Bipolaris maydis causing leaf blight on Rottboellia cochinchinensis in Brazil: a major crop pathogen on a major weed.
During 2009-2010, diseased Rottboellia cochinchinensis plants were found in the Brazilian states of Minas Gerais, Rio de Janeiro and Sao Paulo. These were mostly in ruderal situations, but also in the fields of an experimental station. Diseased plants had foliage bearing chlorotic areas that became necrotic, coalesced and developed into severe leaf blight. The causal pathogen was identified as Cochliobolus heterostrophus based on morphological, genetic (ITS) and pathogenicity analyses. This is thought to be the first report of C. heterostrophus on R. cochinchinensis in Brazil.