Coniothyrium yuccicola Chaiwan, Jayaward., Bulgakov & K.D. Hyde, sp . nov .

MycoBank number: MB; Index Fungorum number: IF; Facesoffungi number: FoF 08170;

Etymology: Based on the host genus Yucca.

Holotype: MFLU 17–2529.

Plant pathogenic on leaves and peduncle stems of Yucca filamentosa L. (Asparagaceae). Asexual morph: Conidiomata 250–450 μm (x¯ = 329 μmn = 10) diam., superficial on or immersed in the host. Conidiophores not present. Conidiogenous cells lining entire cavity, hyaline, cylindrical, 8±15 (av.11.9 lm) 3±8 lm (av.¯5.1 lm), longer than on host. Conidiogenesis holoblastic, proliferating percurrently. Conidia cylindrical, broadly rounded at apex, initially somewhat truncate at base, produced deep within the conidiogenous cells, secession rhexolytic, outer wall of conidiogenous cell often remaining on conidium, except at base, eventually disintegrating, olivaceous brown, 3-septate, lightly punctate. Conidia (2–)6.6–10.5(–14) × (1–)2–5(–6) μm (x¯ = 7.3 × 3.6 μmn = 40) brown, smooth-walled or verruculose, aseptate, curved, both sides gradually tapering towards the round to slightly acute apex and truncate base, guttulate. Sexual morph: Not observed.

Material examined: UKRAINE, Donetsk region, Donetsk city, Donetsk Botanical Garden, flowerbed, on dying peduncle stem and live leaves of Yucca filamentosa L. (Asparagaceae), 20 May 2017, Timur S. Bulgakov, DNK-108 (MFLU 17–2529, holotype); ex-type living culture MFLUCC 18-0456

GenBank ITS: ****; LSU: ****.

Notes: Coniothyrium yuccicola is an asexual morph. Conidia of this spcies are brown non-septate, bacilliform, ellipsoid and often thick-walled. Four Coniothryrium species are recorded on Yucca sp. in the world (Farr and Rossman 2021). Coniothryrium bartholomaei and C. herbarum from USA and C. yuccae from Argentina. Coniothyrium concentricum has reported from Bulgaria, China, Cuba, Korea, Netherlands, Poland and USA. These records are mainly based on morphological characteristics. Coniothyrium bartholomaei was report from leaf spot of disease of Yucca in Oregan (USA) (Pscheidt & Ocamb 2018). Microsphaeropsis concetricum was also report form Yucca and known from Ukraine, Russia and former Soviet Union. Phaeosphaeriopsis yuccae is the closet genus of Coniothyrium reported from live leaves of Yucca from Russia.

Coniothyrium yuccicola (MFLU 17–2529, holotypea Specimen with conidiomata b Black acervuli c Brown setae d Conidiophores with basal parts of setae e Hyaline conidiogenous cells f Conidiomata on PDA g Hyaline conidia h Germinating conidium i Appressoria j Reverse view of the colony k Upper view of the colony. Scale bars: b = 200 μm, c = 20 μm, d = 15 μm, e, f = 10 μm g-i = 5 μm