First report of Maize chlorotic mottle virus and maize lethal necrosis in Kenya.
In September 2011, a high incidence of a new maize (Zea mays) disease was reported at lower elevations (1,900m asl) in the Longisa division of Bomet County, Southern Rift Valley, Kenya. Diseased plants had symptoms characteristics of a virus diseases: a chlorotic mottle on leaves, developing from the base of young whorl leaves upward to the leaf tips; mild to severe leaf mottling; and necrosis developing from leaf margins to the mid-rib. Because of the high thrips populations and foliar symptoms, symptomatic plants were tested for the presence of Maize chlorotic mottle virus (MCMV). Of 17 symptomatic leaf samples from each Bomet and Naivasha, 9 from Bomet and all 17 from Naivasha were positive for MCMV. However the observed symptoms were more severe than commonly associated with MCMV, suggesting the presence of maize lethal necrosis (MLN). Therefore, samples were tested for the presence of Sugarcane mosaic virus (SCMV). Twenty-seven samples were positive for SCMV and 23 of 24 samples were infected with both viruses. Amplicon sequences had 96 to 98% identity, and were 88 to 96% identical with SCMV sequences in GenBank. This is thought to be the first report MCMV and of maize coinfection with MCMV and SCMV associated with MLN in Kenya and Africa.