Controlling the larger grain borer, Prostephanus truncatus in maize using host plant resistance and biological control techniques

Abstract

In East and West Africa, the accidental introduction of Prostephanus truncatus Horn (Coleopteras:Bostrichidae) in the early 1980s resulted in destructive outbreaks in small farm maize stores. Initial attempts to control the pest in Africa through the use of insecticides have had limited success. The use of host plant resistance and biological control as management strategies in the context of integrated pest management (IPM) are being evaluated in West Africa. Here we report on field and laboratory experiments to evaluate maize varietal effects on storage pest dynamics and grain damage and on some research studies investigating the underlying processes. Bionomics and predation behaviour of Teretriosoma nigrescens Lewis (Coleoptera:Histeridae), a biological control agent, currently being released in West Africa against P. truncatus are being evaluated as are the effects of competition between P. truncatus and Sitophilus zeamais Motschulsky (Coleoptera:Curculionidae). The effects of abiotic factors (temperature and relative humidity) are also investigated under a range of natural temperature/humidity regimes in different agro-ecological zones. A systems model, presently being developed, provides a unifying framework for considering the influence of these diverse biotic and abiotic factors. The potential use of this information in developing an IPM strategy is discussed