Phytophthora fragariae (to be redescribed 2022)

Name and publication

Phytophthora fragariae Hickman (1940)

Hickman CJ. 1940. The red core root disease of strawberry caused by Phytophthora fragariae n. sp. J. Pomol. Hortic. Sci. 18: 89–118 (pg. 103).





from Hickman (1940)

Type: ENGLAND, causing red core root disease of strawberry in Westerham Hill, Kent collected in October 1938 by C. J. Hickman

Ex-type: LOST

Well authenticated specimen(s) selected by Gloria Abad: 

CPHST BL 18 = P19539 (WPC) from Fragaria x ananassa, ENGLAND

P10752 (WPC) from Fragaria x ananassa, UNITED STATES OF AMERICA (NCBI ITS rDNA sequence FJ801504)

Selected specimen in other collections

CPHST BL 18 (Abad) = P19539 (WPC) = P6231 (WPC) = CBS 209.46, IMI 181417, 61J3 (Yang)

Molecular identification

Voucher sequences for barcoding genes (ITS rDNA and COI) of selected specimen (see Molecular protocols page)

Phytophthora fragariae isolate CPHST BL 18 (= P19539 WPC) = ITS rDNA MG865494, COI MH136890

Sequences for selected specimen in other sources
Position in ITS phylogenetic tree

Clade 7a

Genome sequence

Phytophthora fragariae strain ex-epitype CBS 309.62. Accession genome P.fr2.0, BioProject PRJNA243070, Shenzhen Entry-Exit Inspection and Quarantine Bureau (2018), Gao et al. 2015

Morphological identification

Colonies and cardinal temperatures

Colony morphology after 7 days on CMA, PDA, V-8, with no distinct pattern. Minimum growth temperature 3°C, optimum 18°C, and maximum 27°C.

Asexual phase

Sporangia nonpapillate; persistent; obpyriform, ovoid, ellipsoid (28–56 L x 27–49 W µm), often very markedly obpyriform in shape; with internal and nested proliferation and originated in unbranched or simple sympodial sporangiophores. Hyphal swellings globose, subglobose, coralloid, solitary, and catenulate in chains. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia smooth-walled, originated in very short stalks; frequently globose (28–46 µm diam) with tapering base; antheridia paragynous or amphigynous (16–30 L x 12–22 W µm); oospores spherical (24–44 µm diam), ellipsoidal, or irregular.

Specimen(s) evaluated

Phytophthora fragariae CPHST BL 18, duplicate of P19539 (World Phytophthora Collection)

Phytophthora fragariae P10752 (WPC) 

Hosts and distribution

Distribution: Asia, Australia, New Zealand, Europe, North America (Canada, USA)
Substrate: roots
Disease note: Red stele or red core root rot. The most important fungal pathogen of strawberries (Ho & Jong 1988). Foreign races are listed by APHIS as a regulated plant pest.
Host: Fragaria x ananassa and Rubus ursinus var. longanobaccus (Rosaceae) are the only known hosts under natural conditions. Infection of other Rosaceae, Amaranthaceae, and Solanaceae can occur via artificial inoculation (Erwin 1996).

Retrieved January 30, 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