Dendrostoma castaneicola C.M. Tian & N. Jiang

Jiang, Ning, Fan, Xin-Lei, Crous, Pedro W. & Tian, Cheng-Ming, 2019, Species of Dendrostoma (Erythrogloeaceae, Diaporthales) associated with chestnut and oak canker diseases in China, MycoKeys 48, pp. 67-96 : 75-77

Dendrostoma castaneicola C.M. Tian & N. Jiang sp. nov. Figure 5

Diagnosis.

Dendrostoma castaneicola differs from the two phylogenetically closely related species, D. castaneae and D. shaanxiense , by its white central column.

Holotype.

CHINA. Hebei Province: Chengde City, chestnut plantation, 40°24'32"N, 117°28'55"E, 262 m a.s.l., on branches of Castanea mollissima , 28 Apr. 2018, N. Jiang & C.M. Tian (holotype: BJFC-S1551; ex-type culture: CFCC 52743).

Etymology.

Castaneicola, referring to the host genus, Castanea .

Description.

Sexual morph not observed. Asexual morph: Conidiomata pycnidial, conical to pulvinate, occurring separately, reddish-orange, semi-immersed in bark, 300-550 μm high, 900-1600 μm diam.; wall of several layers of faint yellow textura angularis; central column beneath the disc more or less conical, white. Conidiophores reduced to conidiogenous cells. Conidiogenous cells lining the inner walls of the cavity, hyaline, smooth, subcylindrical to ampulliform, 5-14 × 2-3.5 μm. Conidia hyaline, aseptate, smooth, multiguttulate, thin-walled, ellipsoid to fusoid, straight, (9.3 –)10.5–12.8(– 13.8) × (3.1 –)3.2–3.8(– 4.1) μm, l/w = (2.3 –)3–4(– 4.4) (n = 50).

Culture characters.

On PDA, cultures are initially white, becoming black after 2 weeks. The colonies are flat with irregular edge; texture uniform, producing a circle with faint orange conidiomata distributed along the edge of the circle within 1 month at 25 °C in the dark.

Additional specimen examined.

CHINA. Hebei Province: Chengde City, Xinglong County, chestnut plantation, 40°21'44"N, 117°51'29"E, 256 m a.s.l., on branches of Castanea mollissima , 27 Apr. 2018, N. Jiang & C.M. Tian, living culture CFCC 52744 (BJFC-S1552).

Notes.

Dendrostoma castaneicola , D. castaneae and D. shaanxiense comprise three closely related pathogen species causing chestnut canker diseases in China, all three species occurring on Castanea mollissima . They differ with regard to conidiomatal characteristics, including conidial dimensions (Table 2) and the central column colour (pale yellow central column in D. castaneae vs. white in D. castaneicola vs. bright yellow in D. shaanxiense ). Additionally, Dendrostoma shaanxiense was only discovered in the Shaanxi Province, whereas D. castaneae and D. castaneicola were both distributed in Hebei Province.