A little known wood-boring beetle is killing oak trees in eastern San Diego County and eventually could pose the same threat in Orange County, says the U.S. Forest Service.
The insect, which was identified only five years ago and is still only going by the proposed name goldspotted oak borer, has been suspected in recent years of killing both Coast live oak and California black oak trees. The suspicion deepened in a newly published study in the Pan-Pacific Entomologist, which says the insect, scientifically known as Agrilus coxalis, killed almost 70 percent of the oaks in a specific area of San Diego County.
"Land managers and scientists are concerned about further spread of the infestation because oaks are the dominant tree species in that area," the Forest Service says in an summary of the study. "Further tree mortality will increase fire danger and decrease wildlife habitat in Southern California.
"They are also concerned (that) drought and climate change will make more oaks susceptible to an insect that is not native to California. Oak trees have a nearly continuous distribution in the state, reaching from the infestation area north to the Oregon border."
An earlier report says that the goldspotted oak borer can be transported from one place to another inside oak that is bundled as firewood and that such firewood should be moved as little as possible.
Scientists aren't certain how the insect spread into California, but it might have arrived in firewood from Mexico over a period of decades and could have begun killing trees in Southern California in 2002, even before the species was formally discovered.OC Register
