The emerald ash borer (EAB), a tiny green beetle from eastern Asia that is killing ash trees across America, has been found in Multnomah County and several areas in the Portland metro area.
A private arborist with Teragan and Associates noticed an ailing green ash tree in the parking lot of David Douglas Aquatics Center in the Hazelwood-Mill Park area. Van Oss suspected it might be infected with EAB and notified officials.
City and state officials inspected the tree and saw signs of EAB infestation, including die back at the top and cerpantine gallery marks under the bark. A single adult insect was trapped and sent to the U.S. Department of Agriculture Animal Plant Health Inspection Service’s Plant Pathogen Confirmatory Diagnostics Laboratory in Maryland, which confirmed it was EAB.
Other new sites in the metro area where EAB was found this summer:
- Hazeldale Park about a mile west of Beaverton.
- Killin Wetlands Nature Park near Banks in western Washington County.
- Five miles northwest of the town of Yamhill in Yamhill County.
- Three miles southeast of Oregon City in Clackamas County.
- Bureau of Land Management-administered land east of Scotts Mills in Clackamas County.
The discovery in southeast Portland puts all of Multnomah County into the EAB quarantine zone, said Cody Holthouse, manager of the Oregon Dept. of Agriculture’s Insect Pest Prevention and Management Program. Other quarantined counties include Clackamas, Washington, Marion, and Yamhill counties.
“Quarantine is designed to prevent humans from spreading EAB by limiting movement of firewood or any other plant materials from ash, olive or white fringetree (Chionanthus virginicus),” said Holthouse.
If you think you’ve seen an emerald ash borer, ODF and ODA ask that you first make sure it’s not a common look-alike bug.
“You can find a good description and photos comparing EAB to other common insects in Oregon that are also green in color at OregonEAB.com,” said Oregon Deparment of Forestry EAB Specialist Kat Bethea. “If you can capture the beetle in a jar or other container that’s ideal, but at least try and take a clear, close-up photo. This helps us identify the insect in question much more easily.”
Bethea said people suspecting they’ve found EAB should report it over the phone to 1-866-INVADER or online at https://OregonInvasivesHotline.org/Reports/Create. Attaching a clear photo is important. Bethea said people who know they have an ash tree and notice a decline should report it the same way.
“Any ash tree can be infested, including native Oregon ash as well as non-native street, park and yard trees. Signs of infestation include thinning and yellowing leaves, bark splitting, D-shaped holes in the tree bark, and shoots from buds on the trunk or branches,” said Bethea.
Matt Mills, who is also an EAB Specialist with ODF, said, “You can find whether or not you’re in an EAB-infested area or close to one by checking an online map we’ve created. It shows the five counties where firewood from hardwood trees cannot be removed. That quarantine also covers any part of ash, olive or white fringetree (Chionanthus virginicus).”
People who want to protect their ash trees before they become infested should consider the same treatment Beaverton and Salem are using to protect their public ash trees. “The insecticide is injected at the base of the trunk and gets taken up into the tree canopy and is quite effective at protecting the tree from both adults and larvae,” said Mills.