Prostephanus truncatus in Africa: A review of biological trends and perspectives on future pest management strategies.

Abstract

The pest status of the Larger grain borer, Prostephanus truncatus (Coleoptera: Bostrichidae), is higher in African countries than in Latin America, its region of origin. This pest reduces the storage period of maize grain and cassava chips in granaries of small scale farmers. This reduced storage period results from larval and adult feeding, with consequent shortening of the period these commodities are available for food and income generating sources. Depending on storage time, yield losses of up to 45 and 100% have been recorded for maize and cassava chips, respectively, in West Africa; while 62% yield losses have been reported in Mozambique. Since P. truncatus invaded Africa from approximately 1970, research mostly addressed its biology, ecology, dispersal and control methods. This review paper aims at evaluating P. truncatus pest status in Africa as a basis for designing pragmatic strategies for its control. Prostephanus truncatus pest status in Africa is high and the degree of infestation and damage vary between regions. The variation in pest status is due to climatic conditions, food sources, and degree of storage infra-structure development and efficacy of control methods. Prostephanus truncatus has established in 20 African countries. Its temporal and spatial dispersion is unpredictable and depends on ecological factors, maize and dry cassava trade routes, and availability of forest host plants. Development of sustainable integrated management strategies is a key to future successful management of this pest. Area-wide management strategies using the predator, Teretrius nigrescens, parasitoids, plant derived products and environmentally friendly insecticides is needed. Integrated management practices must be based on improved knowledge of P. truncatus population dynamics and its determining factors.

Key Words: Integrated pest management, maize, Mozambique