With the arrival of spring and expectations of locating goldspotted oak borers, only one more affected tree has been identified, according to Riverside County’s Forester Chief Gregg Bratcher.
Last month, the county Agricultural Commissioner’s Office held a meeting with potential contractors who could spray trees, Bratcher said. The intent was to increase their awareness of the pest’s presence in the county and on the Hill, and the potential for residents to use their services.
More information about the possibility and disclaimers of this choice, including a list of licensed pest control operators in Riverside County who attended the GSOB informational meeting, are at
http://ucanr.edu/sites/gsobinfo/Resources/By_County/Riverside_County/Licensed_Pest_Control_Operators-Riverside_County/
Although only one more tree has been identified, Bratcher believes the recent heat wave will expand the GSOB’s range. A trap at the Grinding Station has recently seen the emergence of hundreds of beetles.
According to Kevin Turner, goldspotted oak borer program coordinator at the University of California, Riverside, traps around material ground to recommended specifications indicate few larvae survive, but bark less finely ground is the source of emerging beetles.
The Mountain Communities Fire Safe Council is continuing its inspections of trees, said Executive Director Edwina Scott.
It also has placed traps around town and in Pine Cove. The large purple triangular objects hanging from trees will help determine how active and widespread the potential infestation is.
Scott also announced that the MCFSC abatement contract, scheduled to terminate June 30, has been extended through Sept. 30. So funds are still available to help property owners complete fire abatement. Call (951) 659-6208.
Caltrans closed Highway 243 in front of Mountain Top Liquor on Thursday, April 11 from around 9 a.m. until 1 p.m. to remove a large Goldspotted oak borer-infested tree. Photo by Marshall Smith
Beginning around 9 a.m. Thursday, April 11, Caltrans crews closed Highway 243 in front of Mountain Top Liquor to take down a five-story tall Goldspotted oak borer-infested tree. After removing the first tree, crews moved on to a second infested tree near the Chevron station. Caltrans reopened Highway 243 at 12:42 p.m. according to Caltrans Highway Maintenance Supervisor Jody Mueller. Removal of the second tree did not necessitate keeping the highway closed. The operation wrapped around 2 p.m.
These two trees were the second and third in Idyllwild to be confirmed as infested with Goldspotted oak borer. Since then, other trees were confirmed as having the insect and either taken down or scheduled for removal, including one at Town Hall and one across from the American Legion Post 800 on Marion View Drive.
Larvae from a suspected infested tree in Pine Cove have been sent out for DNA analysis and results should be available in several weeks, according to Gregg Bratcher of CAL FIRE.
Confirmed Goldspotted oak borer-diseased trees are taken to the grinding station, sectioned (“canted”) and ground down to destroy any existing larvae, according to Kevin Turner, U.C. Riverside GSOB project coordinator. Contrary to some reports, infested trees are not debarked and used for firewood stored at the grinding station as part of official Idyllwild area removal procedures. Turner explained the economics of debarking trees make the process impractical. “If debarking trees were easy and cost-effective to accomplish, it would be occurring in San Diego County [locus of high Goldspotted oak borer infection and tree mortality], which it is not.”
Garden Club sign warning about oak transportation.
The Idyllwild Garden Club takes a major step in trying to stop further Goldspotted oak borer infestation in Idyllwild. It has commissioned and will install roadside signs advising against importation of oak onto the Hill.
“Our budget allowed for 10 signs,” said Mike Feyder, Garden Club instigator of the sign project. At present the club plans to install signs at the intersection of Highway 371 and Highway 74 in Garner Valley, three more between Garner Valley and Mountain Center, several on Highway 74 coming from Hemet to Mountain Center, one in Mountain Center at the beginning of Highway 243, one coming into Idyllwild and one each at the county and state park entrances.
Feyder said the sign will be 3 feet by 4 feet of durable corrugated plastic mounted three to 4 feet above the ground on posts. Signs are being produced and should be ready next week, said Feyder. “All this effort is going to do is announce that we have a problem and to increase awareness of the risks of firewood transportation.”
GSOB volunteers gather around an infected tree during Tuesday’s training. Photo by Marshall Smith
Four more Goldspotted oak borer-infested trees have been identified in Idyllwild. When authorities identified the first infested tree here in November, they expressed hope that it was an isolated incident. Authorities no longer believe the outbreak is limited.
Since tree one was on Highway 243, it appears to have been almost certainly infested from firewood transported from San Diego County and perhaps the imported firewood location was near the infested tree.
Trees two and three were identified on Jan. 19, one near Mountain Top Liquor and one at Town Hall. Last week, authorities identified four more infested trees, Three are along Highway 243 between tree one and tree two. The seventh tree, which CAL FIRE Forester Gregg Bratcher called a monster oak, 147 inches in diameter, is on private property on Marian View Drive, and was identified by an Edison employee.
At this point, although Dr. Tom Coleman, U.S. Forest Service entomologist and lead Goldspotted oak borer scientist, has begun to talk about insecticides, both topical and systemic. Those candidate insecticides have never been used in the field against California Goldspotted oak borer. If used, application costs would not be small, and results could be short-lived, long-lasting or ineffective, depending on success of application mathods. Another potential control agent, importing a Goldspotted oak borer predator from Arizona where this particular oak borer is native, waits years of scientific trial and investigation to ensure the importation would be effective and have no unintended consequences.
At present, the surest way to stop the insect’s spread is to remove and grind the tree, tarp the firewood (using window screen that won’t deteriorate with the elements), or debark the firewood and arrange to have the bark taken to the grinding station.
Removal stops spread, but removal is also expensive, depending on the size of the tree, location near a home. camp or park. And should the Idyllwild outbreak grow to the extent of the catastrophic bark beetle crisis in the early part of the last decade, the issue becomes for public and private landowners, who would bear costs of removal?
Bratcher said he is working on obtaining county grants that could assist private landowners, much like the Forest Care program has helped thin parcels. He also mentioned that Southern California Edison, much as it did during the bark beetle emergency, could remove infested trees that threaten its power lines, although that has not yet been agreed with SCE.
CAL FIRE, University of California, Riverside, and the Forest Service are conducting field exercises to train professional responders, public agencies, volunteer groups and private citizens on how to spot Goldspotted oak borer infestation in Hill oaks.
On Tuesday Feb. 5, Bratcher, UCR GSOB Program Coordinator Kevin Turner, and Dr. Tom Scott, UCR GSOB scientist conducted a field training for about 30 members of the Mountain Communities Fire Safe Council’s Woodies, the Idyllwild Garden Club, and some CAL FIRE personnel in a two-hour spotting exercise. By spring, CAL FIRE wants as many citizen-scientists on the ground in the Idyllwild area as possible to assist in GSOB tree identification. Spring is when a larger outbreak is likely to occur.
If anyone has a tree that they feel looks as if it could be infested, call the new GSOB Hot Line at the Resource Center on Franklin Drive. That number is (951) 659-8328. Bratcher stressed that all potential oak borer calls must come to the Resource Center number, so that they are logged in. “We need to have a protocol and stick to it,” he said. “Go through the mechanism, the GSOB line.”
Volunteers for citizen scientist GSOB training, to act and report as civilian spotters, should call the Mountain Communities Fire Safe Council at (659) 659-6208. CAL FIRE has smartphone apps that could be used by field personnel to identify the oak borer infestation.
Many in the Tuesday training discovered how hard it is to identify the “D” shaped GSOB exit holes in Hill black oak. Scott explained that the trees most affected in San Diego County are not black oak, and the exit holes are larger and easier to spot. In black oak, with darker bark striations, the smaller holes are harder to see.
There is a current and real threat to most of the oaks in our community — the GSOB or the Goldspotted oak borer.
This beetle has killed tens of thousands of oaks in San Diego County, and has now been positively identified in Idyllwild. So far it has been found in three trees around the center of town and possibly a fourth.
Whether or not we can contain it will depend on how well we as a community, residents and agencies together, act to identify and remove infested trees.
The GSOB is not native to California, so it presents all the problems of an invasive pest — no natural predators, and limited host immunity.
It is native to southeast Arizona and points further south, and was mostly likely brought to San Diego in the 1990s in the form of firewood, which is almost certainly how it traveled here.
The mature beetle lays eggs on the bark surface and in crevices. After the eggs hatch into larval form, the larvae bore into the tree and grow underneath the bark, feeding on the tree and damaging its water and nutrient systems.
When the bug matures into a beetle, it exits the tree to find another host, leaving a small D-shaped exit hole when it emerges. Red staining is clearly evident under the bark, and sometimes on the external bark.
