Pseudocercospora rauvolfiicola A. Singh, P. N. Singh and N. K. Dubey 2022, sp. nov.

Pseudocercospora rauvolfiicola A. Singh, P.N. Singh and N.K. Dubey sp. nov. Fig 1–4

MycoBank: MB 834637

Etymology. Name refers to Rauvolfia, the host genus from where the fungus was isolated.

Culture characteristics – Colonies after 21 days at 27 ° C on Oat Agar (OA) blackish grey, velvety, mycelium sparse, sulcate, reverse blackish grey reaching 30 mm diameter. On Potato Dextrose Agar (PDA) erumpent in centre, margin lobed, grayish black, velvety, reverse black, upto 16 mm.

Pathogen on Rauvolfia serpentina Leaf spots dark blackish brown with yellowish encircling area on the upper leaf surfaces, grayish brown on lower surfaces, circular to irregular. Caespituli hypophyllous, substomatal. Mycelium internal, branched. Asexual morph: Stromata substomatal, pseudoparenchymatous, light yellowish brown to light brown, globular, few cells to 13 µm filling stomatal opening, Conidiophores 14–35.5 × 2–3 µm (x̅= 24×3, n=40) macronematous, mononematous, olivaceous brown to light brown, paler towards the tip, fasciculate in divergent fascicles (up to 14), smooth, 0–3 septate, branched, straight to curved, geniculate, sub cylindrical. Conidiogenous cells polyblastic, integrated, terminal, pale olivaceous, smooth, geniculate, scar unthickened. Conidia 9.5–56.5 × 2–3.5 µm (x̅= 36×3 µm, n =40), solitary to branched in chains, acropleurogenous, holoblastic, pale brown, subcylindrical to obclavate, apex obtuse to subacute, base obconico truncate, ramoconidium present, straight to curved, 1–5 septate, hilum unthickened.

Type. India, Uttar Pradesh, Sonebhadra, leaf spots on Rauvolfia serpentina (L.) Benth.ex Kurz (Apocynaceae), 15 Dec. 2019, Archana Singh, AMH-10139 (Holotype), BHUAS/19/23 (Isotype), NFCCI 4586 (ex-type living culture), ITS, LSU, ACT and TEF sequences GenBank MT068200.1, MT102882.1, MW496125, MW496126.