Emerald ash borer found in several new locations in northern Willamette Valley

June 25, 2026

(TUALATIN, Ore.) – The tree-killing emerald ash borer (EAB) pest has been confirmed in at least three new Willamette Valley communities this month –in a shopping center parking lot just east of I-5 in Tualatin, in a parking lot right outside Newberg, and at a private residence in Silverton.

The new detections are within the existing EAB quarantine zone covering the five counties where this pest has been found so far. Counties within the quarantined zone are Clackamas, Marion, Multnomah, Washington and Yamhill. By order of the Oregon Department of Agriculture, tree material from ash, olive, and white fringetree must remain within quarantined counties, along with firewood from any hardwood tree.

Oregon Department of Forestry EAB Support Specialist Matt Mills said, “we have long known that EAB would spread from infested sites to nearby areas, so these new detections are not unexpected. Experience from other states shows that four to five years or so after first being detected EAB spreads from pockets of infested ash trees and becomes much more widespread over an entire county or metropolitan area.”

All three reports were made by private individuals who recognized ash trees that were showing signs of EAB infestation and knew to report them on the invasive species hotline at https://oregoninvasiveshotline.org.

Kat Bethea, also an EAB Support Specialist with the Oregon Department of Forestry, said this shows the success of four years of outreach to the public in northwest Oregon with information about EAB and what to expect and where to report sightings.

“We are thankful that people are paying attention to the health of ash trees around them and letting us know when signs point to a possible EAB infestation,” Bethea said.

Bethea added that ODF has sent messages to officials in the affected towns and those in surrounding communities to let them know to keep a close eye on ash trees in their community for signs of EAB.

What the public can do

“This is a good time to identify any ash trees on your property. Decide which ones if any you want to keep and contact a licensed pesticide applicator to begin protective treatment with a systemically injected insecticide,” said Bethea.

Mills said if homeowners plan to remove ash trees already in poor condition, then they should wait until mid-October when adult EAB beetles are no longer flying. “Pre-emptive removal of such trees will allow them to replant with trees that aren’t vulnerable,” he said. “This will start restoring tree canopy and also spreads out the cost of removals. Simply waiting for EAB to start killing trees in your town can become overwhelming in a short period of time and costly.”

Mills said ash trees quickly become brittle and hazardous to climb or work under once they are killed.

“Removal of a dead or rapidly dying ash tree is more dangerous and costly than when it is still alive. That’s why in newly infested areas or areas nearby it’s a best practice to pre-emptively remove any ash trees that are along streets or in parks or yards, and which are in poor condition or planted in the wrong place,” he said.

Mills added that although EAB is spreading naturally through the northern Willamette Valley, people moving firewood more than 10 to 15 miles from an EAB-infested tree risk taking the pest into distant, uninfested areas. “Firewood being moved is a known way EAB is able to travel farther and spread faster than it could on its own. That is why the Oregon Department of Agriculture doesn’t allow hardwood firewood to be moved from quarantined zones.”

For more information on how to identify ash trees or EAB, what the signs of infestation are, and what can be done in response to an infestation, please visit www.OregonEAB.com.

Newberg

The pest was first reported in Yamhill County only two years ago. At that time, a single beetle was found on the county’s northern border with Washington County. This June the Oregon Department of Agriculture’s Max Ragozzino investigated a report called in to the Oregon Invasive Species Hotline. Ragozzino found two trees in a parking lot were heavily infested with EAB. Six others appear to be only lightly infested so far.

Tualatin

After a report came to the hotline about ash trees in a commercial parking lot near I-5 with telltale signs of EAB, ODF was able to visit and confirm that a number of the trees were infested with EAB. The location is especially concerning because it is only about a mile from the Tualatin River, whose banks are shaded by large numbers of Oregon ash.

City of Tualatin Parks Maintenance Manager Tom Steiger states that the city has been following the movement of the emerald ash borer, conducting tests within the city, and learning about treatment and mitigation measures. Additionally, the city has an inventory of where ash trees are located as street trees, and has funding budgeted for a survey along the banks of the Tualatin River and other natural areas, which can help inform next steps in the approach to management and replacement of ash trees within the city.

