Pest Control

Projects We're Working On: GSOB Confirmed in the Hodges Watershed

GSOB has now been found in Del Dios Park, on Laurel, Kalmia, and Juniper Lanes. It is also on Mount Israel near Detwieler Road. We can assume in the next several years our large Coast Live Oak trees will see GSOB. The adult beetles emerge from mid-May through August, so presence of the beetle in healthy trees may not be detectable yet.

Residents and the City of San Diego are being urged by the Del Dios Habitat Protection League to protect high value oaks from this deadly invasive beetle. We are putting together a community plan to treat trees together to reduce the individual tree cost.

We are asking for people who are interested in being part of the solution to step up and contact Stacy McCline right away.

The gold spotted oak borer is a tiny beetle causing huge damage in Southern California. It infests the region's towering oak species - coast live oak and canyon live oak - and can kill a centuries-old tree in just a year or two.

GSOB Update: May 2017

GSOB Confirmed in Del Dios and Mt. Israel

This beetle - the Gold Spotted Oak Borer, is a highly invasive, non-native flathead borer that kills oak trees.

San Diego County Ag has confirmed the presence of GSOB based on pictures submitted to them on Thursday May 11, 2017. So far, Clark Mahrdt and I have identified the oak killing beetle in two locations on the north end of Del Dios, as well the confirmed location on Mt Israel near Detwieler Road. Additionally, Conor Lenehan, RSF Fire, announced its presence on Mt. Israel at the Elfin Forest/Harmony Grove Town Council meeting last month. According to neighbors, GSOB may have arrived in Mt. Israel a few years ago, but we believe this to be a new problem in Del Dios, based on my examination the trunks of failing and dead oak trees for the last 3 years.

Please review the GSOB Identification Guide, especially page 5. When you first start looking at the trunk of a mature oak tree you will notice there are a lot of different shapes and sizes of holes in it. GSOB has a characteristic D-shaped hole in the bark, about the size of the lead of a #2 pencil. 

GSOB D Shaped Hole in Oak Zoom.jpg

Evidence of GSOB

GSOB has a characteristic D-shaped hole in the bark, about the size of the lead of a #2 pencil.

The first steps for limiting the spread of this infestation are 1: Alert the community that no oak wood should be moved in or out of our area and 2: Determine the extent of the problem – how many trees are effected and how they are grouped. According to the resources below, activities to contain the extent of the damage by GSOB include removing dead and dying trees effected with the beetle and using preventative treatment of unaffected or slightly affected trees in the vicinity.

We will need to work together and coordinate our efforts to be effective in stopping the spread of this pest in our area.

I will post again as I have more information to share.

Stacy McCline


Del Dios Habitat Protection League



Additional links, resources and video can be found in our original GSOB post.

Why you shouldn't move oak firewood

The Goldspotted Oak Borer (GSOB) is tiny beetle that’s infesting and killing oak trees in San Diego County. This beetle came from Arizona, where the environments have predators that naturally keep the beetle populations under control. Here in California, the only method of controlling the spread of GSOB is containment.

Cut wood that’s infested is still a threat, so don't move firewood, and follow some basic containment techniques to keep any mature beetles from escaping and reproducing.



University of California - Learn more about containment strategies, report GSOB sighting, download GSOB Field Identification Guide

University of California Agriculture & Natural Resources - Integrated Pest Management Program

San Diego Union Tribune - Beetles take a bite out of backcountry (Feb. 17, 2013), Oak deaths top 80,000 in San Diego County (Sept. 2, 2011)

California Firewood Task Force - Learn about the "Buy it Where You Burn It" campaign

Firewood Scout - Need to buy firewood? Find a vendor that knows where their supply comes from and has taken necessary precautions by seasoning the wood for two years or heat treating it.

California resources & info on Don't Move Firewood dot org