Two new Trichoderma species (Hypocreales, Hypocreaceae) isolated from decaying tubers of Gastrodia elate Author Ye, Chuwen Laboratory for Conservation and Utilization of Bio-resources, Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan, 650091, China Author Jing, Tingting Laboratory for Conservation and Utilization of Bio-resources, Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan, 650091, China Author Sha, Yuru Laboratory for Conservation and Utilization of Bio-resources, Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan, 650091, China Author Mo, Minghe Laboratory for Conservation and Utilization of Bio-resources, Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan, 650091, China minghemo@163.com Author Yu, Zefen Laboratory for Conservation and Utilization of Bio-resources, Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, Yunnan, 650091, China zfyu2021@163.com text MycoKeys 2023 2023-09-08 99 187 207 http://dx.doi.org/10.3897/mycokeys.99.109404 journal article http://dx.doi.org/10.3897/mycokeys.99.109404 1314-4049-99-187 641F017AA3D75F85AF877DA86E3F5928 Trichoderma albidum Z.F. Yu & T.T. Jing sp. nov. Fig. 2 Etymology. Referring to the rare white, whitish colonies on cultures media. Description. Sexual morph : Unknown. Asexual morph : Conidiophores straight or slightly curved, branches mostly asymmetrically arranged, also paired, sometimes at irregular intervals along the main axis, closely-spaced, often orientated toward the apex, rarely forming secondary branches. Phialides lageniform to somewhat subulate, straight or slightly curved, often with a narrow neck, often in whorls of 2-5, (6.0-) 8.3-13.5 (-15.7) x (2.9-) 3.2-4.6 (-4.8) µm , l/w ratio (1.5-) 2.0-4.0 (-4.5), (1.5-) 1.9-3.2 (-3.8) µm wide at the base, widest around the middle. Conidia ovoid to subglobose, sometimes oblong, hyaline, smooth, (3.5-) 3.7-5.3 (-6.3) x (3.2-) 3.3-4.2 (-4.8) µm (mean = 4.4 x 3.8 μm , n=50), l/w ratio 1.0-1.3 (-1.8). Culture characteristics. Optimum temperature for growth 25 °C. No growth at 35 °C in CMA, PDA and SNA. Colony radius on CMA after 3 days: 9-11 mm at 25 °C, 5-6 mm after 6 days at 30 °C, covering the plate after 11 days at 25 °C. Colony white to whitish, radial, not zonate, aerial hyphae sparse, arachnoid. Conidiation start after 4 days. Chlamydospores rare. No distinct odor noted, no diffusing pigment observed. Colony radius on PDA after 3 days: 22 mm at 25 °C, 11 mm at 30 °C, covering the plate after 7 days at 25 °C. Colony dense, pale white, finely zonate, circular, aerial hyphae abundant, fluffy. Conidiation start after 8 days, formed numerously on aerial hyphae. No distinct odor noted, no diffusing pigment observed. Colony radius on SNA after 72 h: 14 mm at 25 °C, 4 mm at 30 °C, covering the plate after 8 days at 25 °C. Colony hyaline, indistinctly zonate, aerial hyphae scarcely degenerating. Conidiation start after 7 days. Chlamydospores rare. No distinct odor noted, no diffusing pigment observed. Materials examined. China . Yunnan province , Zhaotong city, Yiliang county , Xiaocaoba Town , on diseased Gastrodia elata , 25 Oct. 2021 , T.T. Jing ( holotype YMF 1.7530). Ibid. (culture: YMF 1.7531) . Notes. Phylogenetically, T. albidum is associated with T. aggressivum . In comparison, T. aggressivum grows faster on PDA (50.5-56.0 mm after 3 days at 25 °C) and SNA (58.5-62.2 mm after 3 days at 25 °C), and produces shorter and narrower phialides ((4.0-) 5.7-7.8 (-21.0) x (1.3-) 2.7-3.5 (-4.3) µm ) and much smaller green conidia (3.2-3.3 x 2.8-2.9 μm ) ( Samuels et al. 2002 ). Figure 2. Morphology of Trichoderma albidum (YMF 1.7530) A-C cultures on PDA, 7d; SNA, 8d; CMA, 11d D-H conidiophores and phialides I conidia. Scale bars: 10 μm ( D-I ).