Aschersonia Mont., Annls Sci. Nat., Bot., sér. 3 10: 121 (1848)

        = Underwoodina Kuntze, Revis. gen. pl. (Leipzig) 3(3): 538 (1891)

Index Fungorum number: IF 7236; MycoBank number: MB 7236Facesoffungi number: FoF 07396; 175 morphological species (Species Fungorum 2020), 12 species with sequence data.

Saprobic or parasitic on scale insects and whitefies. Sexual morph: see Chaverri et al. (2008). Asexual morph: Conidiomata reddish brown, formed from the body of an insect, stromatic, pycnidial, rounded or irregular in shape, multilocular, with immersed, globose, subglobose or obpyriform locules arranged peripherally in the same plane or irregularly in the inner stroma, glabrous, with or without ostiole. Conidiomatal wall composed of thick-walled, brown to hyaline cells. Paraphyses arising from the inner wall layer of locules, hyaline, filiform, tapered towards apex. Conidiophores reduced to conidiogeneous cells. Conidiogenous cells hyaline, enteroblastic, phialidic, cylindrical to subcylindrical, determinate, smooth-walled. Conidia hyaline, fusiform, straight or slightly curved, thick- and smooth-walled, guttulate, often in brightly colored mass, extruded in copious slime.

Type speciesAschersonia tahitensis Mont.

Notes Aschersonia, Moelleriella and Samuelsia are entomopathogenic fungi (Chaverri et al. 2008). They are similar in having stromatic, pycnidial, multilocular conidiomata, hyaline, filiform paraphyses and enteroblastic, phialidic conidiogenous cells. Aschersonia and Moelleriella have fusiform conidia, while Samuelsia has allantoid conidia (Chaverri et al. 2008; Tibpromma et al. 2017). Aschersonia was separated from Moelleriella by its sexual morph. Ascospores of Moelleriella usually disarticulate at maturity inside the ascus, whereas the ascospores of Aschersonia do not disarticulate inside the ascus (Chaverri et al. 2008). Aschersonia was initially recognized as plant parasite (Montagne 1848; Parkin 1906). However, it was reported as entomopathogenic by Webber (1897), and confirmed by Petch (1925). Accounts of the taxonomic history and phylogeny of Aschersonia were provided by Obornik et al. (1999), Sung et al. (2007a, b) and Hyde et al. (2020). Synonym of Aschersonia was provided by Kuntze (1891) as Underwoodina. Hypocrella was considered the sexual morph of Aschersonia and the preferred name (Rossman et al. 2016a, b). However, Hyde et al. (2020) preferred Aschersonia over Hypocrella as Aschersonia was the earlier name.

Distribution – Argentina, Australia, Brazil, Britain, Canada, Columbia, China, Cuba, Dominican, Ecuador, Guyana, India, Indonesia, Japan, Mauritius, Malaysia, Mexico, Netherlands, New Zealand, Papua New Guinea, Philippines, Poland, Puerto Rico, Senegal, Sir Lank, Sudan, Thailand, USA, Venezuela, Vietnam (Montagne 1848; Hooker 1855; Berkeley and Curtis 1869; Patouillard 1891; Saccardo 1892; 1893, Patouillard and Hariot 1900; Hennings 1902, 1904; Koorders 1907; Spegazzini 1911; Saccardo 1913; Sydow and Sydow 1917, 1914; Petch 1921; Kobayashi 1973; Obornik et al. 1999; Mongkolsamrit et al. 2009; Qiu et al. 2011; Tibpromma et al. 2017).