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A tiny but destructive pest has shown up in Portland after lurking in towns around the city proper since at least 2022: the emerald ash borer.
An iridescent green beetle, the emerald ash borer wreaks havoc on ash trees, as WW reported last month. Females lay their eggs in the bark crannies on ash trees. The larvae hatch and eat the xylem and phloem, structures that carry water and nutrients, eventually killing the tree.
The Oregon Department of Forestry discovered an emerald ash borer in a tree in the parking lot at the David Douglas Aquatics Center in the Hazelwood neighborhood deep in Northeast Portland. Peter Van Oss, a private arborist with Teragan & Associates, had noticed a sickly ash there and suspected that it might be infested with the voracious bug.
Native to eastern Northern China, Russian and Mongolia, Oregon’s first emerald ash borer was discovered at a school in Forest Grove in 2022.
In addition to Hazelwood, emerald ash borers were also found this year at: Hazeldale Park about a mile west of Beaverton; Killin Wetlands Nature Park near Banks; 5 miles northwest of Yamhill; 3 miles southeast of Oregon City; and on Bureau of Land Management land east of Scotts Mills.
“The pattern of spread in the Eastern U.S. has been that populations at first increase slowly and the rate of natural spread is slow,” said Cody Holthouse, manager of the Oregon Department of Agriculture’s Insect Pest Prevention and Management Program. “But within a few years there is a rapid build-up in the population and it spreads in all directions at a faster pace. That’s exactly what we’re starting to see with these detections.”
(Correction: The original version of this story said the emerald ash borer was found in Forest Grove in 2002. It was found in 2022. Willamette Week regrets the error.)
