Liberomyces pistaciae Voglmayr, S. Vitale, D. Aiello, Guarnaccia, Luongo & Belisario

Vitale, Salvatore, Aiello, Dalia, Guarnaccia, Vladimiro, Luongo, Laura, Galli, Massimo, Crous, Pedro W., Polizzi, Giancarlo, Belisario, Alessandra & Voglmayr, Hermann, 2018, Liberomycespistaciae sp. nov., the causal agent of pistachio cankers and decline in Italy, MycoKeys 40, pp. 29-51 : 32-34

Liberomyces pistaciae Voglmayr, S. Vitale, D. Aiello, Guarnaccia, Luongo & Belisario sp. nov. Fig. 6

Diagnosis.

Species with distinctly smaller conidia (3.2-5.0 × 1.0-2.0 μm) than in Liberomyces saliciphilus Pažoutová, M. Kolařík & Kubátová and L. macrosporus Pažoutová, M. Kolařík & Kubátová.

Type.

ITALY. Sicily: Bronte (Catania province), on cankered twig of Pistacia vera , June 2010, A. Belisario (holotype: WU 39967; ex-type culture CBS 128196 = ISPaVe1958).

Etymology.

Named after its host genus, Pistacia .

Description.

Conidiomata pycnidial, superficial or immersed, single to densely aggregated, subglobose or cupular, uni- or irregularly plurilocular, first hyaline to pale brown, turning dark brown to blackish, without ostiole, irregularly rupturing at the apex and exuding a pale whitish conidial drop at maturity, (100 –)170–260(– 330) µm diam. (n=40). Pycnidial wall thin, of pale brown cells, (2.0 –)3.5–6.3(– 10.0) μm diam. (n=162) forming a textura angularis, outside darker, thicker-walled and more rounded, inside lined by a layer of angular hyaline cells giving rise to conidiophores. Conidiophores short, densely fasciculate, up to three times branched, hyaline, smooth, arising from the inner wall of the entire conidioma, 10-28 µm long. Conidiogenous cells holoblastic with sympodial proliferation, lageniform to cylindrical, (5.5 –)6.5–8.5(– 10.0) × 1.7 –2.5(– 2.7) µm (n=52), in dense intercalary or terminal whorls of 2-9. Conidia straight to allantoid, hyaline, smooth, 1-celled, (3.2 –)3.8–4.5(– 5.0) × (1.0 –)1.2–1.5(– 2.0) μm, l/w = (2.0 –)2.7–3.5(– 4.7) µm (n=182).

Culture characteristics.

Colonies slow-growing (about 4 cm in diam. in 1 month on MEA, 4 cm in 2 weeks on CMD at 22 °C), initially white, turning pale to dark brown with age, with a whitish slightly lobed margin (Fig. 6a and b), surface mycelium sparse. Red to brown pigments diffusing in growth medium. Densely aggregated pycnidia formed after 7 d on the inoculum plug, successively also on the colony surface.

Notes.

Morphologically, Liberomyces pistaciae is similar to the other two species of the genus, L. macrosporus and L. saliciphilus , but the latter have distinctly longer conidia (5-7.5 µm in L. saliciphilus , 8-13 µm in L. macrosporus ).