Sudden Oak Death in Sonoma County

Results are in from a county-wide sudden oak death (SOD) survey. Dr. Garbelotto, UC Berkeley Forest Pathologist, will present the results and talk about their significance in Sonoma County. This survey, called a SOD Blitz, was organized by the UC Master Gardeners and was carried out by 70 Sonoma County volunteers in mid-April of this year. California bay laurel leaves, symptomatic for SOD, were collected from California bay trees in several areas of the county and sent to the Berkeley Forest Pathology lab for diagnosis.

Saturday, June 19th, 2010 

11:00 a.m. - Noon 

UC Cooperative Extension

133 Aviation Blvd., Suite 109

Background
Sudden Oak Death (SOD), a serious exotic disease, is threatening the survival of tanoak and several oak species in California. Currently SOD is found in the wildlands of 14 coastal California counties, from Monterey to Humboldt. While patchy in distribution, with each passing year, the swath of infection continues to become more contiguous. Researchers have discovered that Phytophthora ramorum, the pathogen that causes SOD, spreads most often on infected California bay laurel leaves. Symptomatic bay leaves are often the first sign that SOD has arrived at a location, and generally precedes oak infections. Some management options are available (sanitation, chemical preventative treatments, bay removal), but they are effective only if implemented before oaks and tanoaks are infected; hence, timely detection of the disease on bay laurel leaves is key for a successful proactive attempt to slow down the SOD epidemic.

“Our greatest defense against this aggressive invasive plant disease is to take proactive measures. By doing so, we can optimize our chances of containing it where it is found and protecting those areas that have not yet been exposed to it. Without a cure, treatment and prevention strategies are our best defense,” said Mark Stanley, chairman of the California Oak Mortality Task Force.

Caused by the plant pathogen Phytophthora ramorum, Sudden Oak Death is severely impacting woodlands throughout central California. Since the 1990s, P. ramorum has killed more than a million oak and tanoak trees in California.

For more information on Sudden Oak Death and P. ramorum, contact the UC Master Gardener Desk at (707) 565-2608.

Lisa Bell
Agricultural Program Assistant
Sonoma County UC Cooperative Extension
133 Aviation Blvd., Suite 109
Santa Rosa, CA 95403
(707) 565-2050
lkbell@ucdavis.edu