Sudden Oak Death appears in San Francisco's Presidio

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A coast live oak tree on the southeastern edge of the Presidio National Park in San Francisco was found to have Sudden Oak Death disease, according to an article in the San Francisco Chronicle.

The disease was believed to have made its way to the tree from an ornamental plant at a nearby home, reported Matteo Garbelotto of UC Berkeley's Forest Pathology and Mycology Laboratory. Scientists are concerned about the find because it means the microbe escaped from an ornamental and infected a wild tree despite an intensive nationwide effort to control the disease in nurseries.

“I was surprised by the finding because the Presidio is located in an urban setting, far from any other known infestation,” Garbelotto was quoted in a news release from the California Oak Mortality Task Force. “With a few exceptions, all known infestations are close to oak woodlands or redwood forests.”

The infected oak is one of the few native trees in the Presidio, wrote Chronicle reporter Peter Fimrite. Of the 60,000 trees in 300-acre park, only about 200 are native oaks.

The infected tree was discovered by an arborist for the Presidio Trust. The Garbelotto lab took samples, which showed a strain of sudden oak death that is normally seen only in ornamental plants. Laboratory workers tested other trees, plants and soil samples from the same area, but no evidence of the pathogen was found.

Garbeletto told the reporter the find should serve as a wake-up call across the United States.

"People's ears should go up in states where they have it in nurseries but not in the wild," he was quoted. "It shows that it can escape."

The Presidio Trust will be conducting a "SOD Blitz" April 29 to May 2, when hundreds of samples will be taken throughout the Presidio and vicinity. Training for the cooperative effort to sample for the pathogen will be provided by Garbelotto on Friday, April 29. Residents near the Presidio have been invited to participate in the training as well as follow-up sampling efforts on their properties. For more information, see http://www.suddenoakdeath.org.

Camellia leaf infected with the pathogen that causes Sudden Oak Death.