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Sudden Oak Death disease threatens survival of oak species in SLO County

Sudden Oak Death disease is found on this tree. The disease has been confirmed in San Luis Obispo County for the first time.
Sudden Oak Death disease is found on this tree. The disease has been confirmed in San Luis Obispo County for the first time.

Q: Do we have Sudden Oak Death in San Luis Obispo County?

Bob G., Paso Robles

A: Yes, tests have confirmed the presence of Sudden Oak Death for the first time in San Luis Obispo County.

This is a serious exotic disease that is threatening the survival of tanoak and several oak species in California, including coast live oak. Sudden Oak Death is now found in 16 coastal counties, from San Luis Obispo to Humboldt County. The disease spreads from infected California bay laurel leaves to oaks.

Management options are available, but they are only effective if implemented before oaks and tanoaks are infected, so timely detection of the disease on bay laurel is essential.

Hosts, such as California bay laurel, suffer less damage and do not die from the pathogen. Despite this, the bay laurel is significant because it can harbor and spread the disease.

Diagnosing the disease is tricky. A laboratory test using either culture techniques or DNA analysis is necessary to confirm the presence of Phytophthora ramorum. Once the pathogen’s presence is confirmed, proper disposal of leaves, twigs and branches is an important step toward limiting the spread of the disease. Removal of the tree or infected plants may be necessary.

The community can help by volunteering to sample suspected bay laurel leaves at this year’s SOD Blitz. The purpose of the SOD blitz is to educate the community about the disease and its impact, involve local residents in detecting the disease, and produce detailed local maps of disease distribution.

The training is free and all necessary materials will be provided. The blitz consists of one training session and collecting leaves from suspect bay laurel trees.

This year’s SOD Blitz training sessions are planned at two locations:

▪  Thursday, May 11, 1 to 4 p.m., San Luis Obispo County Department of Agriculture, 2156 Sierra Way, San Luis Obispo.

▪  Friday, May 12, 6 to 8 p.m., Atascadero Library, Martin Polin Community Room, 6555 Capistrano Ave., Atascadero.

Collections will take place on May 13 and 14.

Register for the SOD Blitz training at http://ucanr.edu/sites/mgslo.

Andrea Peck is a UCCE Master Gardener.

Got a gardening question?

In San Luis Obispo call 805-781-5939, Arroyo Grande, 805-473-7190 and Templeton, 805-434-4105. Visit us at http://ucanr.org/sites/mgslo/ or email us at anrmgslo@ucanr.edu. Follow us on Instagram at slo_mgs and like us on Facebook. Informative garden workshops are held the third Saturday of every month, 10 a.m. to noon at 2156 Sierra Way in San Luis Obispo. Garden docents are available after the workshop until 1 p.m. To request a tour of the garden, call 805-781-5939.