Phytophthora pseudorosacearum

Name and publication

Phytophthora pseudorosacearum Burgess (2018) 

Burgess TI, Simamora AV, White D, Wiliams B, Schwager M, Stukely MJC, and Hardy GE StJ. 2018. New species from Phytophthora Clade 6a: evidence for recent radiation. Persoonia 41: 1–17.

Corresponding author: ​


from Burgess et al. (2018)




refers to close relationship to Phytophthora rosacearum


Type: AUSTRALIA, Western Australia, Jarrahdale, from rhizosphere soil of dying Persoonia longifolia, isolated by the VHS, 2013 (holotype MURU 478, dried culture on V8A, Herbarium of Murdoch University, Western Australia)

Ex-type: CBS 143061 and VHS 29592

Sequences for ex-type in original manuscript: as Phytophthora aff. rosacearum strain VHS 29592 = ITS KJ372267;  Phytophthora pseudorosacearum strain VHS 29592 = TUB MF326827, HSP MF326878, COX MF326858 and NADH MF326907

Ex-type in other collections

CBS 143061 = VHS 29592

Molecular identification

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

Phytophthora pseudorosacearum isolate VHS 29592 ITS rDNA KJ372267

Phytophthora pseudorosacearum isolate CPHST BL 188 (= VHS 29592) COI MH477757

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

Clade 6a

Morphological identification

Colonies and cardinal temperatures

Colony morphology on V8 agar, CA, and PDA was cottony with a slight petaloid pattern, growth was appressed with striations on MEA. Minimum growth temperature 4°C, optimum 30°C, and maximum 37.5°C.

Conditions for growth and sporulation

Sporangia are produced in water cultures (soil extract or river water) and not observed in solid media. Oogonia are formed readily in single-strain culture on CA and V8 after about 14 d.

Asexual phase

Sporangia nonpapillate, persistent, and predominantly ovoid to elongated ovoid in shape. Sporangia average 52.7 ± 10.0 x 34.1 ± 5.6 µm (overall range 32.7–59.3 x 19.4–38.3 µm). Sporangiophores simple with internal proliferation both nested and extended. Hyphal swellings predominantly spherical, 6.1–30.9 µm in diameter. Chlamydospores present averaging 28.4 ± 5.3 µm in diameter.

Sexual phase

Homothallic. Oogonia with wavy walls and sometimes a tapering base, average size 35.8 ± 4.9 µm (23.8–49.0). Oospores aplerotic, globose to eccentric turning golden brown on maturity, average size 30.8 ± 3.3 µm (22.3–38.1). Antheridia paragynous.

Most typical characters

Phytophthora pseudorosacearum closely resembles Phytophthora rosacearum, Phytophthora condilina, and Phytophthora kwongonina. Its most distinguishing characteristic is the presence of chlamydospores.

Specimen(s) evaluated

Australia, Western Australia, Jarrahdale, from rhizosphere soil of dying Persoonia longifolia, isolated by the VHS, 2013 CBS 143061 = VHS 29592; Cooljarloo, from water baiting in native vegetation, 1998, R. Hart, HSA2350; Albany, from rhizosphere soil of dying Xanthorrhoea platyphylla, 2010, VHS, VHS 24266

Hosts and distribution

NOT FOUND as of June 2018 in U.S. National Fungus Collections Nomenclature Database.

Additional references and links

  • Phytophthora DATABASE: Phytophthora pseudorosacearum
  • EPPO-Q-bank: Phytophthora pseudorosacearum
  • SMML USDA-ARS: Phytophthora pseudorosacearum
  • EPPO Global Database: Phytophthora pseudorosacearum
  • CABI Invasive Species Compendium: Phytophthora pseudorosacearum
  • Encyclopedia of Life (EOL): Phytophthora pseudorosacearum
  • Index Fungorum (IF): Phytophthora pseudorosacearum
  • Plantwise Knowledge Bank: Phytophthora pseudorosacearum

Fact sheet authors

Treena Burgess, Ph.D., Centre for Phytophthora Science and Management, School of Biological Sciences and Biotechnology, Murdoch University, Australia; Z. Gloria Abad, Ph.D., USDA-APHIS-PPQ-S&T Beltsville Laboratory , United States of America