Phyllosticta cussoniae Cejp, Bothalia 10: 341. 1971.
Index Fungorum: IF320339; Facesoffungi: FoFxxxxx; MycoBank: MB320339.
Pathogenic on leaf spots of Cussonia umbellifera. Leaf spots 0.5–1 cm diam., amphigenous, subcircular, pale to medium brown, frequently surrounded by a red-purple margin. Sexual morph: Unknown. Asexual morph: Conidiomata (on PNA) up to 200 μm diam., pycnidial, solitary, black, erumpent, globose, exuding colourless to opaque conidial masses. Peridium composed of several layers of textura angularis; inner wall of hyaline textura angularis. Ostiole 20 μm diam., central. Conidiophores 10–25 × 3–5 μm, subcylindrical to ampulliform, reduced to conidiogenous cells, or with 1–2 supporting cells, branched at base. Conidiogenous cells 5–10 × 3–4 μm, terminal, subcylindrical, hyaline, smooth, coated in a mucoid layer, proliferating several times percurrently near apex. Conidia (10–)12–15(–17) × (6–)7(–8) μm, solitary, hyaline, aseptate, thin and smooth walled, coarsely guttulate, or with a single large central guttule, ellipsoid to obovoid, tapering towards a narrow truncate base, 3–4 μm diam., enclosed in a thin, persistent mucoid sheath, 2–4 μm thick, and bearing a hyaline, apical mucoid appendage, (8–)10–12(–13) × 2(–3) μm, flexible, unbranched, tapering towards an acutely rounded tip. Spermatia 7–10 × 2–3 μm, occurring in same conidioma with conidia, hyaline, smooth, guttulate to granular, bacilliform.
Culture characteristics: Colonies erumpent, spreading, with sparse aerial mycelium and feathery margins, covering the dish in 1 month. On MEA surface olivaceous-grey, reverse iron-grey; on OA iron-grey; on PDA iron-grey on surface and reverse.
Representative isolates: South Africa, Mpumalanga, Schagen, Nelspruit, on Cussonia umbellifera, 25 Dec. 1933, L.C.C. Liebenberg, holotype PREM 32871; Eastern Cape, Graaff Reinet, Valley of Desolation, on leaf spot of Cussonia sp., 9 Jan. 2008, P.W. Crous, epitype CBS H-21393, CPC 14874, 14873 = CBS 136060; MBT176246 (cultures ex-epitype); Gauteng, Walter Sisulu National Botanical Garden, on leaves of Cussonia sp., 2 Mar. 2007, P.W. Crous, cultures CPC 13812–13813.
Host: Cussonia sp. (Wikee et al. 2013).
Known distribution: South Africa (Wikee et al. 2013).
GenBank Numbers: ITS - JF343579, LSU - KF206278, TEF - JF343600, ACT - JF343663, GPDH - JF343765.
Notes: Phyllosticta cussoniae occurs commonly on various Cussonia spp. throughout South Africa, where it causes a prominent leaf spot disease. All isolates collected from the various provinces where this host occurs, appear to have the same species (based on DNA sequence data) associated with the disease.
Wikee S, Lombard L, Nakashima C, Motohashi K, Chukeatirote E, Cheewangkoon R, McKenzie EHC, Hyde KD, Crous PW (2013) A phylogenetic re-evaluation of Phyllosticta (Botryosphaeriales). Studies in Mycology 76: 1–29.