Pseudocercospora trifoliorum S. Rajwar, Raghv. Singh & Sham. Kumar, 2025

Pseudocercospora trifoliorum S. Rajwar, Raghv. Singh & Sham. Kumar , sp. nov. ( Figs. 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )

MycoBank number: MB 849773

Diagnosis:— Differs from P. gangetici which develops shorter and wider conidiophores from secondary superficial hyphae and, in addition, has stromata and larger conidia with more septa. Moreover, most conidia are guttulate in P. trifoliorum .

Etymology:— trifoliorum derived from the name of host species.

Type:— INDIA. Uttar Pradesh: Varanasi, BHU campus, 25°16’4.3608’’N 82°59’25.7784’’ E, 4 December 2021, Soumyadeep Rajwar, on living leaves of Grona triflora ( L.) H. Ohashi & K. Ohashi ( Fabaceae ), AMH 10471 (holotype), MH-BHU 71 (isotype), NFCCI 5321 (ex-type living culture).

Infection spots amphigenous, light brown to brown, vein limited, 0.5–1 mm diam., later coalescing to cover entire surface of leaves. Sexual morph: not seen. Asexual morph: Colony amphiphyllous. Mycelium internal. Stromata poorly developed, sub-epidermal to mostly erumpent, pseudoparenchymatous, mid-brown to dark brown, 7–18 × 5–15 µm. Conidiophores macronematous, mostly mononematous, rarely fasciculate, arising from stromata, light olivaceous brown to mid brown, simple to rarely branched, cylindrical, erect to procumbent, 0–22-septate, wall smooth to minutely roughened, faintly thickened, basal cell globose, 40–305 × 2.5–5.5 µm. Conidiogenous cells integrated, terminal to intercalary, mono- to polyblastic, geniculate, light olivaceous brown to mid brown, 12–27 × 2.5–5.5 µm, loci unthickened and undarkened, 1.7–4.2 µm wide. Conidia solitary, olivaceous to olivaceous-brown, simple, dry, guttulate, smooth or finely roughened, thin-walled, oval to elliptical, cylindrical to fusiform, straight to slightly curved, obclavate to obclavate-cylindrical, base rounded to truncate, apex mostly obtuse, 16–40 × 2.5–6.5 µm, 0–3-septate, sometimes constricted at septa, hila unthickened and undarkened, 1.5–2 µm wide.

Description in vitro

Initially only sterile mycelium was found without development of any kind of fruiting body or spores, later developing oval to spherical or barrel-shaped chlamydospores. These chlamydospores are olivaceous to light olivaceous brown, measuring 8–13 × 5–13 µm ( Fig. 1k–m View FIGURE 1 ).

Culture characteristics

Colonies on PDA, reaching 1.7 cm in diameter after 30 days at 25±5 ° C. Whitish-grey with a dark black, velvety reverse, margin irregular, with a surface that is both folded and raised, with dense cottony mycelium ( Fig. 1h, i View FIGURE 1 ).