Cow Horn Ash as a Grain Protectant: A Comprehensive Review of Eco-Friendly Alternatives for Maize Weevil Management

Maize (Zea mays L.) is a staple food in sub-Saharan Africa but suffers major postharvest losses, mainly from the maize weevil, Sitophilus zeamais. Reliance on synthetic insecticides such as organophosphates, carbamates, pyrethroids, and fumigants has reduced pest damage but raised concerns about resistance, food safety, environmental contamination, and rising costs. These drawbacks have spurred interest in eco-friendly alternatives, including botanicals, mineral dusts, and animal by-products. Cow horn ash (CHA), derived from abattoir waste, has emerged as a promising option. Rich in calcium oxide and other minerals, it acts through abrasion, desiccation, alkaline toxicity, and reproductive suppression. Labouratory studies report over 80% adult mortality at higher dosages, reduced progeny emergence, and no negative effect on seed germination. Compared with diatomaceous earth, plant ashes, and botanicals, CHA is affordable, locally available, and safe, though its efficacy declines after 6–9 weeks and preparation lacks standardization. Beyond pest control, CHA reduces food insecurity, lowers pesticide reliance, and converts livestock waste into a valuable resource. Addressing research gaps in formulation, persistence, and field validation will be key to integrating CHA into sustainable postharvest pest management systems.