Effect of Rice Husk Ash and Neem Extracts on Callosobruchus maculatus in Stored Cowpea in Northern Ghana

Food storage is a positive step towards food security, especially in periods in the year where production is low. There are various improved grain storage methods including the use of synthetic chemicals, although they are associated with other problems such as residual effects in the products. As a result, different ecofriendly methods have been used with mixed results. One such promising method is the use of biopesticides extracted from plants. Following from the success of biopesticide use for pest management, we assessed the effect of rice husk and neem extracts on mortality and re-emergence of Callosobruchus maculatus in stored cowpea seeds and determined their effects on grain quality and weight in a bid to minimize synthetic chemical use in seed storage houses. We conducted this study using rice husk ash and sun- and shade-dried neem seed powder under two different controls. The cowpea seeds were infested with C. maculatus under laboratory conditions in a completely randomized design after the seeds were mixed with 50 g of different formulations of botanicals. Our results show that the different formulations had different effects on weevil mortality, with reduced damage and weight loss in seeds and reduced reemergence of C. maculatus 6 weeks after the experiment. We concluded that our experiment led to reduced seed damage by C. maculatus compared to untreated cowpea and positively affected seed weight. We recommended the use of biopesticides as a cost-effective and environmentally friendly storage option for cowpea, especially in places of high production in the world.