Abstract
Colletotrichum species are significant pathogens of various economic plant hosts worldwide. In this study, 45 Colletotrichum isolates were obtained from symptomatic walnut leaves of walnut anthracnose in Shaanxi and Sichuan Provinces. In conjunction with morphological evidence and multi-gene phylogenetic analyses of internal transcribed spacer (ITS), actin (act), chitin synthase 1 (chs1), glyceraldehyde-3-phosphate dehydrogenase (gapdh) and beta-tubulin (tub2) sequences support the introduction of three new species, namely Colletotrichum cordae, C. guangyuanense and C. juglandium. Five species of Colletotrichum were identified to be C. fioriniae of the C. acutatum species complex, C. karsti of the C. boninense species complex, C. gloeosporioides, C. mengyinense and C. siamense of the C. gloeosporioides species complex. The three new species are described and illustrated in this paper and compared with taxa in the Colletotrichum gloeosporioides species complex. The current results improve the understanding of Colletotrichum species causing walnut anthracnose in China.