Phytophthora lateralis

Name and publication

Phytophthora lateralis Tucker & Milbrath (1942)

Tucker CM and Milbrath JA. 1942. Root rot of Chamaecyparis caused by a species of Phytophthora. Mycologia 34: 94–103.





from Tucker and Milbrath (1942)

Type: UNITED STATES OF AMERICA, Port Orford, Cedar (Chamaecyparis lawsoniana), Oregon, CBS-H-7643

Ex-type: CBS 168.42

Ex-type in other collections

CBS 168.42 = P3361 (WOC/WPC), P3917 (WPC), DSM 62687, IMI 040503, VKM F-1835, IMB 10780, PD 06 03209088, CPHST BL 42 (Abad)

Molecular identification

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

Phytophthora lateralis isolate CPHST BL 42 (= P3361 WPC) = ITS rDNA MG865522, COI MH136917

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

Clade 8c

Genome sequence 

Phytophthora lateralis strain ex-type CBS 168.42. Accession genome ASM50020v2, BioProject PRJNA190827, Tree Aggressors Identification using Genomic Approaches (2016), Feau et al 2016

Morphological identification

Colonies and cardinal temperatures

Colony morphology after 7 days of growth on V8-A and MEA with no distinctive pattern, on PDA coarsely radiate. Minimum temperature for growth is 3°C, optimum 20°C, and maximum 25°C. 

Conditions for growth and sporulation

Sporangia are not produced on agar media, but produced relatively abundantly on washed mycelial mats transferred from 7-day pea broth cultures (20°C) to sterile distilled water and incubated 7 days at 20°C. Chlamydospores abundant in agar cultures and liquid media. 

Asexual phase

Sporangia nonpapillate; persistent; ovoid, obovoid, obpyriform, elongate (24–76 L x 19–41 W µm); originated unbranched in long sporangiophores, by external proliferation and on simple sympodial sporangiophores. Hyphal swellings globose, catenulate, or with irregular shape. Chlamydospores subspherical to spherical, occasionally ovoid to irregular; individual or distant catenulated; lateral, terminal, or intercalary (20–77 µm diam). 

Sexual phase


Note: Original publication of Tucker, C.M.; Milbrath, J.A. 1942 referred to oogonia, antheridia, and oospores as unknown. Isolate of the ex-type CBS 168.42 evaluated by Q-Bank has not produced oospores, and the same results were found for the duplicate of the ex-type CPHST BL 42.

Most typical characters

Phytophthora lateralis can be distinguished by the shape of the sporangia, hyphal swellings, and typical chlamydospores.

Specimen(s) evaluated

Phytophthora lateralis ex-type CPHST BL 42 = P3361 (World Phytophthora Collection), duplicate of ex-type CBS 168.42 

Additional well-authenticated specimens evaluated:
P. lateralis P3888 (World Phytophthora Collection)
P. lateralis P11090 (World Phytophthora Collection)

Hosts and distribution

Distribution: widespread. Reports from New Zealand and North Carolina are doubtful.
Substrate: roots, crown, bark, occasionally on foliage
Disease note: root and crown rot, girdling, death
Host: Chamaecyparis lawsoniana (Lawson cypress aka Port Orford cedar), C. lateralis (Cupressaceae), rarely, Taxus brevifolia (Pacific yew, Taxaceae). Hosts in other families can be infected when inoculated.

Retrieved January 31, 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