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Wanyama, J.

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Wanyama
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Wanyama, J.

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    Farmers, consumers and gatekeepers and their attitudes towards biotechnology
    (Academic Journals, 2011) Kimenju, S.C.; De Groote, H.; Bett, C.; Wanyama, J.
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    Evaluation of stem borer resistance management strategies for Bt maize in Kenya based on alternative host refugia
    (Academic Journals, 2011) Mulaa, M.; Bergvinson, D.J.; Mugo, S.N.; Wanyama, J.; Tende, R.; De Groote, H.; Tadele Tefera
    Stem borers are the major insect pests of maize in Kenya. The use of Bacillus thuringiensis (Bt) technology is an effective way of controlling lepidopteran pests. However, the likelihood of development of resistance to the Bt toxins by the target stem borer species is a concern. Forages, sorghum and maize varieties were evaluated for stem borer preference and survivorship in the laboratory and field in four locations in Kenya to identify suitable species and varieties for refugia. The economics of using the different kinds of refugia was also investigated. Vegetation surveys were conducted in 15 districts of Kenya to quantify the area covered by natural refugia. The field and laboratory trials indicated highest egg production, survivorship and more exit holes in all sorghum and maize varieties and some forages. Sorghum, non-Bt Maize, and improved Napier grass varieties Kakamega 1 and Kakamega 2) should be promoted as refugia species in Kenya. Some species and cultivars were identified as cost-effective, flexible, easily adoptable and compatible with farmers? common production practices. Refugia cultivar with multiple uses is expected to give higher pay-offs than one with single use. However, for successful management of a refugia strategy, strict stewardship is required from appropriate government or community institutions.
    Publication
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    Assessing the potential economic impact of Bacillus thuringiensis (Bt) maize in Kenya
    (Academic Journals, 2011) De Groote, H.; Overholt, W.A.; Ouma, J.O.; Wanyama, J.
    The Insect Resistant Maize for Africa (IRMA) project is currently developing Bt maize for Kenya. So far, Bt genes with resistance to Chilo partellus, Chilo orichalcociliellus, Eldana sacharina, and Sesamia calamistis, four of the five major stemborers were successfully incorporated into elite CIMMYT maize inbred line (CML216) and tested in insect bioassays in Kenya. Participatory Rural Appraisals showed that stem borers are indeed major pest problems for farmers. Four seasons of on-farm crop loss assessment showed an average crop loss of 13.5%, or 0.4 million tons, valued at US$ 80 million. If the project manages to find a Bt gene that is effective to the fifth stemborer, Busseola fusca, adoption rates are likely to be high, and therefore the returns. Under standard assumptions, the economic surplus of the project is calculated at $ 208 million over 25 years (66% of which is consumer surplus) as compared to a cost of $5.7 million. Geographically, the project should focus on the high production moist-transitional zone. However, if such gene cannot be found, Bt maize technology would only be effective in the low potential areas, and adoption rates would be fairly low, although benefits would still exceed costs.
    Publication