Cytospora leucostoma (Pers.) Sacc., Michelia 2(7): 264. 1881.

Jiang, Ning, Yang, Qin, Fan, Xin-Lei & Tian, Cheng-Ming, 2020, Identification of six Cytospora species on Chinese chestnut in China, MycoKeys 62, pp. 1-25 : 1

Cytospora leucostoma (Pers.) Sacc., Michelia 2(7): 264. 1881. Figure 5

Description.

Sexual morph: not observed. Asexual morph: Pycnidial stromata ostiolated, immersed in bark, scattered, erumpent through the surface of bark, with multiple locules. Conceptacle black. Ectostromatic disc black, circular to ovoid, (150-)250-300(-375) µm diam., with one ostiole per disc. Ostioles black, at the same level as the disc, (40-)50-85(-115) μm diam. Locule numerous, arranged circularly or elliptically with independent walls, (550-)700-1200(-1350) µm diam. Peridium comprising few layers of cells of textura angularis, with innermost layer brown, outer layer brown to dark brown. Conidiophores hyaline, unbranched, thin walled, filamentous. Conidiogenous cells enteroblastic polyphialidic, (7.5-)9.5-21(-22.5) × 1-1.5 μm (x̄ = 15.2 × 1.3 μm). Conidia hyaline, allantoid, smooth, aseptate, thin-walled, (3.5-)4.5-5.5(-7) × 1-1.5 μm (x̄ = 4.9 × 1.3 μm).

Specimens examined.

China, Hebei Province, Chengde City, Kuancheng County, chestnut plantation, 40°38'37"N, 118°27'5"E, on branches of Castanea mollissima , 13 October 2017, N. Jiang (BJFC-S1697, living culture CFCC 52461; BJFC-S1698, living culture CFCC 52462).

Notes.

Cytospora leucostoma is a common species causing canker disease on Rosaceae in China ( Teng 1963, Tai 1979, Wei 1979, Fan et al. 2020). In this study, fresh specimens were collected from diseased branches of the Chinese chestnut for the first time and identified as Cytospora leucostoma , based on strictly matched asexual morph (4-5.5 × 1-2 μm from Castanea mollissima in this study vs. 4.5-5.5 × 1-1.5 μm from multiple specimens in Fan et al. 2020) and phylogenic analysis (Fig. 2 ).

Figures

Figure 2. Maximum parsimony phylogram of Cytospora obtained from the combined matrix of ITS, LSU, ACT and RPB 2 genes. Bootstrap value ≥ 50 % for MP and ML analyses are presented at the first and second position. Scale bar = 200 nucleotide substitutions. The strains in the current study are in blue and ex-strains are marked with *.

Figure 5. Cytospora leucostoma on Castanea mollissima (BJFC-S 1697). A, B Habit of conidiomata on branches C transverse section of conidiomata D longitudinal section through conidiomata E conidiogenous cells attached with conidia F conidia. Scale bars: 500 μm (B-D), 10 μm (E, F).