Silverton

A private pesticide applicator coming to treat an ash tree in a residential neighborhood on the north side of town reported signs of EAB in the tree, which ODF later confirmed. A second report has since come in as well, Mills said.

Single invasive quagga mussel found on shoreline of Prineville Reservoir; No other evidence of quaggas found, intensive monitoring continues

June 23, 2026

Media Contact: Adam Baylor, 503-930-7116, Adam.C.Baylor@ODFW.Oregon.gov

PRINEVILLE, Ore. – A single dead adult quagga mussel was found out of water on the shoreline at Prineville Reservoir on June 6 during a routine survey for aquatic invasive species. This marks the first time that this highly invasive freshwater mussel species has been found in or near an Oregon waterbody.

Only the single quagga mussel was found. Additional intensive surveys by Portland State University (PSU) Center for Lakes and Reservoirs did not find any other mussels along the shoreline at Prineville Reservoir. Test results from water samples and environmental DNA (eDNA) tests by PSU that came back late last week also showed no sign of invasive mussels. It is unknown at this time how the quagga mussel ended up on the shore of the reservoir.

On June 6, PSU crews were conducting surveys at Prineville Reservoir and nearby waterbodies as part of their regular aquatic invasive species surveillance work around the state. On that day, surveyors located the single dead adult quagga mussel (Dreissena bugensis) on shore in sand about one meter above the waterline. They collected it and contacted ODFW, Oregon State Marine Board (OSMB) and the Oregon Invasive Species Council per established protocols.

Since the June 6 detection, ODFW and OSMB, together with federal, state and local partners, have been working under the Oregon Invasive Freshwater Mussel Rapid Response Plan. They have formed a Unified Command to coordinate continued surveillance, sampling and outreach efforts to boaters in Central Oregon and around the state.

This discovery is a serious environmental and economic concern for Oregon and the Pacific Northwest. Invasive quagga mussels are small non-native freshwater mollusks that have caused major problems in the United States since their introduction in the 1980s. They can reproduce extremely quickly and can seriously damage Oregon's waterways. They attach to any hard surface to colonize, clog water intake systems, outcompete native species, and disrupt recreation and aquatic habitats and infrastructure.

"We are taking this finding extremely seriously, but also cautiously as we work to confirm what we're seeing at Prineville Reservoir. We are coordinating closely with our state, federal, tribal, and local partners, and preparing to move quickly based on the evidence we find," said Keith DeHart, ODFW Aquatic Invasive Species Coordinator. "Our top priority is protecting Oregon's waters while making sure every action we take is grounded in the best available information."

During surveys by PSU crews conducted in late May and early June 2026 at Prineville Reservoir, technicians completed six dock inspections covering 182 meters and surveyed 22 shorelines totaling nearly 1,500 meters. They also performed 57 mussel larva (veliger) tows—53 boat-based and four stationary near the dam—filtering more than 296,000 liters of water overall. All surveys and laboratory results from the water samples as well as Environmental DNA (eDNA) samples were negative for invasive mussels.

On June 18, ODFW staff completed inspections of two floating restrooms and their associated buoys as well as two moored vessels on Prineville Reservoir with all checks following standard invasive species protocols. No invasive freshwater mussels were detected on any structures or vessels during the survey.

Monitoring teams will continue routine intensive sampling efforts moving forward to ensure early detection and subsequent rapid response if quagga mussels are present.

Clean, Drain, Dry
Recreational boats are known to be a major source of freshwater invasive mussel spread in the United States. Inspections have intercepted boats fouled by live invasive mussels prior to launching in Northwest waters a number of times in recent years. In April, ODFW staff at the Ashland Boat Inspection Station found golden mussels on a watercraft headed from the Sacramento River Delta to Oregon and were able to decontaminate the boat before it reached an Oregon waterbody.

To prevent potential dispersal of freshwater invasive mussels, boaters should: CLEAN all boats, trailers, and other equipment after leaving a lake or stream. DRAIN all water from vessels and allow them to DRY before launching into another waterbody.

