Lasiodiplodia theobromae (Pat.) Griffon & Maubl., Bull. Soc. mycol. Fr. 25: 57 (1909), Index Fungorum number: IF188476
Saprobic on dead twig of T. grandis. Sexual morph: Undetermined. Asexual morph: Conidiomata (65–)100– 120(−159) μm high × 146–218μm diam. (x = 110 × 186μm n = 10), pycnidial, semi-immersed, unilocular, solitary, scattered, globose or subglobose, dark brown. Conidiomata wall 20–50μm wide, outer layers dark brown to black, thick walled, inner layers thin-walled, pale brown to hyaline, comprising 2–3 layers of dark brown cells of textura angularis. Paraphyses up to 50μm long, 3.2–4μm wide, hyaline, septate, cylindrical, occasionally branched, ends rounded. Conidiogenous cells holoblastic, hyaline, thin-walled, smooth, cylindrical. Conidiogenous cells 6–16 × 3–6μm (x = 10 × 4μm n = 15), holoblastic, hyaline, cylindrical. Conidia (19–)20–24(−27) μm× 12–13μm (x = 23 × 13μm n = 30), initially hyaline and aseptate when immature, becoming medianly 1-euseptate, dark brown, thick-walled, ellipsoid to obovoid, base truncate or rounded, with longitudinal striations from apex to base.
Culture characteristics: Conidia germinating on PDA within 4–5 h. Colonies growing on PDA reaching 45 mm diam. after 1 day at 25 °C in the dark, initially whitened in a few days, after 7 days becoming grey (6F1), fast growing, raised, fluffy, dense, filamentous, reaching the edge of the Petri-dish after 2 days.
Habitat: Known to inhabit fruits, leaves and stems of multiple plant genera in multiple families (Farr et al. 2016) and dead twig of T. grandis (current study).
Known distribution: Widely distributed in tropical and subtropical regions (Farr et al. 2016).
Material examined: THAILAND, Phayao Province, Muang District, on dead twig of T. grandis, 12 March 2012, M. Doilom, MFLU 15–0730,living culture MFLUCC 12–0293, MKT 038, MUCL 55408, GenBank Accession No: ITS: KM396896, TEF1: KM409634, TUB: KM510354.
Notes: The morphology of this collection is similar to L. theobromae. It possesses septate paraphyses, the conidia are slightly smaller and narrower (23 × 13 versus 26.2 × 14.2 μm), than those reported by Alves et al.(2008) for the neotype. This may be due to the difference in substrate. However, phylogenetic analyses of L. theobromae (MFLUCC 12–0293) groups it with L. theobromae (ex-neotype) in Doilom et al. (2015) thus the collection is named as L. theobromae. This is the first report of L. theobromae from T. grandis in Thailand therefore, details are provided of this species to facilitate identification on this host.
FIG. Lasiodiplodia theobromae (MFLU 15–0730). a Appearance of conidia on host surface. b Section through conidioma. c Conidioma wall.d Conidiogenous cells with paraphyses. e Conidia attached to conidiogenous cells. f Immature conidia. g Paraphyses. h–k Mature conidia in two different focal planes showing longitudinal striations and without longitudinal striations. l Germinated mature conidium. Note g Stained in lactophenol cotton blue. Scale bars: a = 300 μm, b = 100 μm, c–f, k = 20 μm, g–k = 10 μm