Cassava mosaic geminiviruses associated with cassava mosaic disease in Rwanda

• Published in: International journal of pest management 2005-03, Vol.51 (1), p.17-23
• Main Authors: Sseruwagi, P, Okao-Okuja, G, Kalyebi, A, Muyango, S, Aggarwal, V, Legg, J.P
• Format: Article
• Language: English
• Subjects: African cassava mosaic virus; Biological and medical sciences; Cassava; cassava mosaic disease; cassava mosaic geminiviruses; cutting infection; disease incidence; disease severity; East African cassava mosaic virus; epidemiological studies; Fundamental and applied biological sciences. Psychology; geographical variation; infection; Manihot esculenta; Pathology. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection; plant viruses; Plant viruses and viroids
• ISSN: 0967-0874; 1366-5863
• DOI: 10.1080/09670870400016750

Cassava mosaic disease (CMD), and cassava mosaic geminiviruses (CMGs), were investigated in a country-wide survey conducted in six cassava-producing prefectures (administrative regions) of Rwanda in 2001. CMD occurred throughout the country at an average incidence of 30%. Incidence was highest in Kigali (44%) and lowest in Butare (11%). Cutting infection resulting from the use of CMD-affected planting material was the main type of infection. Disease symptoms were generally severe, with little difference between cultivars or locations. Most affected plants lacked the 'candle-stick' symptoms characteristic of severe CMD associated with infection by the 'Uganda Variant' of East African cassava mosaic virus (EACMV-UG2). PCR analysis detected two viruses in CMD-affected plants: African cassava mosaic virus (ACMV) and EACMV-UG2. ACMV predominated and occurred throughout the surveyed areas, whereas EACMV-UG2 was restricted to the prefectures of Byumba, which border south-western Uganda and Kibungo in south-eastern Rwanda. No dual infections were detected.