Unfortunately, we have no treatment as yet for an infected tree. Dr. Tom Coleman of the U.S. Forest Service, the foremost authority, is now conducting research on the effects of various insecticides, but the research is only in its middle stages and he cannot recommend any chemical to kill the beetle when it is identified in a live tree.
Like many public health threats, we must focus on prevention. No one should buy any oak that they are not certain is free of the GSOB. This means no oak from off the Hill, and no local oak unless someone knowledgeable assures you it is free of the beetle.
Burning infected wood will kill it, of course, but letting it lay outside in the warm months will allow it to mature and spread to oaks around your house.
The other public health action we must take is surveillance. There are certainly other infested oaks around town, and the sooner we can find them the sooner the tree can be removed, thus limiting the spread.
Everyone with oaks, especially black oaks, should pay close attention to their trees as spring approaches. The beetle likes large oaks, and will bore into the lower trunk, so anyone can check for staining or the D-shaped holes by looking at the lower part of the tree.
Our website, mcfsc.org, is loaded with lots of useful links for more information, or go to gsob.org or the Riverside County Fire website. Groups are working on this problem and more information should become available as they progress in their work.
Losing our oaks would drastically change the esthetics of the area. Many large black oaks are trees of great beauty and they are the most susceptible to the beetle. (It will also attack Canyon and Coast Live Oak.)
Please check your trees, especially as it warms, and if you suspect any are infected call the Nature Center at (951) 659-3850 to discuss your tree. Whatever you do, be extremely cautious about buying oak firewood, and avoid anything from off the Hill.
Oak tree die off in San Diego County. Photo courtesy of University of California Editor’s Note: Next week we will review firewood laws in other states as well as statewide quarantines in place in many states in the East and Midwest. Restrictive firewood laws and quarantines were enacted in response to invasive pests. In San Diego County, hard hit by the Goldspotted oak borer, no firewood laws or quarantines are in place at this time.
Some readers have discounted on our website the importance of the discovery of the Goldspotted oak borer in Idyllwild, noting that other pests or birds would take care of it and eliminate the problem. Those readers have not seen the devastation in San Diego County where more than $8 million in public and private funds have been spent or lost on oak borer mitigation activities, including dead tree removals and infested wood disposal.
Ninety thousand dead oaks, killed off since the Goldspotted oak borer was discovered in 2004 in San Diego County, is no small problem. And the reason it is a problem is that there are no natural predators for it in California. It is a non-native pest transported here in firewood from southeastern Arizona where there are natural predators that keep it in check. Were this insect to spread throughout California, mitigation costs would be enormous and property values would be greatly reduced. Oak tree death in San Diego. Photo courtesy of University of California
In San Diego County, much of the die-off has occurred on Forest Service land. Dr. Tom Coleman, Forest Service entomologist and Goldspotted oak borer expert, has spent the years since its identification studying the beetle’s patterns and investigating ways to combat it, either through topical applications, importation of a predator or other means to stop spread. Still, at this point in time, there are no existing effective treatments or approaches to stop die off.
Anabele Cornejo, assistant public affairs officer of the USDA Forest Service, Cleveland National Forest in San Diego, said, “At the California state level, a quarantine must be initiated by request from a county agricultural commissioner to the California Department of Food and Agriculture. To date, no county commissioners have made such a request, but rather they have expressed concern about a potential quarantine’s effectiveness, cost, logistical difficulties, and potential to draw away existing resources currently combating other invasive pest that threaten agricultural commodities.” D-shaped exit holes indicating infected tree. Photo courtesy of University of California
Cornejo said the extent of action to date in San Diego is the establishment of a committee to deal with eradication and containment issues. “In San Diego County, federal, state, county and city officials, working with the University of California, established a Goldspotted oak borer Steering Committee for a comprehensive cooperative approach to learning more about this invasive pest as well as how to confine, control and eradicate it.”
Cornejo also noted lack of funding is an impediment to erecting signs around infested Forest Service lands warning against transportation of firewood out of the infested zone. “Due to tight budgets, agencies cannot afford to rent billboard space,” she said.
Asked whether the Forest Service would continue to issue wood cutting permits in the GSOB zone of infestation, Cornejo said, “The Cleveland National Forest’s Descanso Ranger District has continued to issue wood permits to the public. Permitees are shown on a map specific areas where they can collect wood legally. The areas where trees have been down for two or more years and are not infested with GSOB. The inspection [of those areas] is done by either Dr. Tom Coleman or the Descanso District Lands Officer, Russ LaJoie.”
