Fungalpedia – Note 126 Allophoma


Allophoma Qian Chen & L. Cai

Citation when using this entry: Aumentado et al. in prep – Fungalpedia, plant pathogens. Mycosphere. 

Index FungorumFacesoffungiMycoBankGenBank

Ascomycota, Pezizomycotina, Dothideomycetes, Pleosporomycetidae, Pleosporales, Didymellaceae

Allophoma was recognized by Chen et al. (2015) with A. tropica as the type species based on morphological characteristics and phylogenetic studies. Allophoma was introduced to encompass a novel species and five species previously included in Phoma with various shaped conidia (Chen et al. 2015). There are 14 established species identified through morpho-molecular data analysis employing genetic markers such as the internal transcribed spacer (ITS) region and the 28S large ribosomal subunit RNA (LSU) gene and protein-coding genes: beta-tubulin (β-tub), and RNA polymerase II second largest subunit (rpb2) gene regions (Chen et al. 20152017Valenzuela-Lopez et al. 2018Babaahmadi et al. 2018Marin-Felix et al. 2019Jayasiri et al. 2019, Huo et al. 2020Yuan et al. 2021). 

Allophoma is characterized by its ovoid, oblong, aseptate conidia which can be ellipsoidal to cylindrical, or somewhat allantoid (Chen et al. 2015). The conidiomata are pycnidial and can be globose to flask-shaped. Conidiomata are found either on the surface of agar or submerged in it. The pycnidial wall consists of pseudoparenchymatous tissue, typically composed of 2 to 5 cell layers. The conidiogenous cells are phialidic, hyaline, and smooth. Conidiogenous cells are ampulliform, doliiform, flask-shaped, or isodiametric. The conidia are hyaline, thin-walled, smooth, and aseptate. These conidia vary in both shape and size as some are ovoid, oblong, ellipsoidal to cylindrical, or somewhat allantoid, and often contain guttules (Chen et al. 20152017).

Several species of Allophoma are important phytopathogens, causing various plant diseases such as leaf spot, necrosis, canker, seed rot, and dieback to various plant species. i.e., Lantana camara, Lactuca sativa, Euphorbia milii, Solanum lycopersicum, Citrullus colocynthis, Cucurbita pepo, and Syzygium cumini (Farr & Rossman, 2023). Disease symptoms include leaf lesions that are dispersed, irregularly shaped, and clearly defined and can be found both on the upper surface and underside of the leaf (Yuan et al. 2021). On the stem, it appears as spots that can rapidly develop to a soft, black cortical rot whereas portions of the stem that did not exhibit any symptoms remained intact without any signs of decay (O’Neill & Mayne 2016). Pathogenic species of Allophoma include A. zantedeschiae (Boerema 1993), A. piperis (Boerema et al. 2004), A. labilis (O’Neill & Mayne 2016Nagarjun & Suryanarayana 2016Keshavarzi et al. 2023Demir et al. 2023), A. tropica (Schneider & Boerema 1975Boerema et al. 2004Zimowska 2011Gilardi et al. 2018) and A. hayatii (Babaahmadi et al. 2018). Whereas the recently introduced species A. thunbergiae causes leaf spots of Thunbergia grandiflora (Yuan et al. 2021). Pathogenicity studies have been conducted on Syzygium cumini (Nagarjun & Suryanarayana 2016), Solanum lycopersicum resulting in stem girdling (O’Neill & Mayne 2016), Cucurubita pepo seeds inciting seedling root and crown rot (Demir et al. 2023), and Lantana camara stems causing external longitudinal necrosis in the bark, and cracking of the stem cortex (Babaahmadi et al. 2018). 

Type species: Allophoma tropica (R. Schneid. & Boerema) Qian Chen & L. Cai

For other species: Species Fungorum, search Allophoma for names     



Babaahmadi G, Mehrabi-Koushki M, Hayati J. 2018 – Allophoma hayatii sp. nov., an 

undescribed pathogenic fungus causing dieback of Lantana camara in Iran. Mycological Progress 17, 365–379.

