Juglanconidaceae Voglmayr & Jaklitsch, Persoonia 38: 142 (2017)
Index Fungorum number: IF819587; 5 species.
Saprobic on dead corticated twigs and branches of Juglandaceae attached to trees. Sexual morph: Pseudostromata comprising an inconspicuous ectostromatic disc which is erumpent from the bark. Central column beneath the disc, nearly conical. Perithecia surrounding the central column, with a nearly globose base, with long lateral ostioles that emerge at the margin or within an ectostromatic disc. Asci 8-spored, clavate to fusoid, with a J-, apical ring. Ascospores overlapping 1–2-seriate, hyaline, broadly fusiform, bi-celled, slightly curved, guttulate, with or without gelatinous appendages. Asexual morph: Coelomycetous. Conidiomata acervular, with ectostromatic disc and conical central column. Conidiophores aseptate or septate, smooth, hyaline to brownish, occasionally branched. Conidiogenous cells annellidic. Conidia initially hyaline, becoming brown with age, various in shape, pip-shaped, narrowly ellipsoid, elongate to suballantoid, unicellular, often truncate with a scar at the base, with gelatinous sheath and irregular verrucae on the inner surface of the conidial wall (adapted from Voglmayr et al. 2017).
Type genus – Juglanconis Voglmayr & Jaklitsch
Notes – Juglanconidaceae was erected by Voglmayr et al. (2017) to accommodate four Melanconium species on hosts of Juglandinae, viz. three species (Juglanconis appendiculata, J. juglandina, J. oblonga) on various Juglans species, and one species (J. pterocaryae) from Pterocarya spp. (Voglmayr et al. 2019b). Du et al. (2017) introduced Melanosporellaceae to accommodate Melanosporella typified by M. juglandium. It was shown that the strains Juglanconis juglandina (MC1, ME16, ME22, ME23, MC3) from Austria and Spain and strains Melansporella juglandium (CFCC 51727, CFCC 51728, CFCC 51729) from China clustered together in the multigene phylogenetic analyses and share close morphological features (Du et al. 2017, Fan et al. 2018). Thus, Senanayake et al. (2018) treated Melanosporellaceae as a synonym of Juglanconidaceae. Juglanconidaceae seems specific to Juglandaceae tree species and cause black pustular dieback (Senanayake et al. 2018).
Ecological and economic significance of Juglanconidaceae
All species of Juglanconis have been reported on Juglandaceae (walnut family), such as Juglans ailanthifolia, J. cinerea, J. nigra, J. regia and Pterocarya rhoifolia. Juglanconis species have a wide distribution across Austria, China, the Czech Republic, France, Germany, Greece, Japan, Russia, Spain and the USA (Fan et al. 2018). Juglanconis juglandina and J. oblonga were regarded as the main causal agent of canker and dieback disease of Juglans regia in China (Fan et al. 2018).