SOD-Oak-bleedingAn Oak with SOD caused bleedingSOD-sporangiaSOD sporangia

SOD Blitzes reach the eleven-year mark.
Volunteer to help in the fight against Sudden Oak Death deemed extremely crucial in 2017

Sudden oak death (SOD) is a serious invasive disease that is killing tanoak, coast live oak, California black oak, Shreve’s oak, and canyon live oak trees in California. It is the primary cause of tree mortality in coastal California, with more than 5 million trees having died in since its discovery in the mid-1990s. A water-loving organism, the pathogen continues to spread in drought years, but at a much slower rate than in wet years.
This year is poised to be one of the most significant in a decade for SOD. Given the well above normal precipitation and two consecutive wet years in California, researchers hope to recruit as many citizen scientists as possible for the 2017 SOD Blitz surveys. Extensively monitoring at-risk communities for spread of the pathogen that causes SOD (Phytophthora ramorum) will be vital to optimizing oak protection.

“It is essential that we have as many eyes in the field as possible looking for SOD symptoms this spring. With all of the wet weather, it is likely that Phytophthora ramorum is on the move. Super-sized SOD Blitz surveys will more thoroughly inform communities about local pathogen activity, empowering them to make educated decisions
about where best to focus preventative treatments and manage for the pathogen to help protect susceptible oaks. Prevention is key,” said Matteo Garbelotto, the UC Berkeley faculty member who runs the Blitzes.

People living or recreating near areas known to be impacted by SOD are encouraged to participate in a Blitz. Volunteers with a smartphone should bring it to the training with the free SODMAP Mobile app already installed, as it can help in identifying potential collection locations. Bring a GPS unit if a mobile device is unavailable.
Symptomatic California bay laurel and tanoak leaves generally precede oak infections, and are often the first sign that P. ramorum is in a location. Participants will be trained to identify and collect symptomatic bay and tanoak leaves as well as tanoak twigs and record sample locations. All materials necessary for sampling will be provided during training sessions.
SOD Blitz samples will be taken to the UC Berkeley Garbelotto lab to determine the presence or absence of the pathogen. Results will be posted online in the fall to SODMAP and to the SODMAP Mobile app. These two tools are updated annually with laboratory-confirmed (positive and negative) landscape findings and can be used to help inform people as to the presence and risk of SOD at a given location.
SOD Blitzes are made possible by the work of local volunteers, along with funding from the PG&E Foundation and the State and Private Forestry organization of the USDA Forest Service.
For more information on Sudden Oak Death and P. ramorum, visit the California Oak Mortality Task Force website or contact Katie Harrell at 510.847.5482 or For more information on the Blitzes, visit

Marin meeting location:
Joseph R. Fink Science Center, Rm 103, Dominican University, San Rafael (1 hour presentation).
Next meeting, May 6, 2017, starting at 1:00 PM

For more information, write Wolfgang Schweigkofler