We’ve heard several recent news reports about “sudden oak death,” a tree disease moving along the N. California Coast and currently affecting all counties from Sonoma south to Monterey. Concerned about the live oaks on our upper hillside, and also planning new landscaping in front of our home, I did some online research… and the results are alarming. This is a big deal.
The disease affects and kills virtually all native coastal oak species. It’s spreading rapidly and may destroy virtually the entire native oak forests, including parklands in Marin and Big Sur as well as oaks in our own “urban border” landscaping.
A California Oak Mortality Task Force has been formed and offers considerable information on the disease, symptoms and treatment. I’m including a link to this information below. Here are a few key facts:
- The pathogen that causes Sudden Oak Death is Phytophthora ramorum, a water fungus which spreads via spores carried by rainwater and can also be spread by passing animals and people, firewood and cleared brush.
- The fungus spores spread onto oaks in splashing raindrops from many types of nearby trees and shrubs which are not affected (as yet) but serve as hosts and transmitters.
- The Phytophthora ramorum fungus is identical to the disease affecting European rhododendrons - in Europe, P. ramorum has been identified on nursery plants in Germany, Spain, France, Poland, Belgium, Sweden, Italy, the Netherlands, and the U.K.
- The first visible symptom of Sudden Death Oak infection is a seeping red-brown liquid on the tree trunk – but certain diagnosis requires a trained arborist and a state laboratory test.
- There is currently no cure – but an effective preventative treatment, Agri-Fos, was approved by the California Department of Pesticide Regulation in October 2003. It must be used prior to infection to be fully effective.
Here is URL of the very informative California Oak Mortality Task Force site – including a list of arborists who have been formally trained in the disease diagnosis and Agri-Fos treatment: http://www.suddenoakdeath.org/
Hopefully, this will get us started on protecting our own oaks… and the beautiful wooded character of our community.