Colletotrichum nymphaeae and Colletotrichum theobromicola isolated from anthracnose symptoms cause grape ripe rot

Colletotrichum species are the causal agents of grape ripe rot (GRR). However, Colletotrichum isolates have been isolated from symptoms of leaf grape anthracnose (GA) caused by Elsin & ouml;e ampelina infection. Thus, the present study aimed to evaluate whether Colletotrichum isolates obtained from grapes with GA are pathogenic on grapevine leaf, cane, or berry causing GA, or if they can cause GRR symptoms on ripe grapes. Colletotrichum isolates were characterized by genetic and morphological analyses as well as pathogenicity tests. One isolate of E. ampelina from GA and one of Colletotrichum acutatum complex (GL1) collected from GRR symptoms were used as reference isolates. Colletotrichum isolates from GA lesions were identified by genetic and morphological differences as C. nymphaeae (17 isolates) and C. theobromicola (one isolate). C. theobromicola was found for the first time associated with grapes in Brazil. C. nymphaeae and C. theobromicola did not cause lesions on grapevine leaf or cane, but the isolate of E. ampelina confirmed symptoms of typical GA. The Colletotrichum isolates from leaves were pathogenic on grapevine berries leading to GRR symptoms. Epidemiological studies on the relevance of Colletotrichum latent infection on leaves as a source of primary inoculum of ripe rot and the interference of co-infections of E. ampelina x Colletotrichum spp. on GA symptoms should be further investigated.