When asked what is being done with wood from infested trees (the oak borer can live in firewood for up to two years), Cornejo said, “Some trees are left where downed and used as habitat for area animals. Hazardous trees are downed and are allowed to sit for two years and then allowed to be used for firewood.”
A large crowd attends Dr. Tom Scott’s GSOB seminar. Photo by Marshall Smith
Since discovery of the invasive and dangerous Goldspotted oak borer in Idyllwild two weeks ago, scientists and professional responders from CAL FIRE and the Forest Service have been meeting to devise steps to contain the spread of the destructive beetle.
Kevin Turner, Goldspotted oak borer coordinator at the University of California, Riverside, said the next step is to work with the Forest Service to get an aerial survey of the Idyllwild area to map distribution of California black oak, the local oak Turner said is most susceptible to the beetle. “We’re hoping to identify and map black oak distribution on both public and private land in the Idyllwild area,” Turner said.
UCR’s GSOB scientist, Dr. Tom Scott. Photo by Marshall Smith“We’ve already done a ‘windshield survey’ of the Idyllwild area, checking trees to see if any have shown the same symptoms of early leaf shriveling and die off that characterized the infected tree recently removed on Highway 243.” Those involved included Turner, Forest Service lead entomologist Dr. Tom Coleman, CAL FIRE Division Chief Kathleen Edwards and UCR’s Dr. Tom Scott. “We did not find any that were similar,” said Turner. He also noted that there will be little movement of larvae during the winter months, and that symptoms of infection would not likely be seen until the arrival of warm weather next year. “We’ve surveyed areas around the infected tree, over where the Woodies cut wood (Idyllwild HELP Center), the County Park and South Circle,” Turner said. “I’ve been up there a lot and I saw nothing obvious that matched the same symptoms.”
Turner requested that private landowners with black oaks on their property report any symptoms that might be indicative of infestation. Again, those include early browning or shrinking of leaves, canopy thinning, and “D” shaped exit holes in the oak bark. Also, if people have firewood they suspect came from infected areas of San Diego County, they should call Turner’s office for someone to come out to inspect it. The number to call is (951) 827-2973.
If property owners suspect their trees are infected, Turner said someone from his working group would come out to check. “We can go back with the property owner’s permission, peel back the bark and look for [oak borer] larvae.”
Scott and Turner met with community members, including the Garden Club and master gardeners and staff at the Nature Center on Tuesday, Nov. 20, as part of a citizen outreach. Scott presented a slide show and explanation of how the beetle infects a tree, the life cycle within the tree and how quickly tree die-off can occur.
He explained that entry is no higher than 30 feet from the ground with most around 10 feet. “The heaviest time of mortality is during times of drought,” said Scott. “Trees with thicker bark are attacked more frequently. And with infected large trees, there is a 90 to 95 percent mortality. What we’ve seen in San Diego County is 80 to 95 percent death, in outbreak mode, within six to eight years after infection.”
The news Scott delivered was sobering given what has already happened in San Diego County. Turner said he and Scott were encouraged to see a large turnout of around 35 people, since locals, here each day, can contribute very helpful information by observing local black oaks.
The Garden Club distributed flyers at the Tree Lighting Ceremony requesting that anyone who has purchased oak firewood from a supplier south of Idyllwild in the last three years, who has noticed any oak trees that are not as robust as they had been and are different in appearance from similar and nearby black oaks, and who knows of anyone importing wood to the Hill from an outside source to call Turner’s office at (951) 827-2973.
Third District Supervisor Jeff Stone has also requested that any roadside wood sellers be reported to his office at (951) 698-7326. Roadside vending is illegal in Riverside County.
Why should local property owners be worried? The cost to bring down an infected oak could run from $700 to $10,000 depending on tree size and proximity to structures. Property values and habitat would also be diminished by loss of Hill black oak. “This is an emergency,” Stone said.
Many states have firewood ordinances because of concern over invasive species damage. Those ordinances are strict and enforceable. Currently neither California nor Riverside County has any specific firewood ordinances that require source labeling and limit transportation.
