Phytophthora virginiana

Name and publication

Phytophthora virginiana Yang & Hong (2013)

Yang X and Hong C. 2013. Phytophthora virginiana sp. nov., a high-temperature tolerant species from irrigation water in Virginia. Mycotaxon 126: 167–176.

Corresponding author:


from Yang and Hong (2013)


MB 804533


refers to the Commonwealth of Virginia, where the new species was initially recovered


Type: UNITED STATES OF AMERICA, Virginia, baited with camellia leaves from irrigation water of an irrigation runoff reservoir in a production perennial nursery, October 2007, collected by Chuanxue Hong; holotype, ATCC MYA-4927

Ex-type: 46A2

Sequences for ex-type in original manuscript: Phytophthora virginiana isolate 46A2 = ITS rDNA KC295544

Ex-type in other collections

46A2 (Yang) = ATCC MYA-4927, P19829 (WPC), CPHST BL 165 (Abad)

Molecular identification

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

Phytophthora virginiana isolate 46A2 ITS rDNA KC295544

Phytophthora virginiana isolate CPHST BL 165 (= P19829 WPC) COI MH477761

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

Clade 9a

Morphological identification

adapted from Yang and Hong (2013)

Colonies and cardinal temperatures

Colonies on V8-A, PDA, and MEA with chrysanthemum pattern.

Conditions for growth and sporulation

Sporangia produced in culture plugs submerged in 1.5% soil water extract under light within 10 hours.

Asexual phase

Sporangia nonpapillate, persistent, ovoid to obpyriform and sometimes limoniform to ellipsoid with distorted shapes such as peanut (av. 51.7 x 32.5 µm), showing internal, nested or extended proliferation, and borne in erect, unbranched sporangiophores with occasional swelling. Hyphal swellings common, often peanut-shaped, angular, or variously distorted in shapes. Chlamydospores abundant, thin-walled, spherical, and lateral produced by mature cultures, av. 43.5 µm diam, sometimes on short stalks, with tapered base or clustered. Terminal chlamydospores rare.

Sexual phase

Self-sterile. No sexual organs in single cultures. In the polycarbonate membrane tests, P. virginiana isolates belong to silent A1 mating type, producing no sexual organ after up to 90-day-pairing, but stimulating A2 mating type isolates of Phytophthora cinnamomi and Phytophthora cryptogea to produce gametangia after 30-day-pairing at 20°C, 25°C, and room temperature (c. 23°C).

Additional specimen(s) evaluated:

Phytophthora virginiana ex-type CPHST BL 165, duplicate of P19829 (World Phytophthora Collection)

Hosts and distribution

Distribution: North America (USA: VA)
Substrate: isolated from irrigation water
Host:  unknown

Retrieved February 01, 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