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Phytophthora lateralis

A severe root rot disease of Chamaecyparis lawsoniana


NOTE: a full datasheet in being prepared, in the meantime you can view here the data which was previously available from the EPPO Alert List.

Why: Phytophthora lateralis came to our attention during a bibliographic search on sudden oak disease (caused by another Phytophthora species), as significant tree mortality and severe losses are reported in USA on C. lawsoniana growing in nurseries, gardens and forests.

Where: North America: Canada (British Columbia), USA (California, Oregon, Washington).

On which plants: Chamaecyparis lawsoniana. Taxus brevifolia has also been reported as a host plant but it is less susceptible and tree mortality has only been observed in areas where C. lawsoniana trees were also infected.

Damage:Root rot leading to tree mortality.

Transmission:Root contact, zoospores in water, resting spores (chlamydospores) in the soil.

Pathway:Plants for planting and wood of host plants (C. lawsoniana, Taxus brevifolia), infested soil from areas where P. lateralis occurs.

Possible risks:
In the EPPO region, C. lawsoniana is occasionally planted in forests but is a widespread ornamental tree. P. lateralis causes tree mortality in all cases and there is no curative treatment available. It could represent a serious threat, especially for the ornamental plant industry if introduced into the EPPO region. The isolated finding in France also suggests that there is a pathway for introducing the pathogen (may be through contaminated soil attached to C. lawsoniana or other non-host plants).


Hansen, E.M.; Goheen, D.J.; Jules, E.S.; Ullian, B. (2000) Managing Port-Orford-Cedar and the introduced pathogen Phytophthora lateralis.Plant Disease, 84(1), 4-14.
Hansen, E.M.; Streito, J.C.; Delatour, C. (1999) First confirmation of Phytophthora lateralis in Europe. Plant Disease, 83(6), p 587.
Murray, M.S.; Hansen, E.M. (1997) Susceptibility of Pacific Yew to Phytophthora lateralis. Plant Disease, 81(12), 1400-1404.
DeNitto, G.A.; Kliejunas, J.T. (1991) First report of Phytophthora lateralis on Pacific yew. Plant Disease, 75(9), p 968.
Erwin, D.C. Ribeiro, O.K (1996) Phytophthora lateralis. In: Phytophthora diseases worldwide. American Phytopathological Society, St. Paul (US), pp 365-367.
Winton, L.M.; Hansen, E.M. (2001) Molecular diagnosis of Phytophthora lateralis in trees, water, and foliage baits using multiplex polymerase chain reaction. Forest Pathology, 31(5), 275-283.
USDA. Forest Service. Pacific Northwest Region. Ecology and management of Port-Orford-cedar.
USDA. Forest Service. Pacific Northwest Region. Port-Orford-Cedar root disease by Roth, L.W.; Harvey Jr, R.D;; Kliejunas, J.T.

EPPO RS 2001/034, 2001/204

Panel review date -
Entry date 2001-02


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