About Sudden Oak Death

What is Sudden Oak Death?

Sudden Oak Death is a devastating forest disease that kills oaks, tanoaks and several species of endangered manzanitas. The pathogen also infects the leaves of important nursery and garden plants, and those used in indigenous cultural practices. Sonoma County has experienced more infection than any other in California since discovered here in 2001, and has the only UCCE sponsored research and outreach program.

Two native trees California bay laurel (Umbellularia californica) and tanoak (Notholithocarpus densiflorus) act as "foliar hosts," carrying the pathogen on their leaves then spreading it to trunks and branches of "canker hosts" like native oaks and tanoaks. Finding out which individual foliar host trees are infected via the SOD Blitz allows land owners and managers to take action to prevent infection on canker hosts like our majestic Coast Live Oak (Quercus agrifolia) which is very susceptible to infection and death. Foliar infection is important to catch early, because once a canker host has become infected, there are no known effective treatments.

Stay up to date on the most recent SOD news by reading the current California Oak Mortality Task Force newsletter and browse their comprehensive website about SOD

Sudden Oak Death and Phytophthora ramorum: A Summary of the Literature. John T. Kliejunas, USDA Forest Service, 2010

Which plants are susceptible?

Before you take action, check to see if your oak is susceptible to SOD. Here's our handy guide for which species are susceptible in Sonoma county: Oaks in Sonoma County ID

It's important to know which plants can spread SOD to your oaks, tanoaks, and manzanitas. Reference the updated APHIS List1 of Regulated Hosts and Plants Proven or Associated with Phytophthora ramorum

Manzanitas are also at risk of infection. See a list of species here

What can be done about it?

Reference Manual for Managing Sudden Oak Death in California. What we know and don't know about SOD management in California

Homeowner's guide to Sudden Oak Death

Sudden Oak Death Management Guidelines Latest guidelines from University of California

Protecting Trees from Sudden Oak Death before Infection

SOD Treatment Information

SOD Blitz-Monitoring our neighborhoods and forests for SOD

Still have questions?

Submit your questions about SOD to TreeFAQs on UC Berkeley's sodblitz.org website that also houses SOD information, research, and event listing

Sudden Oak Death Education Program reports