Diplodia corticola
Diplodia corticola A.J.L. Phillips, A. Alves & J. Luque, Mycologia 96: 603. 2004.
Index Fungorum: IFxxxxx; Facesoffungi: FoFxxxxx; MycoBank: MBxxxxx.
Saprobic on dead branches of Quercus suber. Sexual morph: Ascostromata up to 1 mm diam., stromatic, solitary or aggregated, immersed, partially erumpent when mature, dark brown to black, more or less circular, uniloculate, locules 200−300 μm diam., thick-walled, wall composed of outer layers of thick-walled, dark brown textura angularis, inner layers of thin-walled, hyaline textura angularis. Ostiole circular, central, papillate, periphysate. Pseudoparaphyses 2−3 μm wide, hyaline, branched, septate. Asci 160−250 × 30−35 μm (including stipe), clavate, stipitate, bitunicate, containing eight, biseriate ascospores. Ascospores (28.5−)30−38(−40.5) × (13−)14−18.5(−19) μm, 95 % confidence limits = 33.6–35 × 15.3–16.2 μm (av. ± S.D. = 34.3 ± 2.4 × 15.8 ± 1.5 μm, n=90), L/W ratio = 2.2, broadly fusiform to rhomboid, widest in the middle, both ends obtuse, hyaline, moderately thick-walled (ca. 1 μm), smooth-walled, aseptate, rarely becoming light brown and 1–2-septate with age. Asexual morph: Conidiomata up to 1 mm diam., eustromatic, solitary or aggregated, immersed, partially erumpent when mature, dark brown to black, more or less circular, uniloculate, locules 200−300 μm diam., wall composed of three layers, an outer of dark brown, thick-walled textura angularis, a middle layer of dark brown thin-walled cells, and an inner layer of thin-walled hyaline cells. Ostiole central, circular, papillate. Conidiophores reduced to conidiogenous cells. Conidiogenous cells 12−19(−24) × 4−6 μm, holoblastic, discrete, cylindrical, hyaline, smooth, indeterminate, proliferating at the same level giving rise to periclinal thickenings, or proliferating percurrently to form one or two indistinct annellations. Conidia (23.5−)26−34.5(−46) × (9−)12−16(−18.5) μm, 95 % confidence limits = 29.6–30.3 × 13.4–13.8 μm (av. ± S.D. = 29.9 ± 2.5 × 13.6 ± 1.4 μm, n=250), L/W ratio = 2.2, hyaline, aseptate, eguttulate or sometimes with a large central guttule, contents granular, smooth, thick-walled, oblong to cylindrical, straight, both ends broadly rounded, rarely becoming brown and septate when aged.
Culture characteristics: Colonies reaching 36−44 mm diam. on PDA after 4 d in the dark at 25 °C. Cardinal temperatures for growth: min 5 °C, max < 35 °C, opt 20−25 °C.
Representative isolate: Portugal, Beira Littoral, Requeixo near Aveiro, on dead branches of Quercus suber, Feb. 2002, A. Alves, holotype LISE 94839, CBS 112549 (ex-type culture).
Hosts: Quercus species (Alves et al. 2004).
Known distribution: Iberian Peninsula, Italy, N. America (Alves et al. 2004), Tunisia (Linaldeddu et al. 2013), Algeria (Smahi et al. 2017).
GenBank Numbers: (Sequences associated with the type).
Notes: Diplodia corticola is responsible for dieback and cankers on Q. suber and Q. ilex and has contributed to the general decline of cork and other oaks throughout the Western Mediterranean region.
References:
Alves A, Correia A, Luque J, Phillips A (2004) Botryosphaeria corticola, sp. nov. on Quercus species, with notes and description of Botryosphaeria stevensii and its anamorph, Diplodia mutila. Mycologia 96: 598–613.
Linaldeddu BT, Franceschini A, Alves A, Phillips AJL (2013) Diplodia quercivora sp. nov.: a new species of Diplodia found on declining Quercus canariensis trees in Tunisia. Mycologia 105: 1266–1274.
Smahi H, Belhoucine-Guezouli L, Berraf-Tebbal A, Chouih S, Arkam M, Franceschini A, Linaldeddu BT, Phillips AJL (2017) Molecular characterization and pathogenicity of Diplodia corticola and other Botryosphaeriaceae species associated with canker and dieback of Quercus suber in Algeria. Mycosphere 8: 1261–1272.