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Sudden Oak Death

UCCE Mendocino participates in collaborative research and outreach & education programs with neighboring UCCE counties to provide information about the plant disease, sudden oak death.

What is Sudden Oak Death (SOD)?

Pythophthora ramorum, the cuase of Sudden Oak Death
Pythophthora ramorum, the cuase of Sudden Oak Death

Sudden oak death (SOD) is caused canker-causing pathogen called  Phytophthora ramorum, which is a microscopic fungus-like organism. The pathogen is lethal in some true oaks (Quercus) species and tanoak, but it also Ramorum leaf blight, a non-lethal leaf blight that can cause stem cankers, leaf spotting, and twig dieback in a large number of native and ornamental trees, shrubs, and herbaceous plants in the Pacific Northwest and Europe.

Sudden Oak Death quarantine map.
Sudden Oak Death quarantine map.
Sudden oak death was first recognized in North America in the mid 1990's. In July 2007, it was first detected in southern Lake County and in June 2008 it was detected in Mendocino County. To date, SOD can be found along the north coast from Monterrey County to southern Oregon.

The movement of host materials (leaves, firewood, logs, etc.) within and out of these counties is regulated by State and Federal quarantines to prevent and/or slow further spread of this disease.

For more comprehensive information on sudden oak death visit suddenoakdeath.org

Additional information can also be found on the UCCE Humboldt-Del Norte Sudden Oak Death website.

Citizen Science Programs

SOD Blitz Project

SOD Blitz is a citizen science driven project that aims to inform and educate the community about Sudden Oak Death, get locals involved in detecting the disease, and produce detailed local maps of disease distribution. The map can then be used to identify those areas where the infestation may be mild enough to justify proactive management.

To learn more about Sod Blitz or to get involved please visit:



The Mendocino County Blitz will be Saturday, June 6th:

10-11:30 am: Historical Farmhouse at the Mendocino Coast Botanical Gardens, 18220 North Highway 1, Fort Bragg, CA 95437

Contacts: Mario Abreu abreu@mcn.org

Please note the workshop format has been modified to conform to COVID-19 restrictions. More information can be found on the sobblitz.org website

Sonoma County Blitz

For information on SOD in Sonoma County, check out the UCCE Sonoma SOD web page.


SODMap Project

SODMAP is the result of a collaboration between hundreds of citizen scientists participating each year in the SOD Blitzes organized by the U.C. Berkeley Forest Pathology and Mycology Laboratory, other research organizations, and government facilities.

To learn more about the project and download the newest SODMap, please visit:



OakSTeP Project

Oak SOD Testing Program is a new program launched by the U.C. Berkeley Forest Pathology Laboratory to facilitates the cooperation between professional tree care specialists, oak owners who are their clients, and U.C. scientists to provide a rapid and inexpensive diagnostic service on SOD infection on oaks.

For more information about OakSTeP, please visit: