Phytophthora acerina

Name and publication

Phytophthora acerina Ginetti, Jung, Cooke, Moricca (2014)

Ginetti B, Moricca S, Squires J, Cooke D, Ragazzi A, Jung T. 2014. Phytophthora acerina sp. nov., a new species causing bleeding cankers and dieback of Acer pseudoplatanus trees in planted forests in Northern Italy. Plant Pathology 63: 858–876.

Corresponding author:


from Ginetti et al. (2014)




refers to Acer pseudoplatanus from which all studied isolates had been isolated


Type: ITALY, Boscoincittà Park, Milan, isolated from bleeding bark canker of Acer pseudoplatanus, 2010, B. Ginetti (isolate B057) FI AGR 057 (dried culture on V8A at herbarium of the Museum of Natural History of the University of Florence, Italy)

Ex-type: cultures CBS 133931 = B057

Sequences for ex-type: Phytophthora acerina B057 = ITSrDNA JX951285, β-tubulin KC201283, COI KC156134

Ex-type in other collections

CBS 133931 = B057 = P19934 (WPC), CPHST BL 114 (Abad), 61H1 (Yang)

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of the ex-type (see Molecular protocols page)

Phytophthora acerina isolate CPHST BL 114 (= P19934 WPC) = ITS rDNA MG518642, COI MH136845

Sequences for ex-type in other sources
Position in ITS phylogenetic tree

Clade 2c

Morphological identification

adapted from Ginetti et al. (2014)

Colonies and cardinal temperatures

Colony morphology after 7 days of growth in V8-A is a chrysanthemum pattern, on PDA rosette (petaloid), and on MEA stellate. Minimum growth temperature 6°C, maximum 32°C, and optimum 25°C.

Conditions for growth and sporulation

Hyphal swellings produced in ageing cultures (3–6 weeks old) and in nonsterile pond water.

Asexual phase

Sporangia semipapillate, rarely bi- or tripapillate; persistent; ovoid, limoniform, obpyriform, ellipsoid, elongated, obovoid, mouse-shaped, and with distorted shapes (20–105 L x 11–51 W μm); originated on unbranched sporangiophores. Hyphal swellings subglobose or irregular, sometimes catenulate, infrequently formed on sporangiophores. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia smooth-walled; globose, subglobose, or elongated (28–36 μm diam); antheridia paragynous; globose, obovoid, club-shaped or irregular, sometimes with a finger-like projection and usually attached close to the oogonial stalk; oospores pleroticglobose or subglobose in elongated oogonia (24–32 μm) with medium wall thickness (1.8–2.4 μm).

Most typical characters

Besides the characters mentioned above, the species is characterized by the presence of a high oospore abortion rate of 40–96% and the abundant production of dense stromata-like hyphal aggregations.

Additional specimen(s) evaluated

Phytophthora acerina CPHST BL 114 (Abad) = P19934 [World Phytophthora Collection (WPC) California, USA] duplicate of the ex-type CBS 133931

Hosts and distribution

Distribution: Europe (Italy)
Substrate: collar, stems
Disease note: collar rot, bleeding canker, crown dieback, death
Host: Acer pseudoplatanus (Sapindaceae)

Retrieved January 17, 2018 from U.S. National Fungus Collections Nomenclature Database.

Additional references and links

Fact sheet author

Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory, United States of America