and E. balsamifera had potentials of reducing C. maculatus infestation on cowpea seeds.
