What is Sudden Oak Death?

Sudden Oak Death is a tree disease caused by the plant pathogen Phytophthora ramorum. The disease kills some oak species and has had devastating effects on forests in California and Oregon. Read more about Sudden Oak Death.

Areas of Interest

P. ramorum in Wildlands The information in this section is geared toward land management, forestry and arboriculture professionals, including Best Management Practices.
P. ramorum in Nurseries This section addresses P. ramorum issues critical to nurseries, independent growers, and related plant-care/plant propagation industries, including Nursery Diagnostic Guides.
P. ramorum
in the Urban Interface
Look here for resources that address common homeowner questions, including diagnosing Sudden Oak Death and finding an arborist to work with.


The California Oak Mortality Task Force is a task force under the California Forest Pest Council.



National forest sampling in 2014 identifies new P. ramorum-positive waterways. Read more…

Larch infestations in the UK reduced significantly in 2014. Read more…

Shrub tanoak confirmed as a P. ramorum host. Read more…

Resources on P. tentaculata, recently found in native plant nurseries and restoration sites.

New THANQs – FAQ Resource for Tree Health Questions

Read the latest newsletter.

Help stop the spread of forest pests – including Sudden Oak Death – on firewood! Check out the website of the California Firewood Task Force.

Calendar of Events

3/6Trinity County SOD Blitz Training; Weaverville

3/24 – 3/26 – Meeting of the 61st Annual Conference on Soilborne Plant Pathogens (formerly Soil Fungus Conference) and the 47th Annual California Nematology Workgroup; UC Riverside

4/10 – Santa Cruz SOD Blitz Training; UC Santa Cruz Botanic Garden

4/11 – East Bay (Orinda) SOD Blitz Training; Orinda Library Garden Room

See the entire events calendar.