Soil insect crop pests and their integrated management in East Africa: A review

Abstract

Soil-dwelling pests are generally poorly documented in East Africa due to their cryptic nature, which complicates monitoring, so the aim of this review is to compile and elucidate the current soil insect pest and management situation in this region. Fifty-five (55) soil insect pests are reported from across East Africa, and twenty (36%) and seventeen (30%) species of Scarabaeidae and Termitidae, respectively, and three families (Agromyzidae, Apionidae and Curculionidae) were found to be the most notorious soil insect pests in the region by far. Multiple species within the aforementioned families have been reported as the leading soil insect pests threatening the production of major crops in East Africa and include the banana weevil, Cosmopolites sordidus Germar; the sweet potato weevil, Cylas formicarius Fabricius; the bean maggots Ophiomyia spencerella Greathead, O. phaseoli Tryon and O. centrosematis de Meij; the cutworm, Agrotis segetum Schiff; and several species of termites and white grubs. The major control options rely heavily on preventive measures and to lesser extent, on direct control as a last resort. This review provides insight into the soil insect pest communities in East Africa as well as current control options and identifies knowledge gaps, such as an insufficient understanding of insect biology and ecology, highlights the lack of action threshold values as well as localized recommended rates of insecticides and underlines the need for education on pesticide use.