Sustainable postharvest pest management: toxicological efficacy of locally sourced and formulated bio-pesticides against the larger grain borer (Prostephanus truncatus) on traditional maize grain storage facilities to small-scale farmers

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Abstract

This study was conducted at the Pest Management Laboratory of Sokoine University of Agriculture (SUA), Morogoro, Tanzania, to assess the efficacy bio-pesticides in controlling Prostephanus truncatus (Larger Grain Borer) in maize storage. The experiment was laid out in a Completely Randomized Design (CRD) with seven treatments, including one synthetic control (Actellic Super Dust) and five botanical powders (Lantana camara, Azadirachta indica, Tagetes erecta, Eupatorium capillifolium, and Citrus limon), each replicated three times. A total of 150g maize grains were placed in each bottle with 20 adult P. truncatus introduced to simulate infestation. The study monitored insect mortality, seed damage, and weight loss over four weeks. The results indicated significant differences among treatments in terms of insect mortality, seed damage, and weight loss. Actellic Super Dust showed the highest insect mortality and lowest seed damage, while Lantana camara demonstrated effective pest control as a botanical option, outperforming other bio-pesticides. Data were analyzed using GENSTAT software, with significant differences identified by ANOVA and means separated by Duncan's Multiple Range Test at P < 0.05. This research underscores the potential of both synthetic and botanical insecticides for effective maize storage pest management, contributing to reduced grain losses and supporting sustainable pest control practices for smallholder farmers in Tanzania.