Banana Streak Badnavirus and Cucumber Mosaic Cucumovirus in Farmers' Fields in Zanzibar.

Symptoms resembling those of viral leaf streak disease, caused by banana streak badnavirus (BSV), were observed in May 1998 on two banana (Musa spp.) landraces grown from farmer-collected propagules in a farmer's field at Kiboje Uchukuni, Zanzibar. Those showing symptoms were "French plantain" cv. Mzuzu and "Cavendish" banana cv. Mtwike. Leaf symptoms were expressed as chlorotic streaks and blotches. Leaf samples were indexed by immunosorbent electron microscopy with BSV and cucumber mosaic cucumovirus (CMV) antibodies, using partially purified preparations (2). The two landraces tested positive for BSV, corroborating the occurrence of BSV in Zanzibar. In addition, cv. Mtwike was found to be coinfected with CMV. No other viruslike particles were seen by electron microscopy. Although BSV has been reported in Zanzibar (1), it was only from symptoms in the Musa field genebank at Kizimbani Research Station. BSV has been found in many Musa collections worldwide, particularly in the widely grown cv. Mysore. This report confirms the presence of BSV in farmers' fields and is also the first report of CMV infecting banana in Zanzibar. References: (1) A. J. Dabek and J. M. Waller. Trop. Pest Management 36:157, 1990. (2) M. Diekmann and C. A. J. Putter. Musa spp. FAO/IPGRI Technical Guidelines for the Safe Movement of Germplasm No. 15. FAO/IPGRI, Rome, Italy, 1996.