The Diversity of Cassava Mosaic Begomoviruses in Africa

Cassava mosaic disease (CMD) is the most widespread and economically important disease of cassava (Manihot esculenta Crantz) in tropical Africa. A disease of cassava was first described in East Africa in the nineteenth century (Warburg, 1894) and cassava mosaic, as it came to be called, was subsequently reported as spreading throughout the cassava-growing areas of Central and West Africa (Calvert and Thresh, 2002). In more recent times, CMD has been reported as occurring at varying levels of incidence throughout the cassava belt of Africa and losses have been estimated at between 12% and 25% of total production (Thresh et al., 1997).