How different hermetic bag brands and maize varieties affect grain damage and loss during smallholder farmer storage

Abstract

Smallholder farmers in sub-Saharan Africa store harvested maize to provide food stocks between harvest seasons, which may be up to 12 months apart. Stored maize is highly susceptible to insect pest damage, hence the need for stored grain protection technologies such as hermetic bags. The current study evaluated the efficacy of five brands of hermetic bags in storing three maize varieties under two contrasting agro-ecologies in Guruve and Mbire districts of Zimbabwe, for two storage seasons. The hermetic bag treatments evaluated included: GrainPro Super Grain bag (SGB) IVR™, PICS bag, AgroZ® Ordinary bag, AgroZ® Plus bag and ZeroFly® hermetic bag, which were compared to grain stored in a polypropylene bag either untreated (negative control) or following admixture with a synthetic pesticide treatment, Actellic Gold Dust® (positive control). The maize varieties included a white hybrid, a pro-vitamin A biofortified orange and a local variety. All the hermetic bag treatments out-performed the synthetic pesticide in limiting grain damage and weight loss during storage. No significant difference in grain damage or weight loss was observed among the hermetic bags. However, rodents punctured some hermetic bags; therefore rodent control is recommended. A positive correlation with grain damage and weight loss for all three maize varieties was found for Sitophilus zeamais, Sitotroga cerealella, Tribolium castaneum and Cryptolestes spp adult numbers. Significantly higher insect damage and weight loss (P < 0.001) occurred in the white hybrid maize than in the other two varieties. The results confirmed that regardless of brand, all the hermetic bags tested can be recommended for smallholder farmer use to limit postharvest storage losses, avoid pesticide use, and support food and nutrition security.