Identification of Epicoccum latusicollum causing leaf spot disease on Bletilla striata in China

Abstract

Bletilla striata, a perennial herbaceous orchid, has been used in traditional Chinese medicine for centuries. Recently, a leaf spot disease on B. striata, resulting in plant mortality, was observed in Guangxi Province, China. In order to determine the pathogen causing the disease, we employed a conventional pathogen isolation method and conducted pathogenicity test. Based on morphological characteristics and phylogenetic analyses of the combined sequences of ITS, LSU, RPB2, and TUB2 genes, the pathogenic fungus was identified as Epicoccum latusicollum. Koch's postulates, which were fulfilled by the re-isolation of the pathogens from inoculated plants and their re-identification, confirmed that E. latusicollum is the causal agent of the disease. This study contributes to the knowledge of diseases on B. striata and provides valuable information for the identification and prevention of the leaf spot disease caused by E. latusicollum.