Farmers' insect pest management practices and pesticidal plant use in the protection of stored maize and beans in Southern Africa

Abstract

Storage losses due to pests threaten livelihoods of farmers across Africa. Synthetic pesticides provide effective control when used correctly but resource-poor farmers cannot afford them. A survey of farmer ethno-ecological knowledge of pests of stored maize and bean, and their pest management practices including pesticidal plant use, was conducted in eastern Zambia and northern Malawi. Almost all respondents reported serious pest damage, with bruchids (Callosobruchus maculatus) and grain weevils (Sitophilus spp.) being major pests in beans and maize, respectively. The larger grain borer (Prostephanus truncatus) was reported more widely in Malawi. In Zambia, 50% of farmers used synthetic pesticides during storage, while nearly all did so in Malawi. Despite differences in storage methods between Malawi and Zambia, farmers in both countries were familiar with pesticidal plants, where Tephrosia vogelii was the most frequently reported. Surprisingly few farmers actually used pesticidal plants, highlighting a promotion opportunity. Our results provide a foundation for optimizing the use of pesticidal plants and enhancing their value to resource-poor farmers, across Africa.