Cytospora schulzeri Sacc. & P. Syd., Syll. fung. (Abellini) 14(2): 918. 1899.

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 schulzeri Sacc. & P. Syd., Syll. fung. (Abellini) 14(2): 918. 1899. Figure 7

Description.

Sexual morph: not observed. Asexual morph: Pycnidial stromata ostiolated, immersed in bark, scattered, erumpent through the surface of bark, flat, discoid, with multiple locules. Conceptacle absent. Ectostromatic disc brown, circular to ovoid, (250-)300-400(-475) µm diam., with 1-5 ostiole per disc. Ostioles black, at the same level as the disc, (40-)50-85(-115) μm diam. Locule numerous, arranged circularly with common walls, (600-)700-1500(-1750) µm diam. Peridium comprising a 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, (6.5-)8.5-18.5(-21) × 1-2 μm (x̄ = 13.1 × 1.6 μm). Conidia hyaline, allantoid, smooth, aseptate, thin-walled, (3.5-)4.5-6.5(-7) × 1-1.5 μm (x̄ = 5.2 × 1.3 μm).

Specimens examined.

China, Hebei Province, Chengde City, Kuancheng County, chestnut plantation, 40°38'37"N, 118°27'54"E, on branches of Castanea mollissima , 13 October 2017, N. Jiang (living culture CFCC 52468; BJFC-S1702, living culture CFCC 52469; BJFC-S1703, living culture CFCC 52470).

Notes.

Cytospora schulzeri is a common species causing apple canker disease in China ( Teng 1963, Tai 1979, Wei 1979, Zhuang 2005, Fan et al. 2020). In this study, fresh specimens were collected from diseased branches of chestnut trees and identified as Cytospora schulzeri , based on the strictly matched asexual morph (4.5-6.5 × 1-2 μm from Castanea mollissima in this study vs. 4-7 × 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 7. Cytospora schulzeri on Castanea mollissima (BJFC-S 1702). 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).