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Sudden Oak Death 2012 blitz results

Sudden Oak Death 2012 blitz results


On May 12, a group of volunteers met in Napa with Doug Schmidt of the UC Berkeley Forest Pathology and Mycology Laboratory to begin Napa’s 2012 Sudden Oak Death Blitz, an ongoing effort to map Sudden Oak Death disease and inform the public on the status of this devastating disease. It was one of 20 such events held this spring at locations ranging from Carmel to Sonoma and Napa counties. The results were released to the public on Thursday.

In the Napa Blitz, 56 samples yielded 19 positives for the Sudden Oak Death organism, Phytophthora ramorum. Overall, for the entire Sudden Oak Death Blitz effort this year, 2,087 samples generated 639 positives.  

As the local volunteer coordinator for Napa’s part in the Blitz, I am providing a brief summary of highlights from lab director Matteo Garbelotto’s report. (I’ve pared it down and paraphrased for the space available.)

“1. The U.S. Forest Service, using flyovers, noticed a significant spike in tree mortality. We forecast this when we published the 2011 results. The Blitzes are now confirmed as an excellent early warning. This is extremely important because early treatment greatly increases the chances of survival.

2. In Golden Gate Park, three trees tested positive near Middle Lake. This is the second time an outbreak is detected in the park and researchers and park managers suspect the infection may be linked to latent infections present in rhododendrons. City officials are pleased the infestation was detected at an early stage and are working with researchers to decide how to curtail it.

3. Burlingame Hills has a widespread infestation. Some residents have already started a prevention program. We hope more residents will participate now that the results are out. The infestation is widespread, at high levels and diffuse in the entire area. Sausalito has a significant infestation as well. The outbreak is really moving into the residential neighborhoods in the southern part of that town.  

4. East Bay, oh my: Last year, we reported Sudden Oak Death had arrived in residential neighborhoods of the East Bay. The results indicate infection levels are now high and oaks are at risk in East Richmond, Kensington, North Berkeley, Claremont, Montclair and Piedmont. This applies to private properties and any camps, open spaces and parks. I am hoping those who manage these open spaces will be reading the results.

5. East Bay (2); Infection is confirmed in Pinole and especially in Orinda-Moraga, and it is approaching Lafayette. No positives for Mount Diablo, but we need to better sample the area.

6. In our first Santa Cruz Blitz, we have found P. ramorum basically almost in the town of Santa Cruz itself, and all along Highway 9, clearly showing how the Saratoga Mountains infestation is linked to the original outbreak near Scott's Valley.

7. Good news showing how early detection helps. The single outbreak we had previously detected in Atherton has been temporarily eradicated, and now we need to keep monitoring to make sure it stays out.

8. In Woodside-Portola Valley and Los Altos Hills, Sonoma, Napa and Carmel Valley, we noticed the pathogen is persistent and expanding in slightly drier areas and in urban areas so it is important to keep the outreach going. In particular, it is now well established east of Interstate 280 in the peninsula and at the Napa-Solano border.

Our effort does not stop with the Blitzes. Thanks to funding from the U.S. Forest Service, State and Private Forestry and the Gordon and Betty Moore Foundation, we have scheduled many town hall meetings. The list of all meetings (about 20) organized throughout and beyond the Bay Area can be found at

In these meetings, we discuss results, explain how to use the maps to determine the risk of infection, and teach how to protect trees.”

To review the 2012 Sudden Oak Death Blitz results, visit: or just Google: matteolab.

Napa’s Sudden Oak Death Blitz “town hall” meeting is scheduled for Friday, Nov. 9, 7 p.m., at the UCCE meeting room, 1710 Soscol Ave. The meeting is free and open to the public. An outdoor session will be on Sunday, Nov. 18, 1 p.m., at a location to be announced.

Bill Pramuk is a registered consulting arborist. Visit his website,, email questions to, call him at 226-2884 or visit Bill Pramuk Consulting Arborist on Facebook.

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