Noctuidae is one of the largest lepidopteran families, encompassing about 20 000 species (Holloway 1998). Some 157 described species of Noctuidae are known to be cereal stem borers in the Afrotropical region (Moyal 2006) and the most economically important of these belong to the genera Busseola and Sesamia. Accurate identification of pest species is the first and most fundamental step to developing sound pest management strategies (Szalanski et al. 2003). However, many of these closely related stem borers are difficult to distinguish from each other morphologically, and no key is available to cover all noctuid stem borers (Holloway 1998).