Tree and crew before cutting. Photos by Marshall SmithCAL FIRE crews removed a 140-year-old California black oak (quercus kelloggii), the first local casualty of the Goldspotted Oak Borer that has killed over 80,000 trees in San Diego County. The removal process, which closed Highway 243 in both directions just after 10 a.m. on Wednesday, Nov. 14, took about 45 minutes. GSOB targets California black oak, coast live oak and canyon live oak.
Prior to discovery of the tree, just across Highway 243 from the Italian restaurant La Bella Montagna, the northernmost reach of the highly destructive GSOB was thought to be northern San Diego County, about 40 miles from Idyllwild. Authorities believe the beetles, which share the same genetic characteristics as those in San Diego that have caused such a swath of destruction, were transported in firewood.
CAL FIRE Chief Gregg Bratcher, new agency San Jacinto Mountains forester and Dr. Tom Scott, natural resource specialist, University of California Riverside, were on hand for the felling of the tree by CAL FIRE crews. Scott has been one of the lead scientists in tracking the GSOB spread and destructive path. Crews begin to limb the tree.
GSOB is not native to California. It’s native habitats, where it has been ensconced for many years and held in check by natural predators, is in Guatamala, Mexico and southeastern Arizona. Because it is not native to California, there are no natural predators here to check its spread. Nor are there, at this time, any effective topical pesticides that could arrest its advance.
“This tree was probably already in a lot of trouble [from other pests and funguses] before being hit by GSOB,” said Scott. “It has a lot of beetles in it and would have died no matter what.”
The issue becomes, as Bratcher acknowledged, the coordination of a multi agency response to identify additional infected Hill trees and creation of an effective public education campaign regarding cutting and transportation of firewood, and ways to curtail further spread of the predator. The tree is almost down
The tree cross sections Scott examined after the tree came down will be taken off the Hill to labs in quarantined areas of San Diego County. “By forensically examining it [tree cross sections] we can assign times when the top died and figure out whether the tree was first in trouble [from other pathogens] or whether the beetle killed it,” said Scott. He observed that people in the mountains still need to use firewood, but the issue becomes how to stop movement of diseased wood in a reasonable way.
Bratcher estimated that a rapid response survey of trees in the area of the infected oak would likely begin next week. Crews take tree down, stop traffic Dr. Tom Scott, UCR, photographs a cross section of the trunk. A cross section of the tree shows the red-ish infected area.
Chief Gregg Bratcher, new CAL FIRE San Jacinto Mountain forester, Kevin Turner, University of California, Riverside, GSOB coordinator and Dr. Tom Scott, Natural Resource Specialist, examine the infected Idyllwild tree. The tree, on Highway 243 near the town center, is scheduled for removal Wednesday, Nov. 14. Photo by Marshall Smith
The Goldspotted oak borer, the non-native beetle that has killed more than 80,000 oaks in San Diego County, has been positively identified in an Idyllwild oak, on Highway 243 near the center of town. Currently, entomologists know of no native California predator or insecticidal defense against the tree killer.
A DNA analysis, conducted by the Invasive Species Lab at University of California, Riverside, confirmed the Idyllwild beetle has the same genetic characteristics as the GSOB invaders in San Diego County. Transportation in firewood from San Diego to Idyllwild is the likely culprit, according to forestry officials.
Until this identification, confirmed by CAL FIRE Battalion Chief Julie Hutchinson on Monday, Nov. 12, officials thought the beetle infestation had been confined to San Diego County, with the northernmost reach of this dangerous and highly invasive pest found just north of Julian.
In her press release, Hutchinson wrote, “This new detection of GSOB represents the first large scale movement of the beetle from its known area of infestation in San Diego County, 40 miles to the south. It is believed to have made the jump from San Diego to Idyllwild through the movement of infested firewood.”
Goldspotted Oak Borer found in Idyllwild
CAL FIRE plans to remove the local infected tree on Wednesday, Nov. 14. A multi-agency rapid response team, including members from the U.S. Forest Service, CAL FIRE and University of California, Riverside, will conduct a local survey to determine if there are any other infected trees in the Idyllwild area.
“Leave firewood at home,” advised the CAL FIRE press release. “Do not transport it to recreational cabins, campground or parks. Buy it [firewood] where you burn it.”
Dr. Tom Scott, natural resource specialist at the University of California, Riverside, suggested it would be extremely beneficial if anyone who has imported wood from San Diego County to Idyllwild would share that information with the GSOB task force. The information would be helpful in determining when and specifically from where in the San Diego area the Idyllwild beetle came. This information may help tamp the spread of the deadly pest.
