Experiments were conducted to evaluate the efficacy of selected plants extracts of Euphorbia balsamifera L. and Citrus sinensis L. against Callosobruchus maculatus Fab. in the laboratory under the conditions of 28 ± 2°C and 70 ± 5% R.H. The test insects were reared in rearing bottles and tested on whole cowpea seeds for comparison. Different concentrations of 0.5, 1.0, and 2.0 g of the plant extracts were dissolved in 10 ml acetone and applied for mortality, seed damage and germination tests. Total (100%) mortality of adults of C. maculatus was observed after 3.67 to 6.67 days of treatment with the plant extracts. The findings of this study revealed that the plant extracts significantly (P<0.05) reduced cowpea seed weight loss. There was no (0.00%) weight loss of cowpea seeds recorded when higher (2.0 g/10.0 ml acetone) concentration of both extracts was applied. These plant extracts showed significant (P<0.05) effect on the germination capacity of cowpea seeds. The results obtained in this study indicated that extracts from C. sinensis and E. balsamifera had potentially reduced C. maculatus infestation on cowpea seeds. Hence, recommended for the control of C. maculatus attacking cowpea seeds during storage.
