Diaporthe amygdali Udayanga, Crous & K. D. Hyde

Diaporthe amygdali (Delacr.) Udayanga, Crous & K. D. Hyde, Fungal Diversity 56 (1): 166. 2012 Fig. 6 Description. Associated with leaf spot disease of Alnus nepalensis. Teleomorph: Undetermined. Anamorph: Conidiomata formed on PDA pycnidial, scattered, erumpent, subglobose, dark brown, 700–2250 μm diam. Conidiophores indistinct, usually reduced to conidiogenous cells. Conidiogenous cells cylindrical, attenuate towards the apex, hyaline, phialidic, 16.5–34 × 1.5–3 μm. Alpha conidia not observed. Beta conidia aseptate, hyaline, smooth, guttulate, filiform, tapering towards both ends, straight or slightly curved, (27.5 –) 30–35 (– 40.5) × 1.5–2 μm (x ̄ = 32.6 × 1.6 μm, n = 50), L / W = 15.8–23.1. Gamma conidia not observed. Culture characteristics. Colonies on PDA at 25 ° C are flocculent, forming concentric zones with undulate margins, initially white, turning pale brownish, and reaching a diameter of 90 mm after 10 d, developing dark brown conidiomata with white conidial masses after 25 d. Colonies on MEA at 25 ° C are flat, spreading, with a smooth entire margin, white, reaching a diameter of 80 mm after 20 d, sterile. Colonies on SNA at 25 ° C are flat, spreading with a feathery margin, white, reaching 80 mm in diameter after 20 d, sterile. Materials examined. China • Xizang Autonomous Region (Tibet), Linzhi City, Bayi District, Pailong Town, 30°4'22"N, 95°8'2"E, 2192 m, from leaf spots of Alnus nepalensis, 9 Jul. 2024, Ning Jiang, Jieting Li & Haoyin Zhang (cultures CFCC 70999 and Q 3 B). Notes. The species concept of Diaporthe amygdali has been revised in recent studies using phylogenetic analysis, GCPSR, and coalescence-based models (Hilário et al. 2021 b; Dissanayake et al. 2024). Currently, D. amygdali is considered synonymous with D. chongqingensis, D. fusicola, D. garethjonesii, D. kadsurae, D. mediterranea, D. ovoicicola, D. sterilis, and D. ternstroemia (Hilário et al. 2021 b; Dissanayake et al. 2024). This fungus is widely distributed, inhabiting a range of plant hosts, including Acer spp., Camellia sinensis, Lithocarpus glabra, Prunus dulcis, Prunus persica, Prunus salicina, Pyrus pyrifolia, Ternstroemia gymnanthera, Vaccinium corymbosum, and Vitis vinifera (Hilário et al. 2021 b). In this study, two isolates from leaf spots of Alnus nepalensis clustered with strains of D. amygdali with high support values (Fig. 2). Therefore, these two isolates were identified as D. amygdali, which led us to describe Alnus nepalensis as a new host for this fungus.