Scott said callers would face no penalties and would assist in what is now a fight to prevent further spread. Call (951) 827-2973 with your information.
Third District Supervisor Jeff Stone said that county Code Enforcement would be put on high alert to target roadside wood sellers in the Idyllwild area. There is a county ordinance (853) that prohibits roadside vending 40 feet from any public right of way, with certain limitations. “We’ll step up Code Enforcement and work with John Snyder, the county agricultural commissioner, to see how we can stop the spread,” Stone said. “If you see roadside wood vendors in the Idyllwild area, call my office (951) 698-7326. This is now an emergency.”
Because GSOB originated outside of California (northern Mexico and southeastern Arizona), there are no natural predators in California to check its progress. Authorities believe it hitchhiked into California in diseased firewood from either Mexico or Arizona.
A University of California, Davis, study estimates that as of February 2012, $8 million in public and private funds had been spent on GSOB mitigation efforts, including dead tree removal, infested wood disposal, closure of parks and campgrounds (due to hazardous dead trees), developing and supporting public outreach and education and engaging government agencies for response and assistance.
For locals seeking to be more actively involved in spotting and tracking GSOB spread, a field training will be offered from 9 a.m. until noon on Tuesday, Dec. 4, at Live Oak County Park, 2746 Reche Road in Fallbrook. Presenters include Dr. Tom Coleman, USDA Forest Service entomologist, Dr. Tom Scott, natural resource specialist, UCR, Kevin Turner, UCR GSOB coordinator and Pat Nolan, County of San Diego pathologist. There is no cost for the workshop. Register online at www.gsob.org or call Jan Gonzales (858) 614-7624. For more GSOB information, visit http://ucanr.edu/sites/gsobinfo/.
In an ongoing campaign to educate the public about the Goldspotted oak borer and the danger it presents to California’s oaks, the California Department of Forestry and Fire Protection declared and mapped a zone of infestation in San Diego County. The declaration and the borders of the zone were adopted at a September meeting of the Board Forestry and Fire Protection and were based on recommendations made by CAL FIRE Chief Ken Pimlott.
At this time, the plan is to foster greater interagency cooperation and to inform and enlist the public in containing the spread of the beetle outside the current infestation zone, according to Board Executive Office George Gentry. It is also to educate the public about the dangers of transporting firewood from the zone to destinations outside the zone. In adopting the zone, the agency considered particular risks to uninfected communities like Idyllwild with large stands of oak.
The educational message being propagated is to burn wood where it is harvested and don’t transport it, especially from San Diego County to any location outside the county. Debarked oak and oak that has been cured for two years pose little to no danger of beetle spread, but those who buy and transport firewood must try to get proof that the wood is harvested from a noninfected area, said Dr. Tom Scott, University of California Riverside natural research specialist and a lead activist in the oak borer battle.
The zone declaration is a step toward greater regulation but at this time the focus is only on education, Scott said. The oak borer infestation zone is clearly demarked and any buyer of firewood from a commercial seller has a right to ask for a bill of sale that shows where it was harvested.
Scott suggested threatened communities, such as Idyllwild, should seek county support for roadside signs that warn firewood importers, both commercial and those bringing it for personal use, that only locally harvested wood is permitted in the community. “Burn only local wood,” said Scott.
He also suggested appealing to the self-interest of vacation rental owners and property managers to advise their clients against firewood importation. “Otherwise owner property values will be affected when oak borer destroys local oak forests,” he said.
The CAL FIRE education campaign is especially critical to educate visitors to Idyllwild about the dangers in bringing firewood from San Diego County. Many San Diego County residents visit Idyllwild. Many have second homes here. Others stay in vacation rentals.
At present, there is no way to know if they are bringing firewood in from the infected zone, Scott noted. There the beetle has destroyed over 80,000 trees since it was discovered in 2002, according to the CAL FIRE news release. Scientists believe the pest emigrated from Mexico and southeastern Arizona into San Diego County, most probably in firewood.
“The insect causes mortality in healthy, mature coast live oak, canyon live oak and California black oak trees,” said Gentry.
Scott said the public is the frontline against oak borer spread. “Firewood is one of the least regulated commodities,” said Scott, noting that no one should buy firewood without asking for source documentation.
