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 succesfully
incorporated into elite CIMMYT maize inbred line (CML216) and tested in insect bioassays
in Kenya. Participatory Rural Appraisals showed that stem borers are indeed a 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.