Colletotrichum chinensis Y. Zhang ter & L. Zhang 2024, sp. nov.

Colletotrichum chinensis Y. Zhang ter & L. Zhang sp. nov. Fig. 6 Holotype. QCG- 1. Etymology. Named after China where the fungus was collected. Description. Associated with walnut fruit and leaf anthracnose. Sexual morph not observed. Asexual morph developed on MEA. Conidiomata acervular, conidiophores hyaline, smooth-walled, septate, branched. Setae medium to dark brown, smooth to finely verruculose close to the tip, the tip rounded, 1–3 aseptate, 39.2–118.7 μm long. Conidiogenous cells subcylindrical, straight to curved, 16.7–30.0 × 2.3–3.7 μm (mean ± SD = 22.2 ± 0.6 × 3.2 ± 0.1 μm, n = 30). Conidia hyaline, smooth-walled, subcylindrical, both ends round, 1–3 - guttulate, contents granular, 13.7–18.5 × 4.4–5.9 μm (mean ± SD = 16.4 ± 1.0 × 5.0 ± 0.3 μm, L / W radio = 3.3, n = 100). Culture characteristics. Colonies on MEA flat with entire margin, surface pale pink, covered with felty white aerial mycelium aerial; reverse rosy buff to honey-coloured, growth rate 75–76 mm diam. in 7 d. Colonies on PDA flat with entire margin, surface pale pink, covered with felty white or grey aerial mycelium, grey aerial mycelium in the centre; reverse buff, rosy buff to honey-coloured, growth rate 79–80 mm diam. in 7 d. Appressoria produced on slide culture from conidia, medium to dark brown, variable in shape, often smooth-walled, subglobose, ovate to broadly elliptical in outline, 7.3–12.0 × 4.7–6.7 μm (mean ± SD = 9.5 ± 0.2 × 5.8 ± 0.1 μm, L / W radio = 1.6, n = 40). Material examined. China, Shandong Province, Taian City, on fruit of Juglans regia L., 29 July 2022, Y. Zhang, L. Zhang and L. L. Zhao (holotype, QCG- 1, culture ex-type, QCG- 1.1 = CGMCC 3.25209; culture QCG- 1.3 = CGMCC 3.25210); Beijing City, on fruit of Juglans regia L., 15 July 2022, Y. Zhang, L. Zhang and L. L. Zhao (JF 715-6, culture, JF 715-6.1 = CGMCC 3.25211; culture, JF 715-6.3 = CGMCC 3.25212). Notes. Phylogenetic analysis of the concatenated set of nucleotides from five loci indicated that Colletotrichum chinensis nested in the clade of C. gloeosporioides species complex and was closely related to C. citrulli, C. dimorphum, C. gloeosporioides, C. juglandicola, C. nanhuaensis and C. peakense (Cannon et al. 2008; Guo et al. 2022; Yu et al. 2022; Zhang et al. 2023). Morphologically, the strikingly longer conidia or appressoria of C. chinensis could be readily distinguishable from C. citrulli, C. dimorphum, C. gloeosporioides, C. juglandicola, C. nanhuaensis or C. peakense. Colletotrichum citrulli, C. dimorphum and C. nanhuaensis were originally reported from Ageratina Adenophora (Spreng.) King & H. Rob. and Citrullus lanatus (Thunb.) Matsum & Nakai, respectively in China (Guo et al. 2022). Colletotrichum juglandicola and C. peakense had been reported from Juglans regia L. as new species in China (Zhang et al. 2023). Thus, Colletotrichum chinensis was identified as a new species in this study, which caused anthracnose of Juglans regia.