Posts Tagged: gold spotted oak borer
UC IPM Releases Management Guidelines for Goldspotted Oak Borer
UC IPM released a new Pest Note in January 2013 on the goldspotted oak borer. This Pest Note has the first official UC guidelines for managing the pest.
The most seriously damaged oaks are those in the red oak group including coast live oak, Quercus agrifolia, and black oak, Q. kelloggi. It also infests canyon live oak, Q. chrysolepis but has not been found to kill the other native oak species in the area, the Englemann oak, Q. englemanni. So far losses have been most serious in parks and forested areas, but landscape trees are also being killed.
A new Pest Note from the UC IPM program outlines management guidelines for this serious pest. Flatheaded borers such as GSOB are difficult to manage and seriously infested trees cannot be saved. The primary way GSOB spreads into new areas is through the movement of infested wood and the authors recommend leaving infested wood on site for 2 years. If wood is to be moved, the Pest Note provides guidelines for treating it through containment, grinding, and debarking. Guidelines for replanting infested areas, less susceptible oak species, biological control, insecticide applications and developing GSOB management plans are also described.
Many other borers attack oaks but do not kill trees. GSOB infested trees can be distinguished by the characteristic D-shaped emergence holes it leaves behind. A special feature of the Pest Note is a table illustrating the emergence holes of borer species on southern California oaks. Many photos are also included.
The information in this Pest Note: Goldspotted Oak Borer is based primarily on research studies by the authors: Mary Louise Flint (UCIPM and Entomology/UC Davis), Tom Coleman and Steve Seybold (USDA/US Forest Service), and Mike Jones (Entomology/UC Davis). Find it at http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74163.html
Don’t move firewood and pests
Reposted from ucanr.edu
“Buy firewood from a local source close to your home to prevent the spread of insects and diseases, such as the goldspotted oak borer, sudden oak death and emerald ash borer,” said Tom Scott, a UC Cooperative Extension specialist based at UC Riverside who studies these invasive pests.
“Firewood is one of the least-regulated natural resource industries in California,” said Scott, “but this is a situation where the university can play a critical role in changing behavior through research and education rather than regulation.”
Scott and his UC Cooperative Extension colleagues are working with the U.S. Forest Service, the California Firewood Task Force and other agencies to educate and discourage woodcutters, arborists, firewood dealers and consumers from transporting infested wood.
“Many people don’t realize that firewood can harbor harmful insects and plant pathogens. Moving around infested wood can introduce those pests and pathogens to new areas where they might take hold and could have devastating impacts to trees, our natural resources and local communities,” said Don Owen, California Firewood Task Force chair and CAL FIRE forest pest specialist based in Redding.
“Even wood that looks safe can harbor destructive pests,” cautioned Janice Alexander, UC Cooperative Extension sudden oak death outreach coordinator in Marin County.
For example, female goldspotted oak borers lay eggs in cracks and crevices of oak bark, and the larvae burrow into the cambium of the tree to feed so they may not be visible.
The goldspotted oak borer has killed more than 80,000 oak trees in San Diego County in the last decade and Scott hopes it can be contained in that region. The half-inch-long beetle is native to Arizona but not to California and likely traveled in a load of infested firewood, according to Scott.
In his research, Scott has found outbreaks of goldspotted oak borer 20 miles from the infested area, which leads him to believe movement in firewood is the most likely reason for the beetle leap-frogging miles of healthy oak woodlands to end up in places like La Jolla. In communities where people harvest local trees for firewood, oaks have remained relatively beetle-free, Scott said.
In addition to concealing goldspotted oak borer, firewood may harbor other destructive invasive species such as emerald ash borer or the pathogen that causes sudden oak death. Sudden oak death has killed more than a million oak and tanoak trees in 14 coastal California counties, from Monterey to Humboldt. The highly destructive emerald ash borer has been identified in Michigan, Indiana, Ohio and Illinois, but not California.
“Our best defense against the GSOB outbreak is the enlightened self-interest of Californians purchasing firewood,” Scott added. “If you want to protect the oaks around your house, neighborhood, and nearby woodlands, make sure that you’re not buying wood that could contain these beetles.”
In a broader sense, buy firewood from reputable dealers, from local sources whenever possible – and try to make sure that the wood you buy has been properly seasoned and doesn’t contain pests.
Tips for buying oak firewood
- Don’t buy green firewood from unknown sources, it has the highest chance of containing pests and pathogens.
- Ask where the firewood originated. If it isn’t local, ask what precautions the seller has taken to ensure that the firewood is free of harmful insects and disease or consider buying from another local source.
- Wood should preferably be bark-free, or have been dried and cured for one year prior to movement.
- If you see D-shaped exit holes, be reluctant to buy unless you know the wood has dried for at least a year or longer.