Boerema GH. 1993 – Contributions towards a monograph of Phoma (Coelomycetes), ii. section 

peyronellaea. Persoonia 15, 197–221.

Boerema GH, de Gruyter J, Noordeloos ME, Hamers MEC. 2004 – Phoma identification manual. 

Differentiation of specific and infra‐specific taxa in culture. Wallingford, UK: CABI Publishing.

Chen Q, Jiang JR, Zhang GZ, Cai L et al. 2015 – Resolving the Phoma enigma. Studies in 

mycology 82, 137–217.

Chen Q, Hou LW, Duan WJ, Crous PW et al. 2017 – Didymellaceae revisited. Studies in 

Mycology 87(1), 105–159.

Demir E, Özer N, Bayraktar H. 2023 – Identification of seed-borne fungi in summer (Cucurbita 

pepo) and winter (Cucurbita moschata) pumpkins of Turkey. Journal of Plant Pathology 1–5.

Farr DF, Rossman AY. 2023 – Fungal databases. U.S. National Fungus Collections, ARS, USDA.

Gilardi G, Gullino ML, Garibaldi A. 2018 – Emerging foliar and soil‐borne pathogens of leafy 

vegetable crops: a possible threat to Europe. EPPO Bulletin 48(1), 116–127. 

Hou LW, Groenewald JZ, Pfenning LH, Yarden O et al. 2020 – The phoma-like dilemma. Studies 

in Mycology 96, 309–396.

Jayasiri SC, Hyde KD, Jones EBG, McKenzie EHC et al. 2019 – Diversity, morphology and 

molecular phylogeny of Dothideomycetes on decaying wild seed pods and fruits. Mycosphere 10,1–186.

Keshavarzi F, Farrokhinejad R, Mehrabi-Koushki M. 2023 – Identification of Didymellaceae 

fungi associated with different disease symptoms in some medicinal plants of Khuzestan Province, Iran. Iranian Journal of Plant Protection Science 53(2), 163–176.

Marin-Felix Y, Hernández-Restrepo M, Iturrieta-González I, García D et al. 2019 – Genera of 

phytopathogenic fungi: GOPHY 3. Studies in mycology 94, 1–124.

Nagarjun N, Suryanarayana V. 2016 – Documentation, characterization and management of leaf 

spot of Syzygium cumini (L.) Skeels. Journal of Pharmaceutical Sciences 29, 381–385.

O’Neill T, Mayne S. 2016 – An Unusual Phoma stem rot of tomato. AHDB Horticulture, 

Factsheet 06/16.

Schneider R, Boerema GH. 1975 – Phoma tropica n. sp, ein an Gewächshauspflanzen häufig 

vorkommender, nicht pathogener Pilz. Phytopathologische Zeitschrift 83, 360–366.

Valenzuela-Lopez N, Cano-Lira JF, Guarro J, Sutton DA et al. 2018 – Coelomycetous 

Dothideomycetes with emphasis on the families Cucurbitariaceae and Didymellaceae. Studies in mycology 90(1), 1–69.

Yuan J, Zeng XY, Geng K, Wijayawardene NN et al. 2021 – Allophoma species (Pleosporales: 

Didymellaceae) associated with Thunbergia grandiflora in Guangxi Province, China. Biodiversity Data Journal 9.

Zimowska B. 2011 – Characteristics and occurrence of Phoma spp. on herbs from the family 

Lamiaceae. Acta Scientiarum Polonorum, Hortorum Cultus 10 (2).


Entry by

Herbert Dustin R. Aumentado, Center of Excellence in Fungal Research and School of Science, Mae Fah Luang University, Chiang Rai, Thailand 


Edited by Ruvishika S. Jayawardena & Kevin D. Hyde