Cathy Roache
County Agricultural Commissioner / Sealer
Agriculture / Weights & Measures

Pest Exclusion

Sudden Oak Death (SOD) Program

Photo of a oak trees killed by Sudden Oak Death Syndrome.
Coast Live Oaks killed
by Sudden Oak Death
Enlarge Photo
Photo of spotting on bay leaves caused by  Sudden Oak Death.
Spotting on bay leaves
caused by Sudden Oak Death
Enlarge Photo
Photo of bark bleeding on coast live Oak tree.
Bark bleeding on Coast Live Oak
caused by Sudden Oak Death
Enlarge Photo
Photo of Sudden Oak Death-infected tissue from Coast Live Oak.
Sampling Sudden Oak Death-infected
tissue from Coast Live Oak
Enlarge Photo

Alameda County is one of fourteen regulated counties in California where SOD is known to occur. This plant disease is caused by the pathogen Phytophthora ramorum, a fungus-like organism that thrives in the moist climate found along coastal California. Although a number of native and ornamental species are known hosts for this disease, Coast Live Oaks, Tan Oaks and Black Oaks can actually be killed by it.

Alameda County currently has infested sites in Redwood Regional Park, East Bay Municipal Water District property and one hillside in Castro Valley. All of these sites are in wildland areas, characterized by Oak/Bay woodland. Our program involves ongoing survey work to detect any additional SOD infestations in the county. We also examine trees suspected of being infested with SOD, and collect tissue samples for lab analysis when warranted by the observed symptoms.

State and Federal regulations have been created to help slow the spread of this disease by controlling the movement of SOD host material. This includes plants and plant products such as nursery stock, Christmas trees and wreaths, fire wood, bark chips, burls and other unprocessed products from host plants. A summary of the regulations can be obtained by contacting our office at (510) 670-5232.

We also inspect our production/wholesale nurseries annually to ensure freedom from SOD. In addition, shipments of host nursery stock are inspected prior to leaving the 14 regulated counties.

Outreach and education programs have been created to provide information to both homeowners and people in industries using SOD host materials. A new brochure entitled Sudden Oak Death in Alameda County has been created to help people understand this problem and how it affects them. Select the link below to open the brochure.

If you are concerned about your oak tree or would like more information on this disease and how current regulations may affect you or your business, contact our office for more information at the number listed above.


The following documents are provided in Portable Document Format (PDF) and require the free Adobe Reader.