CBN-V Video Archives - S8-22
Practical Applications of Biotechnological Tools in Diagnosing, Monitoring and Controlling Cassava Mosaic Geminiviruses in East and Central Africa

Sseruwagi P., G. Okao-Okuja, R. Obonyo and J.P. Legg

International Institute of Tropical Agriculture (IITA), Eastern and Southern Africa Regional Centre, P.O. Box 7878, Kampala, Uganda
iitanam@infocom.co.ug ; JLEGG@INFOCOM.CO.UG

        Cassava mosaic disease (CMD) has been recorded in East and Central Africa for more than a century. It was not until the early 1980s, however, that the viral aetiology of the disease was described and only in 1994 that the first information on the Africa-wide distribution of cassava mosaic geminiviruses (CMGs), was presented. The viruses belong to the Family Geminiviridae:, Genus Begomovirus, and are the causal agents of CMD. Prior to 1994, CMD was only monitored using visual assessments of disease severity and incidence. In recent years, there is a spread within the region of an epidemic of unusually severe CMD caused by the Ugandan variant of East African Cassava Mosaic Virus (EACMV-Ug). This has encouraged research efforts to diagnose and characterise viruses associated with CMD using new biotechnological diagnostic tools such as the polymerase chain reaction (PCR). The diagnostic technique is very sensitive and can discriminate between related viruses. The tool has been used to establish the distribution of different CMGs in the region, to quantify current disease spread and it has helped to forecast future spread. The CMD pandemic continues to expand southwards and westwards. The molecular diagnostic tool will continue to play a key role in forecasting spread, identifying worst affected areas and targeting control strategies based on the deployment of host plant resistance.

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