Confirmation of Bacterial Leaf Streak Caused by Xanthomonas oryzae pv. oryzicola on Rice in Madagascar

Bacterial leaf streak (BLS) caused by Xanthomonas oryzae pv. oryzicola is an important disease of rice. BLS is prevalent in Asia and West Africa, where it was first reported in Nigeria and Senegal in the early 1980s (4). Recently, molecular analysis of strains from Mali (2) and Burkina Faso (5) further confirmed the presence of BLS in West Africa. In Madagascar, BLS symptoms were first reported in the 1980s by Buddenhagen but the causal agent was not unequivocally determined (1). To confirm Buddenhagen's observations using modern molecular typing tools, we surveyed several rice fields in the Antananarivo and Antsirabe districts in March 2013. BLS symptoms were observed on cultivated Oryza sativa grown under both upland and lowland conditions, with a proportion of diseased individuals varying from 30% up to 80%. Symptomatic leaves presenting water-soaked lesions that developed into translucent, yellow streaks with visible exudates at the surface were sampled. One to four centimeter long pieces of diseased ...