Four viruses are known to infect Musa cultivars in Africa. These are cucumber mosaic virus (CMV), banana bunchy top virus (BBTV), banana streak virus (BSV) and a previously unreported potexvirus. Two other viruses known to infect Musa, banana bract mosaic virus (BBMV) and abaca mosaic virus, have not been found in Africa. The viruses infecting Musa differ in their biology, mode of transmission and epidemiology, and these differences have important practical implications for the control of the diseases caused by these viruses. Effective control of virus diseases of Musa in Africa needs to be based on an understanding of the biology and epidemiology of the viruses involved, and on the availability of reliable methods of virus indexing. A special problem is posed by BSV due to the integration into the Musa genome of viral sequences which may subsequently cause disease expression.