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Research topic: Evaluation of the establishment and efficacy of stem borer biological control agents released in Kenya
Objectives: Agriculture dominates the economy of most African countries and accounts for about 40-60% of their respective gross domestic product. In Sub-Sahara African countries, farmers grow mainly maize (Zea mays L.) and sorghum (Sorghum bicolor Moench.) for domestic consumption and as a cash crop. However, production of these crops is constrained by several factors varying from field pest infestations, poor soil fertility and unreliable climate. Important among these are field insect pests with lepidopteran stem borers accounting for yield losses ranging from 10 to 73%. In Eastern and Southern Africa, the four important stem borer pests of maize and sorghum include Chilo partellus, Chilo orichalcociliellus, Busseola fusca and Sesamia calamistis. Due to losses associated with stem borer infestations, different management strategies have been initiated. Among the control strategies, biological control provides environmentally sustainable, technically feasible and cost effective solution to most insect pest problems. Biological control agents released against stem borers in Kenya include Cotesia flavipes, Xanthopimpla stemmator, Cotesia sesamiae and Telenomus isis. However, one criticism of biological control is its lack of predictability in terms of agent establishment and success. In the Kenyan context, there is limited information on the establishment of these agents as only a few post release studies have been undertaken. Due to this information gap, it is difficult to discuss successes of the released biological control agents. This study thus seeks to determine the establishment and spread of the above biological control agents and assess their impact on target stem borer pests.