Juglanconis oblonga (Berk.) Voglmayr & Jaklitsch, Persoonia 38: 147 (2017)

Fan, Xinlei, Du, Zhuo, Bezerra, Jadson D. P. & Tian, Chengming, 2018, Taxonomic circumscription of melanconis-like fungi causing canker disease in China, MycoKeys 42, pp. 89-124 : 97-99

Juglanconis oblonga (Berk.) Voglmayr & Jaklitsch, Persoonia 38: 147 (2017) Fig. 4

≡ Melanconium oblongum Berk., Grevillea 2 (no. 22): 153. 1874.

= Diaporthe juglandis Ellis & Everh., Proc. Acad. Nat. Sci. Philadelphia 45: 448. 1893.

≡ Melanconis juglandis (Ellis & Everh.) A.H. Graves, Phytopathology 13: 311. 1923.

Descriptions.

Pseudostromata immersed in host bark, distinctly erumpent from surface of host branches, 1.5-3 mm diam. Ectostromatic disc indistinct, usually circular, greyish to brownish. Perithecia often appearing as rounded bumps beneath the bark surface surrounding the ectostromatic disc, prolonged black neck from the top, (450 –)525–700(– 780) µm diam. (av. = 580 μm, n = 30). Asci hyaline, clavate to fusoid, (120 –)122– 135 × (12.5 –)13– 16.5 (-17) μm (av. = 126.5 × 15 μm, n = 20). Ascospores hyaline, ellipsoid, broadly ellipsoid or broadly fusoid, symmetric to slightly asymmetric, straight, rarely slightly curved, constricted at the septum, (17 –)17.5–22(– 23.5) × (7.5 –)8–10.5(– 11) μm (av. = 19.5 × 9.5 μm, n = 50). Conidiomata acervular, immersed in host bark, erumpent from surface of host branches, scattered or occasionally confluent, 1-2 mm, covered by black discharged conidial masses at maturity, usually conspicuous. Ectostromatic disc buff to honey, surrounded by bark or not. Central column beneath the disc more or less conical, isabelline to olivaceous grey. Conidiophores cylindrical to lageniform, simple, rarely branched at the base, smooth, subhyaline to pale brown. Conidiogenous cells annellidic with distinct annellations, integrated. Conidia unicellular, initially hyaline, becoming brown to blackish when mature, broadly ellipsoid to broadly pip-shaped, truncate with distinct scar at the base, densely multiguttulate, thick-walled, (14 –)19–23.5(– 28) × (6.5 –)9–13(– 15) μm (av. = 22 × 12.5 μm, n = 50), with 0.8-1 µm wide gelatinous sheath.

Culture characteristics.

On PDA, cultures are initially white, becoming pale olivaceous grey after 10 d. The colonies are felty with an irregular edge; texture uniform; sterile.

Materials examined.

(all on twigs and branches of Juglans regia ). CHINA, Heilongjiang Province, Harbin City, Linan, Heilongjiang Botanical Garden, 45°42'21.10"N, 126°38'42.87"E, 2 August 2016, Q. Yang & Z. Du (BJFC-S1374; living culture, CFCC 51725; ibid.CFCC 51726).

Notes.

Juglanconis oblonga is based on Melanconium oblongum (= Melanconis juglandis ) ( Voglmayr et al. 2017). This species can be distinguished from J. juglandina by on average longer length of conidia (22 × 12.5 vs.> 20 × 13 µm). However, there is a substantial size overlap between both species and sequence data are sometimes necessary for reliable species identification. It was also recorded to cause canker and dieback disease of Juglans regia in China (China Microbiology and Virology Databases, http://www.micro.csdb.cn/).