Asteromella ovata
Asteromella ovata Thüm., Mycoth. Univ., cent.17: no. 1689 (1880) Fig. 1
Index Fungorum number: IF 197904; Facesoffungi number: FoF 06214
Epifoliar or epiphytes on the upper surface of living leaves leaves of Menispermum canadense L. (Menispermaceae). Colonies forming blackened 0.2–0.4 mm circular areas. Sexual morph: Undetermined. Asexual morph: Pycnidia 250–430 µm high × 196–210 µm diam., (x̅ = 343 × 203 µm, n = 10), hypophyllous, dark brown to black, globose to subglobose, superficial with irregular margins, sometimes sparsely scattered or not entirely distributed on surface of leaves. Peridium 13–18 µm, thick walled comprised of cells of textura globulosa. Conidiophores reduced to conidiogenous cells. Conidiogenous cells enteroblastic, phialidic, integrated or less often discrete, determinate, hyaline (Sutton 1980, van der Aa & Vanev 2002). Conidia 6.7–8 µm × 3–5 µm (x̅ = 8 × 5 µm, n = 10) cylindrical to ovoid, hyaline, 1-septate, ellipsoid to cylindrical apparently with 2-guttules, eguttulate.
Material examined – PARMA, Parma Botanical Garden, on leaves of Menispermum canadense L. (Menispermaceae), November 1878, Passerini (S-F40912, holotype).
Economic significance – The anamorphic genus Asteromella is a pathogenic genus causing dark lesions, stains, leaf spots and discoloration of host plant leaves in Poland (Ruszkiewicz-Michalska 2016). Asteromella is also associated with leaf blotch symptom of lime trees (Butin & Kehr 1995). The genus was also reported on withering leaves of Prunus armeniaca 'Aprikose von Nancy' (Bedlan 2014) as well as ring spots on Brussels sprout and cabbage in UK (Koike et al. 2007). The genus Asteromella is also a pistachio pathogen (Vitale et al. 2018).
Figure 1 – Asteromella ovata (S-F40912, holotype). a Details of herbarium material. b–d Herbarium specimen and habit on leaf. e Squash mounts of pycnidium. f Section of pycnidium. g Peridium. h Conidia. i Conidia stained in lactophenol cotton blue. Scale bars: c, d = 2 mm, e, f = 200 µm, g = 30 µm, h, i = 10 µm.
References
Bedlan G. 2014 – First report of Asteromella pruni-mahaleb comb. nov. (Syn. phyllosticta pruni-mahaleb pass.) on Prunus armeniaca. Journal fur Kulturpflanzen 66 (3), 90–94.
Butin H, Kehr R. 1995 – Leaf blotch of lime associated with Asteromella tiliae comb. nov. and the latter's connection to Didymosphaeria petrakiana. Mycological research 99 (10), 1191–1194.
Koike S, Gladders P, Paulus A. 2007 – Vegetable diseases: a color handbook. (Manson Publishing Limited: London).
Ruszkiewicz-Michalska M. 2016 –The genus Asteromella (Fungi, Ascomycota) in Poland. Monographiae Botanicae 106, 1–164.
Sutton BC. 1980 – The Coelomycetes. Fungi imperfecti with pycnidia, acervuli and stromata. Wallingford: CABI Publishing 1–696.
Van der Aa HA, Vanev S. 2002 – Revision of the species described in Phyllosticta. Utrecht: Centraalbureau voor Schimmelcultures. (Eds. Aptroot A, Summerbel RC, Verkley GJ.) CBS, Centralbureau voor Schimmelcultures, Utrecht an Institute of the Royal Netherlands Academy of Arts and Sciences. Pp 510.
Vitale S, Aiello D, Guarnaccia V, Luongo L et al. 2018 – Liberomyces pistaciae sp. nov., the causal agent of pistachio cankers and decline in Italy. MycoKeys 40, 29 –51.
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