STATUS OF GREY LEAF SPOT DISEASE IN KENYAN MAIZE PRODUCTION ECOSYSTEMS

Grey leaf spot disease (GLS), Cercospora zeae-maydis, which has previously been attributed to diverse pathogen species in other countries, has become a serious biotic constraint to production of maize (Zea mays L.) in Kenya. It is necessary to determine the distribution and aetiology of the disease across all the maize production agro-ecologies in order to inform the development of appropriate management strategies against the disease. Samples were collected from maize growing areas in Kenya with GLS symptoms on maize crops and other plants. On the basis of cultural and morphological examinations, and restricted fragment length polymorphism and taxon-specific PCR analyses, Cercospora zeae-maydis group II and C. sorghi var. maydis were identified from typical GLS lesions on maize, with the former being predominant ( 96% of the cases) and distributed throughout the country. The latter exhibited minor incidence ( 4%) in western Kenya. Nucleotide sequence analyses further provided evidence that C. zeae-maydis group II and C. sorghi var. maydis were distinct fungi.