Ascochyta herbicola (Wehm.) Qian Chen & L. Cai, Stud. Mycol. 82: 187 (2015) = Ascochyta rosae Tibpromma, Camporesi & K.D. Hyde, in Tibpromma et al., Fungal Diversity 83: 74 (2017)
Saprobic on the host plant in terrestrial habit. Sexual morph: see Tibpromma et al. (2017). Asexual morph: Conidiomata 190–240 μm diam., 110–230 μm high, brown, pycnidial, scattered, rarely gregarious, semi-immersed to superficial, globose to subglobose, unilocular, thick-walled, glabrous. Ostiole absent, dehiscing by an irregular rupture in the apical wall. Conidiomatal wall 20–50 μm wide, composed of relatively thick-walled, dark brown to brown cells of textura angularis in the basal part from exterior to conidial hymenium, becoming thinner in the upper part. Conidiophores mostly reduced to conidiogenous cells, occasionally present, short, cylindrical, septate and branched at base, formed from inner layers of peridium. Conidiogenous cells 6–13 × 2–4 μm, hyaline, enteroblastic, annellidic, lageniform, attenuated towards apex, discrete or integrated, indeterminate, smooth-walled. Conidia 4–7 × 1.5–2.6 μm ( ̄x = 5 × 2 μm; n = 50), hyaline, cylindrical to subcylindrical, rounded at both ends, straight or slightly curved, unicellular, thick- and smooth-walled.
Material examined: Russia, 20th anniversary of Red Army microdistrict, on dead stems of Potentilla sp. (Rosaceae), 21 May 2015, T.S. Bulgakov, T422 (MFLU 15-2126).
Notes: A new specimen (MFLU 15-2126) collected on Potentilla sp. in Russia nested between A. rosae (MFLUCC 15-0063) and A. herbicola (CBS 629.97). The sequence (LSU, ITS and rpb2) of the new collection are compared with A. rosae and A. herbicola, and the results showed only three loci (including two gaps) difference between the new collection and A. rosae in rpb2 except at the beginning and end, and also three loci difference between new collection and A. herbicola. In addition, our collection has similar conidia with A. herbicola (5–7(–8.5) × 2–3 μm, av. 6.2 × 2.3 μm (Degruyter et al. 1993). Thus, we treat these three collection as conspecific, and synonymize A. rosae under A. herbicola.
Ascochyta herbicola (MFLU 15-2126) a Herbarium package and specimen. b–c Appearance of black conidiomata on the host. d Vertical section of conidioma. e Section of peridium. f–i Conidiogenous cells and developing conidia. j Conidia. Scale bars d = 100 μm, e = 20 μm, f–j = 5 μm
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–80.