First report of Didymella leaf blight on Cornus officinalis caused by Didymella glomerata in China.
In May 2011, a leaf blight was found on Cornus officinalis in the Taiping township of Xixia County, Nanyang City, China. The disease occurred mainly in the summer, especially following rainy days, with foliar disease incidence of 52-86% (n = 300). Initially, water-soaked lesions were seen at the leaf tip (occasionally leaf base) of affected plants. The lesions developed from the leaf tips toward the leaf base and turned brown as the tissues dried up. The diseased tissues were taupe with multiple tiny black granules (pycnidia) under high humidity conditions. The causal pathogen was isolated and identified as Didymella glomerata based on morphological, molecular and pathogenicity analyses. The obtained sequences were deposited with GenBank accession nos. KC535018 and KY794938, respectively. This is thought to be the first report of D. glomerata causing leaf blight on C. officinalis in China.