Phytophthora abietivora

Name and publication

Phytophthora abietivora D.W. Li, N.P. Schultes, J. A. LaMondia, R. S. Cowles (2019)

Li DW, Schultes NP, LaMondia JA, Cowles RS. 2019. Phytophthora abietivora, a new species isolated from diseased Christmas trees in Connecticut, USA. Plant Disease 18 (103): 3057–3064.





Latin, abies, referring to conifer genus Abies and -vora, ones that eat


Type: USA, Connecticut, Brooklyn, Allen Hill Farm (41°45.997′N 71°55.182′W), from infected root of a Christmas tree of Abies fraseri (Pursh) Poir., 10 October 2017, R.S. Cowles, UAMH 12075 (RC2017-1). Holotype specimen is a living specimen being maintained via lyophilization at UAMH Centre for Global Microfungal Biodiversity, The Gage Research Institute, Toronto, Canada.

Ex-type: culture NRRL66892

Sequences for ex-type in original manuscript:  ITS MK163944, cox1 MK164270, β-tubulin MK164274, nadh1 MK164269, hsp90 MK164275

Molecular identification

Position in ITS phylogenetic tree

Clade 7a

Morphological identification

Colonies and cardinal temperatures

No information on morphology or cardinal temperature in manuscript.

Conditions for growth and sporulation

Sporangia produced on 10% V8A agar plates flooded with root extract at 15°C under fluorescent light for 7 days. Oogonia are formed readily on V8A.

Asexual phase

Sporangia were non-papillate, non-caducous and predominantly ovoid in shape with internal nested proliferation. Sporangia averaged 33.5 x 25.1 µm (overall range 27.1–41.8 x 17.1–30.8 µm). Sporangiophores unbranched. Hyphal swellings present. Chlamydospores present.

Sexual phase

Homothallic. Oogonia size ranged from 32.1–55.5 µm. Oospores plerotic to slightly aplerotic, thick-walled, size ranged 26.5–42.5 µm. Oospores often aborted after formation of the walls. Antheridia paragynous.

Most typical characters

Phytophthora abietivora produced large oospores with thick walls which differentiate it from related species, P. flexuosa and P. europea.

Hosts and distribution

Distribution: USA; Connecticut
Substrate: roots
Disease note: root rot of young Abies fraseri
Host: Abies fraseri

Additional references and links

none available

Fact sheet author

Treena Burgess, Ph.D., Phytophthora Science and Management, Harry Butler Institute, Murdoch University