Phytophthora ilicis (to be redescribed 2022)

Name and publication

Phytophthora ilicis Buddenhagen & Young (1957)

Buddenhagen IW and Young RA. 1957. A leaf twig disease of English holly caused by Phytophthora ilicis n.sp. Phytopathology 47: 95–101.





from Buddenhagen and Young (1957)

Type: UNITED STATES OF AMERICA, Oregon, from leaves and stems of Ilex aquifolium L. collected on November 1954

Ex-type: LOST

Well-authenticated specimen selected by Gloria Abad: 
CPHST BL 39 = P3939 WPC, from Ilex aquifolium, CANADA
CPHST BL 103 = P6099 WPC, from Ilex aquifolium, UNITED STATES OF AMERICA

Selected specimen(s) in other collections

CPHST BL 39 (Abad) = P3939 WPC = ATCC 56615, MYA-3897, P113, Ho 18.1, 23A7 (Yang)

CPHST BL 103 (Abad) = P6099 WPC 

Molecular identification

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

Phytophthora ilicis isolate CPHST BL 39 (= P3939 WPC) = ITS rDNA MG865511, COI MH136905
Phytophthora ilicis isolate CPHST BL 103 (= P6099 WPC) = ITS rDNA MG865510, COI MH136904

Sequences for ex-neotype in other sources
Position in phylogenetic tree

Clade 3a

Morphological identification

Colonies and cardinal temperatures

Colony morphology in V8-A and PDA with light stellate pattern, in MEA with slow growth. The minimum temperature for growth is 5°C, optimum 20°C, and maximum 25°C.

Conditions for growth and sporulation

Sporangia produced after mats growing in pea broth are transfered to water cultures and incubated for 5 days at 20°C.

Asexual phase

Sporangia nonpapillate and semipapillate; sometimes caducous with medium to long pedicels (5–25 μm); ovoid, obpyriform (25–45 μm long x 15–28 μm wide); originated in unbranched or in simple sympodial sporangiophores. Hyphal swellings absent. Chlamydospores rare.

Sexual phase

Homothallic. Oogonia smooth-walled (25–35 μm diam.), presenting tapered bases; antheridia amphigynous; oospores plerotic and aplerotic.

Specimen(s) evaluated

Phytophthora ilicis CPHST BL 103 = P6099 (World Phytophthora Collection)

Phytophthora ilicis CPHST BL 39 = P3939 (World Phytophthora Collection)

Hosts and distribution

Distribution: Europe (Italy, France, UK), North America (Canada, USA)
Substrate: leaves, twigs
Disease note: leaf and twig blight, bleeding canker
Host: Ilex aquifolium, Ilex spp. (Aquifoliaceae)

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

Additional references and links

Phytophthora ilicis in OSU Phytophthora Online course: Training for Nursery Growers. Oregon State University.

Fact sheet author

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