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.



Results from the 2016 National P. ramorum Early Detection Survey are in from nine eastern states. Read more…

High infection levels found near Mt. Diablo, despite low bay laurel densities. Read more…

Survey says the SOD monitoring and outreach work still very important along California’s north coast. Read more…

Read the latest newsletter.

Resources on P. tentaculata, recently found in native plant nurseries and restoration sites, can be found on the new CalPhytos.org web page.

New THANQs – FAQ Resource for Tree Health Questions

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

3/19 – 3/25 – 8th Meeting of IUFRO Working Party 7.02.09: Phytophthora in Forests and Natural Ecosystems; Vietnam

3/28 – 3/30 – 63rd Annual Conference on Soilborne Plant Pathogens (formerly Soil Fungus Conference) and the 49th Annual California Nematology Workgroup; University of California, Davis

See the entire events calendar.