Anthracnose and similar symptoms on mango leaves are caused by several other pathogenic fungi, including Colletotrichum spp.

Abstract

Mango anthracnose occurs in several Colletotrichum species and is characterized by brown to dark brown symptoms on leaves. In this study, the C. gloeosporioides species complex (CGSC) (a reported pathogen) and several other fungi were isolated from leaves with typical anthracnose symptoms. Several typical strains forming different colonies were isolated from anthracnose, and its symptoms were investigated. Morphological observations and genetic analysis of four representative strains based on the internal transcribed spacer (ITS), elongation factor 1-alpha (EF1-α), and β-tubulin gene (TUB) regions revealed that they were from the C. gloeosporioides species complex, Botryosphaeria ramosa, Diaporthe sp., Neofusicoccum mangiferae, and Neopestalotiopsis sp.. Observation of disease symptoms revealed that the leaves inoculated with B. ramosa, Diaporthe sp., and N. mangiferae were significantly similar to typical anthracnose symptoms and could not be distinguished visually. Only Neopestalotiopsis sp. caused light brown symptoms with small black spots, which were clearly different. When the C. gloeosporioides species complex and four isolated fungi from mango leaves were inoculated simultaneously onto healthy mango leaves, only Neopestalotiopsis sp. caused white to pale brown symptoms, whereas the other three species showed symptoms similar to anthracnose. However, inoculation of the fruit showed that the initial disease symptoms of N. mangiferae were only similar to those of anthracnose, whereas the other three species showed distinctly different symptoms. Thus, anthracnose symptoms on mango leaves in Okinawa are not solely caused by Colletotrichum spp., but also by several other pathogenic fungi including B. ramosa, Diaporthe sp., and N. mangiferae.