Lea Nash was talking to her neighbor about Oregon's newest pest when one flew into her neck or so she thought.

Standing near their Eugene homes close to River Road, the bug bounced off her neck and she assumed it was a bee. But looking down to where the bug lay stunned, she thought she recognized its color from a recent article in The Register-Guard.

Nash caught the metallic green bug in a jar. She was sure it was an emerald ash borer, the invasive beetle species that has decimated North American ash tree populations over the past 20 years and recently was found in Oregon for the first time.

Though Nash wrongly identified the insect she'd captured, Nash can be forgiven for missing the subtle differences.

The bug was a brilliant metallic green, just like the invasive emerald ash borer, scientific name Agrilus planipennis. But with just a bit more information at her disposal, Nash may have noticed the black spots on her specimen's wing covers.

What actually crashed into Nash's neck that day was later identified a western cedar border, scientific name Trachykele blondeli, another in the buprestidae family of wood-boring beetles often called "jewel beetles" for their metallic hues.

"I've got it in the jar and I'm thinking, 'This really looks like that thing,'" Nash said. "You've got to have your glasses on."

Though the western cedar borer is one of the insects most commonly confused with emerald ash borer, it's an Oregon native and doesn't create the kind of ecological disaster local foresters now are expecting its invasive cousin to cause.

Emerald ash borer, sometimes referred to as EAB, was reported in Oregon for the first time in late June. Though there's little hope the invasive Asian insect can be rooted out of Oregon before it spreads through the state and kills off most ash trees in coming years, state and municipal foresters want to keep track of it so as to mitigate or slow the damage.

"EAB has become the most destructive and costliest forest pest ever to invade North America, ODF Invasive Species Specialist Wyatt Williams said in the July announcement. At least fiveashspecies native to the central U.S. have become critically endangered as EAB spreads across the country killing hundreds of millions of urban and wildashtrees.

Extinction-level threat:Invasive beetle expected to decimate Oregon ash trees

EAB over the last 20 years has killed more than 100 million North America ash trees, with nearly 99% of infested trees succumbing to the beetle.

Only the Oregon ash is native to Oregon, a species important to riparian areas across the Willamette Valley and beyond. But dozens of other ash species are planted throughout Oregon cities, and all are at risk.

In Eugene alone, there are more than 9,000 ash trees on city streets and in city parks, according to EugeneUrban Forestry SupervisorEric DeBord. Ash trees make up about 8.5% of the city's approximately 65,000 street trees, or about 5,500 of the total.

In Salem, about 1,700 of the 32,000 street trees the city urban forester has inventoried are species of ash that are vulnerable to the emerald ash borer.

It is not known exactly how many ash trees are growing throughout the state or in local natural areas.

The discovery of EAB in Forest Grove in Washington County triggered the use of a statewide response plan to contain the damage. As of July 26, the Oregon Invasive Species Council Hotline had received 174 potential reports of EAB, according to the Oregon Department of Forestry. ODF is not tracking reports made to other agencies, but is aware that many have been made.

A major focus this summer is determining the extent of the EAB infestation in Washington County and following up on any leads about other possible locations as they are reported, according to ODF. The U.S. Department of Agriculture is placing traps in the Forest Grove area and engaging withODF,Tualatin and Columbia Soil and Water Conservation Districts, Clean Water Services and the Tualatin River National Wildlife Refuge Center.

ODFs urban forestry program is also working to get information to urban foresters in cities and towns, according to ODF. Staff hosted a well-attended webinar on EAB July 21 for urban foresters around the state. ODF is encouraging cities that dont know how many ash trees they have to quickly inventory their trees to help them assess their risk from EAB.

ODF has also held in-person information-sharing meetings at the first-reported infestation site with OSU Forestry Extension, local officials from Forest Grove and Washington County conservation and soil and water agencies, he said.

While ODF and other agencies want help from the public tracking down EAB, resources are limited and the hunt can be best helped when reports are made by those who know what to look for. The OISC hotline online allows uploading of photos of tree damage and specimens so reports can be evaluated and specimens passed to experts for confirmation.

ODF reported one additional emerald ash borer-infested tree has been discovered near the original detection in Forest Grove because of a hotline report. No other investigated reports as of July 27 were confirmed to be EAB, according to ODF.

To the layperson, many other beetle species that are metallic green can look similar to invasive emerald ash borer, ODF forest entomologist Christine Buhl said in an email.

Keep in mind:

The most common beetles that people confuse with EAB are some of our natives, such as:

"Look closely at side-by-side images and you can see there are size, shape and color differences. These two beetles also do not attack ash. Instead, they feed on conifers, but are not major pests," Buhl said.

A number of species native to Oregon are in the same genus (Agrilus) as emerald ash borer and are also confused for them include:

"These other species closely resemble EAB in shape and size but are brown or blue-ish (not green), and none attack ash. They are considered secondary pests of other kinds of broadleaved trees. Buhl said they're viewed as indicators of preexisting tree stress on their preferred hosts, not primary causes of tree death," Buhl said.

"Color is a key identifier since EAB is the only beetle in the Northwest that is entirely brilliant emerald green," Buhl said. "The rest are more pale green, brown or green with stripes of other colors. Entomologists use keys based on physiological features to more accurately make an identification."

The preferred hosts of non-EAB beetles that look somewhat like EAB are other broadleaved or cone-bearing trees.

"Some are generalists feeding on a variety of trees and others feed only on one type of tree," she said. "Typically they infest trees that are already dying or dead. They help decompose those trees, speeding up the recycling of nutrients from the dead wood into the forest. Bronze birch borer, however, can attack stressed birch trees and cause their death."

"All of these non-EAB species are harmless to people, pets and animals. In some cases they are beneficial in helping break down wooden snags to build forest soils," Buhl explained.

"Some, such as bronze birch borer and flat-headed fir borer, are often found in stressed trees and can add to a trees stress. But they are usually unable to develop in healthy trees and must take advantage of dead, dying and heavily stressed trees. Bronze birch borer is attracted to drought-stressed birch trees and can hasten their death. But those trees would likely have died eventually on their own due to heat and drought stress."

"Definitely not," Buhl said. "They are harmless to people, pets and animals. Some wood-boring insects can be found in dying trees but they arent the cause of the trees death they are only in the trees because those trees are dying or died from other causes.

"Also, many wood borers are useful in helping wood decay faster to return nutrients back to the forest floor for other plants to use.

"In addition, the metallic wood-boring beetle family includes some of Oregons most spectacular insects, well-deserving of the other name for the family: the jewel beetles."

It's expected EAB will continue to spread throughout Oregon over the coming years, though the peak season for the beetle to emerge from trees will end with the summer.

Ash trees that look to be in decline may be an indicator EAB is present, and D-shaped holes on the truck are clear signs the invasive beetle has emerged from the tree.

Oregonians who suspect they've found an infested tree or an specimen they are confident is EAB should contact the Oregon Invasive Species Council Hotline. Reports can be made by calling 1-866-INVADER or online at https://oregoninvasiveshotline.org and click on "Report Now."

Contact reporter Adam Duvernay at aduvernay@registerguard.com. Follow on Twitter @DuvernayOR.

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