Population genetic structure and migration patterns of the maize pathogenic fungus, Cercospora zeina in East and Southern Africa

•All 964 isolates from gray leaf spot lesions on maize in Africa were Cercospora zeina.•Rejected hypothesis of single introduction C. zeina into Africa (SSR diversity high)•Zambia population distinct – more migration between Kenya, Uganda, Zimbabwe, S. Africa.•Evidence for rare human-mediated dispersal of C.zeina between South and East Africa.•Longer annual cropping season in East Africa does not confer higher C. zeina diversity.