Boaters are also reminded that they are required to stop at check stations for inspection. Check stations are currently located in Brookings, Ashland, Klamath Falls, Ontario and Umatilla. A roving check station will also be at boat ramps around Prineville Reservoir and central Oregon periodically in coming weeks to inspect watercraft for invasives.

Check stations and other invasive species surveillance are funded by proceeds generated by the Aquatic Invasive Species Permit and Waterway Access Permits.

ODFW and partners will continue to monitor the situation at Prineville Reservoir and regional waterbodies, allocating additional resources as needed. Expanded water and shoreline surveys are being conducted to facilitate early detection and rapid response to any signs of invasive mussels.

Public outreach including watercraft inspections is increasing. Inspections along with education materials and signage are intended to reinforce the Clean, Drain, Dry protocol with Oregon boaters.

"Continued vigilance and cooperation from the public are vital to protecting Oregon's waters and keeping recreation areas open," said DeHart.

There are no plans to close Prineville Reservoir at this time, as all structures and vessels inspected showed no visible mussels or signs of invasive freshwater species.

While it remains unlikely that reservoir users will encounter mussels, the public is encouraged to report any suspicious sightings to the Oregon Invasive Species Hotline at 1‑866‑INVADER or online at https://oregoninvasiveshotline.org to support ongoing monitoring and early detection efforts.

A single quagga mussel found on June 6 along the shoreline of Prineville Reservoir—displaying its brown and tan striped shell pattern. (Photo by PSU)

Invasive golden mussels intercepted on incoming watercraft at Ashland inspection station

SALEM, Ore. – ODFW staff at the Ashland Boat Inspection Station found golden mussels on a watercraft that was being transported to a new owner from the Sacramento River Delta to Oregon on April 4. The watercraft was decontaminated at the inspection station and all golden mussels attached to the boat were properly disposed.

This is the first detection of adult golden mussels being transported into Oregon. Golden mussels were detected for the first time in North America in 2024 and the threat to Oregon is very serious.

Golden mussels are similar to zebra or quagga mussels, but they can establish in a much wider range of temperatures and can tolerate some water salinity. They feed heavily on microscopic aquatic plants and animals that are essential food sources for native species and sport fish.

Invasive freshwater mussels can damage water infrastructure, such as irrigation and hydropower systems, and also degrade water quality and limit recreational activities such as fishing and boating.

"Early detection like this shows how critical watercraft inspections are to protecting our fisheries, infrastructure, and agriculture," said ODFW Invasive Species Coordinator Keith DeHart. "We are grateful for the boat owner's cooperation throughout the inspection and decontamination process. Their willingness to follow regulations and assist staff played an important role in helping prevent the potential spread of invasive mussels into Oregon's waters."

It is the law in Oregon that any vehicle transporting a watercraft is required to stop at any open watercraft inspection stations for aquatic invasive species inspections.

Watercraft owners should be aware of where inspections stations are located around Oregon. Stations are open if orange, "Boat Inspection Ahead," signs are posted, followed by "Inspection Required for All Watercraft."

Visit MyODFW.com for more information about the Aquatic Invasive Species Prevention Program and Waterway Access permits.

ODFW, in partnership with the Center for Lakes and Reservoirs at Portland State University, has not detected invasive freshwater mussels in any of Oregon's waterways thanks to responsible boaters and inspection station crews. However, Oregon is still at risk of an invasion. In 2025 crews decontaminated 12 watercraft carrying invasive freshwater mussels and intercepted an additional 295 watercraft for other types of aquatic biofouling such as Eurasian Watermilfoil.

Since the start of the Watercraft Inspection Stations program in 2010, ODFW has inspected 246,748 watercraft and intercepted 185 watercraft with invasive freshwater mussels and 3,758 watercraft with other types of aquatic biofouling.

Last month, quagga mussels were found on a watercraft entering Oregon, the first confirmed instance in 2026 of invasive freshwater mussels being detected on a boat entering the state.

Inspection station locations and operating hours:

Ashland: I-5 at the Ashland Port of Entry. Open daily, year-round, during daylight hours.

