Abstract

Maize streak disease is a major threat to cereal crops amongst smallholder farmers in sub-Saharan Africa causing up to US$480 million losses annually. It is caused by Maize streak virus (MSV), a geminivirus that is indigenous to Africa. The virus is transmitted by at least 11 Cicadulina species, with Cicadulina mbila being the main vector. In addition to cereals, the virus also infects wild grasses. There are 11 known MSV strains, designated with the letters A to K, according to alphabetical order. MSV-A is the most severe and economically important strain that attacks maize. The other strains attack cereal crops other than maize. The control of MSV is most effective when cultural and chemical methods are integrated with plant breeding for resistance. While host plant resistance is the best method of MSV management, it is not usually easy to conventionally produce resistant cultivars. Genetic engineering has been successfully employed in producing MSV-resistant maize. However, opponents of genetic engineering have prevented the adoption of the technology by most African countries. This means that smallholder farmers have to continue growing susceptible cultivars or buy the slightly more expensive conventionally-bred cultivars.

Key words: Cicadulina, host range, integrated disease management, pathogen strains, symptoms.