Potentials of Cow Dung Ash as Protectants of Cowpea Seeds against Callosobruchus maculatus F. (Coleoptera: Chrysomelidae)

Abstract

Experiments were conducted to assess the protectant ability of cow dung ash (CDA) to cowpea seeds against Callosobruchus maculatus F. under laboratory conditions of 50-65% R.H and 28-32oC. The CDA at different rates of 0.625, 1.25, 2.50, 5.00, 10.00% (w/w) incorporated with cypermethrin powder at 0.625% were applied to 20 g of cowpea seeds in petri dishes. None of the ashes or cypermethrin was added to the control. Ten beetles were introduced into each of the petri dishes and covered with muslin cloth. The experiment was arranged in a completely randomized design (CRD) and replicated three times. Effects of the treatments on adult mortalities as well as median lethal dose (LD50) of CDA against C. maculatus were determined. Adult emergence and weight losses in seeds treated with CDA at different doses were assessed. Findings of the study revealed that the adult mortality of C. maculatus among different CDA treatments differed significantly (p < 0.05) and ranged from 13.33 to 100.00% 72 hours after treatment (HAT). Results of the study also showed that LD50 of CDA against C. maculatus at 24 hours after treatment (HAT) was 5.51 % (w/w). No adults emerged from the treated seeds and weight losses were observed in those treated with the lowest dose and the control only. Therefore, CDA could be utilized to protect cowpea seeds from C. maculatus infestations during storage.