Ontario: I-84 at the Ontario Rest Area. Open daily, year-round, during daylight hours.

Seasonal inspection stations located in Brookings, Klamath Falls, Umatilla, and at Owyhee Reservoir will be opening the first week of May. ODFW will also have roving inspection crews working boat ramps and other access points around the state this year.

If you find invasive freshwater mussels on a vessel, please help protect Oregon and report them to the Oregon Invasive Species hotline by calling 1-866-INVADER or visiting https://oregoninvasiveshotline.org.

Photos:

Invasive golden mussels were found on a watercraft being transported into Oregon from the Sacramento River Delta on April 4, 2026. ODFW photo.

Invasive golden mussels removed from a watercraft that was transported into Oregon from the Sacramento River Delta on April 4, 2026. ODFW photo.

Invasive golden mussels were found on a watercraft that was transported into Oregon from the Sacramento River Delta on April 4, 2026. ODFW photo.

OREGON INVASIVE SPECIES COUNCIL ANNOUNCES 2024-2025 AWARD WINNERS

SALEM, Oregon - Every biennium, the Oregon Invasive Species Council (OISC) highlights, through special recognition awards, those people and organizations protecting Oregon’s natural resources, economy, and quality of life from the devastating effects of invasive species.

All OISC award winners will be recognized at an luncheon on March 17, 2026, from 12pm-2pm in Salem as part of the OISC’s Annual Winter Meeting. If you are interested in attending, please reach out to the OISC Coordinator at coordinator@oregoninvasivespeciescouncil.org. For more information on this meeting and other Council events please visit the Council website. 

Eagle Eye Award  |  Amber Basting, Oregon Department of Agriculture and Peter Van Oss, Teragan & Associates, Inc
This award was created to recognize the person or persons reporting the most critical sightings of an invasive species. This year the OISC recognizes two individuals:

Two years ago, during a railway survey in The Dalles, Amber Basting discovered a spotted lanternfly (SLF) egg mass. SLF egg masses are notoriously difficult to detect, as their coloration and texture easily blend into the surfaces where egg masses are laid (such as tree bark and rusted metal). Amber's interception was exceptional in that the egg mass was found on a rusted rail car, up on the higher edges of the car. To the untrained and non-committal eye, this would have easily been missed. This was the first and only egg mass found in Oregon to date. This early interception removed the possibility of this egg mass hatching in some unknown location in Oregon which could have resulted in a population going unchecked for months or years thereafter.

On July 25, 2025, Peer Van Oss, an arborist with Teragan & Associates,  used the OISC Hotline to report emerald ash borer in a landscape ash in the parking lot of David Douglas Aquatics Center in east Portland.. This was the first positive emerald ash borer report in both the City of Portland and Multnomah County. Peter’s prior training, early detection and proper reporting to the OISC Hotline led to swift response by state and local officials.

Student Award  |  Allison Monroe, Oregon State University
This award, presented to the Oregon student making a difference in protecting Oregon from invasive species, goes to Allison Monroe for her contribution to protecting Oregon through early detection and prevention of Mediterranean oak borer (MOB).  Allison's work addresses one of the most pressing emerging threats to Oregon white oak ecosystems in the Willamette Valley, where oaks function as keystone species with deep ecological and cultural importance. At a time when MOB remains poorly understood in the Pacific Northwest, Allison has generated some of the first regionally relevant data on its presence, spread, and colonization dynamics in our oak-dominated landscapes. Rather than reacting to widespread damage, her work focuses on identifying invasion risk at its earliest stages when management intervention is still possible and most effective. 

Sandra Denyes Diedrich Award  |  Jacob Rose, Portland State University and Courtney Gattuso, Cascade Pacific 

Created in honor of Sandy Diedrich, the indefatigable founder of the Forest Park Ivy Removal Project aka the No Ivy League, is presented to the person(s) or organization making an outstanding contribution to protecting Oregon from invasive species. 

