Cercospora arachidicola Hori, Rep. (Annual) Nishigahara Agric. Exp. Sta. Tokyo: 26. 1917.

Japan. Tokyo, Experiment Station, on Arachis hypogaea (Fabaceae), (no date), S. Hori. s.n. (Holotype HIRO, n.v.).

For more synonyms see Crous and Braun (2003) or MycoBank.

Leaf spots amphigenous, subcircular to angular-irregular, 2.5–9.5 mm diam., greyish brown to medium dark brown, occasionally limited by veins, margin indefinite. Caespituli epiphyllous, whitish brown to greyish brown. Mycelium mainly internal. Internal hyphae pale brown, smooth, 1.5–3 μm wide. Stromata small, up to approx. 32 μm diam., embedded in the mesophyll or in substomatal chambers, subcircular to irregular, brown to dark brown. Conidiophores in small, loose to moderately dense fascicles, arising from internal hyphae or stromata, or solitary, arising through stomatal openings, erect, straight to sinuous or geniculate, simple, (11.5–)14–42.5(–53) × (3.5–)4–5 μm, 0–5-septate, smooth, olivaceous brown to slightly dark brown, paler towards the tips. Conidiogenous loci 2–2.5(–3) μm wide, thickened and darkened. Conidia solitary, narrowly obclavate to subacicular, straight to slightly curved, (16–)23–76.5(–88) × 3.5–4.5 μm, 2–5-septate, olivaceous brown, apex subacute or acute, base truncate to short obconically truncate, 2–2.5(–3.5) μm wide, hila thickened and darkened.

Benin. Donga: Taneka-Koko, c. 441 m a.s.l., 9°51'30"N, 1°29'34"E, on Arachis hypogaea, 29 Jul 2017, Y. Meswaet, M. Piepenbring, N. S. Yorou and participants of the summer school 2017, YMM49B (M-0312666; UNIPAR). Benin. Borgou: Parakou, c. 354 m a.s.l., 9°20'02"N, 2°38'48"E, same host, 27 Aug 2019, Y. Meswaet and R. Dramani, YMM224B (M-0312667).

Passalora arachidicola. On Arachis sp.: Guinea. Labe, 29 Jul 1964, Litzenberger S. C. 55 (BPI 432987 as Cercospora arachidicola). On Arachis sp.: Guinea. Dubreka, 25 Jul 1964, Litzenberger S. C. 39 (BPI 432989 as C. arachidicola). On Arachis sp.: Guinea. Beyla, 2 Aug 1964, Litzenberger S. C. 47 (BPI 432990A as C. arachidicola). On Arachis sp.: Guinea. Kissidougou, 4 Aug 1964, Litzenberger S. C. 28 (BPI 432991 as C. arachidicola). On Arachis sp.: Guinea. Dabola, 4 Aug 1964, Litzenberger S. C. 26 (BPI 432992 as C. arachidicola).

On Arachis hypogaea (Fabaceae) known worldwide where the host is cultivated, including Afghanistan, Angola, Argentina, Australia, Bangladesh, Benin, Bolivia, Brazil, Brunei, Burkina Faso, China, Cuba, Cambodia, Cameroon, Colombia, Comoros, Democratic Republic Congo, Cuba, Dominican Republic, El Salvador, Fiji, Gabon, Gambia, Ghana, Guatemala, Guinea, Guyana, Hong Kong, India, Indonesia, Ivory Coast, Jamaica, Japan, Kenya, Korea, Laos, Lebanon, Libya, Madagascar, Malawi, Malaysia, Mali, Mauritius, Mexico, Mozambique, Myanmar, Nepal, New Caledonia, Nicaragua, Niger, Nigeria, Pakistan, Panama, Papua New Guinea, Philippines, Puerto Rico, Malaysia, Senegal, Sierra Leone, Solomon Islands, Somalia, South Africa, Sudan, Suriname, Taiwan, Tanzania, Thailand, Togo, Uganda, USA, Uruguay, Venezuela, Vietnam, Zambia, Zimbabwe (Chupp 1954; Hsieh and Goh 1990; Shin and Kim 2001; Crous and Braun 2003; Farr and Rossman 2021).

Passalora arachidicola was placed into the genus Passalora by Braun (1999) based on morphological characteristics that are confirmed in the context of the present study. Crous et al. (2009b, 2009c, 2013a) showed that the genus Passalora is paraphyletic or polyphyletic. Therefore, the present species most probably does not belong to Passalora. However, we refrain from drawing taxonomic conclusions here because a revision of the genus Passalora is beyond the scope of the present study.