Colletotrichum species associated with loquat anthracnose in Kagawa and Tokushima prefectures, Japan

Anthracnose caused by Colletotrichum species is a serious disease of loquat (Eriobotrya japonica), but the species of Colletotrichum that are associated with the disease in Japan have not been adequately surveyed. In this study, 46 isolates were isolated from diseased leaves and fruits of loquat in Kagawa and Tokushima prefectures in 2017 and 2018. On the basis of morphological features and molecular approaches, seven Colletotrichum species were identified: C. fioriniae, C. nymphaeae, C. karsti, C. aenigma, C. fructicola, C. gloeosporioides s. s., and C. siamense. The most prevalent species was C. karsti (43.5% of total species), followed by C. fioriniae (21.7%) and C. gloeosporioides s. s. (13.0%). All identified species were confirmed to cause loquat anthracnose by fulfilling Koch’s postulates. The loquat isolates of C. fioriniae, C. fructicola, and C. siamense also caused symptoms on all tested plants of kiwifruit, satsuma mandarin, persimmon, and peach. This report is the first on C. karsti and C. aenigma associated with loquat anthracnose and the first record of C. fructicola in Japan.