Occurrence of Papaya Anthracnose Caused by Colletotrichum spp. in Korea

Anthracnose symptoms were found on fruit of papaya trees (Carica papaya) cultivated in greenhouses in Taean and Gokseong, Korea, during surveys of crop diseases in 2020 and 2021. The initial symptoms on the fruit appeared as small, water-soaked, slightly depressed, circular or oval brown spots. As the disease progressed, the symptoms turned sunken, dark brown to black, and enlarged. In the later stages, yellowish conidial masses formed on the lesions. The disease symptoms on the fruit occurred up to 5% in the investigated greenhouses. Seven single-conidium isolates were obtained from the diseased fruit and found to correspond to Colletotrichum sp. based on their morphological characteristics. Two out of the seven isolates were identified as Colletotrichum aenigma, and the others as Colletotrichum fructicola by analysis of phylogenetic characteristics. The isolates of C. aenigma and C. fructicola were tested for their pathogenicity on papaya fruit using artificial inoculation. Both the Colletotrichum spp. isolates induced anthracnose symptoms in papaya fruit, similar to those observed in the investigated greenhouses. This is the first report of C. aenigma and C. fructicola causing papaya anthracnose in Korea.