First report of leaf spot caused by Bipolaris victoriae on switchgrass in Georgia.
In the summer of 2010, light-to-dark brown, irregularly shaped leaf spots with white necrotic centres and chlorosis were observed on the switchgrass (Panicum virgatum) genotypes of the Southern Switchgrass Diversity Panel (SSDP) maintained at the University of Georgia in Watkinsville, Georgia, USA. Disease symptoms increased in the field each year and were observed on 30% of the SSDP entries during the summer of 2016. Symptomatic leaf tissue was collected from the field in 2016 and analysed in the the laboratory. The causal pathogen was identified as Cochliobolus victoriae based on morphological, molecular and pathogenicity analyses. This is thought to be the first report of the identification of C. victoriae on switchgrass in Georgia, USA.