Virus Diseases of Economic Importance on Food Legumes in Africa and Their Control.

Virus diseases are among the major constraints in the production of food legumes in Africa, causing substantial crop losses. Common bean mosaic and black root, cowpea mosaic, chickpea stunt, faba bean necrotic yellows and stunt, groundnut rosette, and soybean mosaic are the six diseases considered economically significant in Africa. Past research enabled the description of the main characteristics of the causal viruses, including particle and genome properties, modes of transmission, host range, and virus-vector relationships. Such information in many cases assisted in developing effective diagnostics and disease management methods such as host resistance, chemical vector control, and cultural practices. Integrating two or more of these approaches is usually more effective. The major challenge, however, remains ensuring the adoption of such recommendations at a sufficiently large scale by many farmers to have an impact over wider geographical areas. Future work should focus on scaling up the adoption of available control technologies and generating new information, including epidemiological data, to support future management decisions. Furthermore, since the occurrence and significance of viruses on food legumes in many African countries are still not studied, large-scale surveys to identify viruses, establish their distribution and impact, and working out suitable control measures are required.