Morphological and molecular identification of Colletotrichum siamense associated with Cayratia japonica anthracnose in China

Cayratia japonica is widely used as a traditional medicine in China. Recently, it has been affected by anthracnose disease, which influences its growth and medicinal value. This disease has occurred extensively in Nanchang, Jiangxi, China, but the causal agent of anthracnose on this host is unknown. Colletotrichum-isolates were obtained from the diseased leaves. On PDA, the fungus produced white, mycelium on the surface and light gray at the bottom with dark-green pigmentation around the inoculation point. The fungal isolate was classified as Colletotrichum siamense based on morphological features and multi-genes phylogenetic analyses. Pathogenicity tests were conducted by inoculating with conidial suspensions on leaves, and Koch's postulates were confirmed. This is the first report that C. siamense causes anthracnose on C. japonica in China. •New Cayrati japonica disease was reported.•New host of Colletotrichum siamense was verified.