Phytophthora idaei

Name and publication

Phytophthora idaei Kennedy (1995)

Kennedy DM and Duncan JM. 1995. A papillate Phytophthora species with specificity to Rubus. Mycol. Res. 99: 57–68.


from Kennedy and Duncan (1995)




named for the original host Rubus idaeus


Type: SCOTLAND, isolated from the roots of cultivated raspberries (Rubus idaeus) cv. Malling Leo collected by Kennedy in 1987; holotype: IMI 313728

Ex-type: SCRI R77 (Scottish Crop Research Institute); WPC: P6767, type strain. Received from Phil Hamm in 1989. Collected by D.M. Kennedy, Scottish Crop Research Institute, Invergowrie, Dundee, U.K., (SCRI R77, 1987), Location: UK, Scotland.

Ex-type in other collections

SCRI R77 = P6767 (WPC), CBS 971.95, PD 94/959, ATCC MYA-4065, Duncan SCRI R77, Hamm 816, PD 94/959, David Cooke IDA3, CH 34D4, CPHST BL 38 (Abad), 34D4 (Yang), P220

Molecular identification

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

Phytophthora idaei isolate CPHST BL 38 (= P6767 WPC) = ITS rDNA MG865509, COI MH136903

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

Clade 1a

Morphological identification

Colonies and cardinal temperatures

Colonies with very slow growth and with no obvious pattern in PDA, CMA, and V8A. The minimum temperature for growth is 3°C, optimum 18–24°C, and maximum 27°C.

Asexual phase

Sporangia papillate; persistent; globose, ovoid, ellipsoid (23–56 L x 17–42 W µm), with external proliferation and produced in simple and in irregular lax sympodium sporangiophores. Hyphal swellings absent. Chlamydospores absent.

Sexual phase

Homothallic. Oogonia smooth-walled, spherical (24–44 µm diam) with tapered base and often-comma shaped, and sometimes pigmented when mature; antheridia ellipsoid, ovoid, or club-shaped (13 x 27 µm), predominantly paragynous, and commonly attached near the oogonial stalk; oospores plerotic and aplerotic (24–36 µm diam).

Most typical characters

Phytophthora idaei is characterized by the presence of globose to ovoid persistent sporangia and oogonia with tapered base often comma-shaped.

Specimen(s) evaluated

Phytophthora idaei ex-type CPHST BL 38, duplicate of P6767 (World Phytophthora Collection)

Hosts and distribution

Distribution: Europe (UK)
Substrate: roots
Disease note: root rot. No aerial symptoms were produced when up to 20 percent of roots were infected; potentially spread by cultivation of apparently healthy plants.
Host: Rubus idaeus (red raspberry, Rosaceae)

Retrieved January 31, 2018 from U.S. National Fungus Collections Nomenclature Database.

Quarantine status

USA: This species was listed as a species of concern during the 2009 Phytophthora prioritization project conducted by USDA APHIS PPQ CPHST PERAL (Schwartzburg et al.).

Additional references and links

Fact sheet author

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