Evaluating the Impact of Chilli Powder (Capsicum Frutescens), on the Management of Common Bean Weevils (Acanthoscelides Obtectus)

Post harvest losses resulting from common bean weevil (Acanthoscelides obtectus) remain a major threat to smallholder farmers in Zambia by reducing grain quality, farmer income, and national food security. Although Synthetic pesticides are more effective in controlling the pest, they still present health and environmental risks and more often unaffordable especially for rural households. This study evaluated Chilli powder (Capsicum frutescens) as a potential botanical protectant against (Acanthoscelides obtectus). The study implored a split-plot factorial design with three experimental phases: laboratory bioassays with six treatments replicated 3 times (0g, 2g, 2.5g, 3g 3.5g, and 4g), storage trials, and field validations were conducted to determine lethal concentrations, feeding deterrence, and storage efficacy. Results revealed a clear dose-dependent toxicity, with probit analysis estimating LC?? and LC?? at 2.19 g/100 g and 3.86g/100g, respectively. Chilli treatments significantly reduced adult mortality, grain perforation, weight loss, and infestation rates (p < 0.001), with effectiveness plateauing at 3.0–3.5 g/100 g. Field validation showed that Chilli at 3.5 g/100 g provided grain weight protection comparable to Actellic Super®, and significantly outperformed traditional ash treatments commonly used by farmers. These findings demonstrate that chilli powder is an accessible, eco-friendly, and cost-effective alternative to synthetic insecticides. At optimal doses of 3.0–3.5 g/100 g, Chilli can sustainably reduce post-harvest losses, and its integration with improved storage practices offers strong potential for scaling up as a farmer-friendly pest management strategy in Zambia.