Beetle claims more oak trees in Ramona
By Karen Brainard
The goldspotted oak borer (GSOB) continues to claim the lives of oak trees in Ramona.
Latest casualties include two oak trees on the San Vicente Golf Course and a tree in the right-of-way on Archie Moore Road, south of Rancho De la Angel Road.
Ramona Community Planning Group voted Sept. 4 to recommend to the county that the tree on Archie Moore be cut down as it is now considered a safety hazard.
“Ramona is on the cutting edge of infestation,” said Dr. Tracy Ellis, an entomologist with San Diego County Department of Agriculture, Weights and Measurements.
Dos Picos Park is one area that has lost trees, she said.
“All along Mussey Grade Road has really been hard hit,” said Ellis.
San Vicente Golf Course has lost six to eight oak trees in the past year due to the deadly beetle.
“These are stately old oak trees,” said Pat Shannon, golf course superintendent for the past 23 years.
According to Ellis, San Diego County was the first county in the state to be infested with the GSOB.
The beetle has its own dedicated website, GSOB.org, through the University of California Cooperative Extension.
According to the website, GSOB was first collected and identified in California in 2004 in San Diego County but was not linked to extensive oak mortality until 2008.
Ellis said it is believed the beetle was transported from Arizona to San Diego through infested firewood. She emphasized the importance of not moving firewood.
She also noted that there is no known mechanism to stop the beetle from spreading and killing trees.
“It’s not a pest that we can regulate because it’s already widespread,” she said.
Three oaks are known to be affected by the GSOB: coast live oaks, canyon live oaks and California black oaks. Ellis said the beetle does not appear to be detrimental to Englemann oaks.
Researchers and arborists are working on management practices to prevent trees from falling prey to the beetle.
When a tree is infested with GSOB, it dies quickly, said Shannon.
“Once this takes hold, trees are gone in a couple of weeks,” he said.
He pointed out the 4.5-foot diameter stump of a 200-year-old oak tree in the rough of Hole No. 9 that fell victim, and an oak behind the ladies’ tee on Hole No. 8 that began turning brown three weeks ago.
“You can actually tell when a tree is infected, it leaves a letter “D” shaped hole,” explained Shannon, noting that the holes are tiny.
A process must be followed once a tree is cut down to prevent further spreading of the beetle.
“Do not remove oak firewood from local infested areas to prevent the potential spread of GSOB in new areas,” states the University of California website.
At the golf course, the oak trees have been cut up and stored under sheets of black plastic behind a practice area. Shannon said they will remain there for a year and the heat under the plastic will cause the beetle to die. After a year, the wood can be split and used for firewood, he said, adding that he is following recommended practices.
In addition to the “D” shaped hole, other symptoms of the GSOB infestation of a tree are red or black staining in dime-sized to half-foot sections, blistering and oozing on the surface of the tree, crown thinning, twig and branch die-back, and premature leaf loss.
Ellis recommended that those who suspect they have a tree infested with GSOB fill out a form on the GSOB.org website to report it and for possible inspection. Doing so helps the county and other agencies determine distribution and impacts of the beetle, states the website.