Colletotrichum cymbidiicola Damm, P.F. Cannon, Crous, P.R. Johnst. & B.S. Weir

Classification – Glomerellaceae, Glomerellales, Hypocreomycetidae, Sordariomycetes, Ascomycota

Index Fungorum number – IF560740; Facesoffungi number – FoF 15258

Other useful webpages – outlineoffungi.org; fungalgenera.org; Sordariomycetes.org; coelomycetes.org

Description – Associated with leaf spot of Dendrobium nobile. Sexual morph: undetermined. Asexual morph: Conidiomata not observed. Conidiogenous cells forming from mycelium directly. Conidia 17–21 × 6–8 µm (av. 19 × 7 µm, n = 50), hyaline, smooth-walled, aseptate, cylindrical, both ends rounded, with a prominent scar, contents granular. Appressoria 9–14(–20) × 7–11 µm (av. 13 × 9 µm, n = 50), single, medium to dark brown, plum-shaped to irregular, outline variable, margin lobate.

Culture characteristics – Colonies on PDA reaching 85–90 mm diam. after 7 days at 25 ℃, flat, with entire margin, white, aerial mycelium dense, flocculent, reverse pink in the center, white towards margin.

Material examined – China, Guangdong Province, Zhaoqing City, on leaf spot of Dendrobium nobile Lindl. (Orchidaceae), July 2021, Yunxia Zhang and Jingwen Chen, (living culture ZHKUCC 23-0852, new host record).

Additional material – China, Guangdong Province, Meizhou City, on leaf spot of Cymbidium sinense (Jack. ex Andr.) Willd. (Orchidaceae), October 2021, Yunxia Zhang and Jingwen Chen (living culture ZHKUCC 23-0853, new host record).

GenBank accession numbers – gapdh: OR493863, OR493864, OR493865; act: OR493807, OR493808, OR493809; chs-1: OR493835, OR493836, OR493837; ITS: OR272084, OR272085, OR272086; tub2: OR453350, OR453351, OR453352.

Notes – See Zhang et al. (2023).

Colletotrichum cymbidiicola (ZHKUCC 23-0852, new host record). a, b Upper and reverse view on PDA (7 d). c Conidiogenous cells and conidia. d Conidia. e–h Appressoria. Scale bars: c–h = 10 µm.

Maximum likelihood  tree inferred from the combined ITS, gapdh, chs-1, act, and tub2 sequence data for Colletotrichum chamaedoreae, C. cymbidiicola, and C. karsti. The tree is rooted to C. truncatum (CBS 151.35). Maximum likelihood bootstrap support values equal to or greater than 70% and Bayesian posterior probabilities equal to or greater than 0.90 are given at the nodes and branches (ML/BYPP). Ex-type isolates are marked with “T”. The new isolates from South China region are indicated in red.