For more information about the pests and diseases that threaten California’s oaks, visit these websites:
Contact: Katie Palmieri,California Firewood Task Force, (510) 847-5482, kpalmieri@berkeley.edu
Firewood movement leading cause of oak infestation
A catastrophic infestation of the goldspotted oak borer, which has killed more than 80,000 oak trees in San Diego County in the last decade, might be contained by controlling the movement of oak firewood from that region, according to researchers at UC Riverside.
“This may be the biggest oak mortality event since the Pleistocene (12,000 years ago),” said Tom Scott, a natural resource specialist. “If we can keep firewood from moving out of the region, we may be able to stop one of the biggest invasive pests to reach California in a long time.”
A cadre of UC researchers is leading the effort to assess and control the unprecedented infestation, in partnership with the U.S. Forest Service. Scott and others are working to identify where the infestation began, how it is spreading through southern California’s oak woodlands, and what trees might be resistant. In October 2010 Scott and other UCR researchers received $635,000 of a $1.5 million grant of federal stimulus money awarded to study the goldspotted oak borer and sudden oak death.
The goldspotted oak borer (Agrilus auroguttatus), which is native to Arizona but not California, likely traveled across the desert in a load of infested firewood, possibly as early as the mid-1990s, Scott said. Researchers have confirmed the presence of the beetle as early as 2000 near the towns of Descanso and Guatay, where nearly every oak tree is infested.
The half-inch-long beetle attacks mature coast live oaks (Quercus agrifolia), California black oaks (Quercus kelloggii) and canyon live oaks (Quercus chrysolepis). Female beetles lay eggs in cracks and crevices of oak bark, and the larvae burrow into the cambium of the tree to feed, irreparably damaging the water- and food-conducting tissues and ultimately killing the tree. Adult beetles bore out through the bark, leaving a D-shaped hole when they exit.
Scott and Kevin Turner, goldspotted oak borer coordinator for UC Agricultural and Natural Resources (ANR) at UCR, said that field studies in San Diego County in the last six months point strongly to the transportation of infested oak firewood as the source of the invasion that threatens 10 million acres of red oak woodlands in California.
Outbreaks have been found 20 miles from the infestation area, implicating firewood as the most likely reason for the beetle infestation leap-frogging miles of healthy oak woodlands to end up in places like La Jolla. In contrast, communities that harvest their own trees for firewood have remained relatively beetle-free, even as adjacent areas suffer unprecedented rates of oak mortality. Both examples support the growing conviction that the movement of infested firewood is the primary means by which the beetles are spreading, Scott said.
California’s coast live oaks, black oaks and canyon live oaks seem to have no resistance to the goldspotted oak borer and, so far, no natural enemies of the beetle have been found in the state.
The devastation can be measured in costs to communities and property owners for tree removal, the loss of recreation areas and wildlife habitat, lower property values and greater risk of wildfires. The three oaks under attack may be the single most important trees used by wildlife for food and cover in California forests and rangelands.
Most of the dead and dying trees are massive, with trunks 5 and 6 feet in diameter, and are 150 to 250 years old. The cost of removing one infested tree next to a home or in a campground can range from $700 to $10,000. The cost of removing dead and dying trees in San Diego County alone could run into the tens of millions of dollars. In Ohio, which has experienced similar losses from the emerald ash borer, several small cities went bankrupt because of tree removal costs associated with that beetle, Scott said.
So many oaks have died in the Burnt Rancheria campground on the Cleveland National Forest – a favorite spot for campers who favored the shade of a dense canopy of coast live oaks – that the Forest Service has had to erect shade structures. Other state and county parks in the region have suffered equally devastating losses.
Turner said an Early Warning System of community volunteers launched in San Diego County now includes representatives from every southern California county as far north as Ventura. Those volunteers are trained to monitor the health of oak trees in their communities and report any unusual changes.
At the same time, a network of UC Cooperative Extension, ANR, U.S. Forest Service and other agencies in the region is working with woodcutters, arborists and consumers to discourage the sale and transportation of infested wood. Wood that is bark-free or that has dried and cured for at least one year is generally safe to transport, Scott said. This relatively small change in firewood-handling methods could save a statewide resource without jeopardizing the firewood industry, he said.
Local, state and federal agencies recognize that firewood production is one of the least-regulated industries in California, and view UC Cooperative Extension education as the best means of stopping goldspotted oak borer movement in firewood.
“Quarantines don’t work, but enlightened self-interest can keep oak woodland residents from importing GSOB-infested firewood,” Scott said. “This is a situation where the university can play a critical role in changing behavior through research and education rather than regulation.”
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Tips for buying oak firewood
• Ask where the firewood comes from. If the source is San Diego County, ask what precautions the seller has taken about the goldspotted oak borer.
• Wood should preferably be bark-free, or it not, have been dried and cured for one year prior to movement.
• If you see D-shaped exit holes, be reluctant to buy unless you know the wood has dried for a year or longer.
For images or to read the UC Riverside press release, go to http://newsroom.ucr.edu/2715.
Gold spotted oak borer