This year the Council has chosen to recognize two people who, working together as a team, have gone above and beyond to ensure the continuing existence and success of the Oregon Invasive Species Reporting Hotline. Jacob Rose has done an outstanding job navigating the technical re-homing of the Oregon Invasive Species Hotline, a surprise hurdle for a long-running and well-loved tool in Oregon's invasive species response toolkit. The successful outcome was steered by Jacob's knowledgeable and personable leadership throughout the transition. Working with Jacob to keep the Hotline funded, Courtney Gattuso has shouldered the mantle of primary fundraiser for this critical reporting tool. Without Courtney’s tireless dedication to keeping Jacob and the Hotline funded, the OISC would not be able to provide the public or knowledgeable respondents with the robust reporting tool that has led to numerous positive reports of invasive species of concern, including one of this year’s Eagle Eye Award winners’ EAB report.

Outstanding Agency Partner Award  |  Michelle Delepine, West Multnomah Soil and Water Conservation District

In recognition of her efforts, the OISC awards Michelle Delepine, Conservationist and Invasive Species Program Manager at West Multnomah Soil and Water Conservation District, with the Outstanding Agency Partner Award. Serving in this role since 2014, Michelle has built long-standing, cross-jurisdictional partnerships that strengthen invasive species prevention and management across Oregon and the broader Pacific Northwest. Her impact as an agency partner is equally evident in the 4-County Cooperative Weed Management Area. As a Steering Committee member from 2014 to 2023 and Chair from 2017 to 2019, Michelle helped expand both the reach and stability of this multi-agency partnership. 

“Michelle Delepine exemplifies the spirit of the Outstanding Agency Partner Award. Her career is defined by collaboration, capacity-building, and a deep commitment to shared solutions. Through her leadership, agencies are more connected, management is more coordinated, and the collective response to invasive species is stronger and more effective.”

- Eleanor Greene, West Multnomah Soil and Water Conservation District

Outstanding Agency Partner Award | Honorable Mentions 

The OISC received numerous excellent nominations for Outstanding Agency Partner and wishes to recognize the important work of the following partners: 

Carri Pirosko, Oregon Department of Agriculture | For leadership on invasive weeds in southern Oregon.

Drew Donahue, Clackamas Soil and Water Conservation District | For her involvement in creating a network of cooperators in Clackamas County to prepare for and respond to emerald ash borer. 

Georgia McAlister, City of Wilsonville* | For being an essential partner on the Mediterranean Oak Borer Task Force and developing a MOB response plan for the City of Wilsonville.

Patricia “Bonnie” Rasmussen, Oregon Department of Agriculture | For her actions and leadership on Palmer amaranth, an emergent A-listed noxious weed, in Malheur and Harney Counties.

Service Award  |  Karen Lousie Ripley, U.S. Forest Service (1964-2005)
The prestigious Service Award is presented to the person or persons who have demonstrated extraordinary service to the Oregon Invasive Species Council. The OISC wishes to recognize Karen for her many years of work and dedication to protecting Oregon's natural resources from invasive species with her leadership, vision and commitment to excellence. She will be sorely missed. She had an outsized and lasting impact on everyone in the invasive forest pest world and beyond. Karen was the Forest Health Monitoring and Invasive Insects coordinator for the Forest Health Protection group within the Pacific Northwest Region State, Private, and Tribal Forestry Program and served for eight years on the Oregon Invasive Species Council. Karen was instrumental in the development of the Oregon Emerald Ash Borer Readiness and Response Plan along with the formation of the Oregon Emerald Ash Borer Task Force, both of which now serve as models for similar state efforts in the region. She was also the first person to identify the presence of the Mediterranean oak borer in Oregon.

Chinese mitten crab found in Willamette River near Portland; ODFW asks for help to identify invasive species in Oregon’s waters

SALEM, Ore. – A Chinese mitten crab, a prohibited species in Oregon, was found in the Willamette River near the Sellwood Bridge and reported to ODFW on Nov. 17.

The crab was spotted in shallow water and captured by hand. It was alive and not released back into the river. Mitten crab is a non-native crab species that lives its adult life in freshwater and migrates to brackish water to breed, unlike Oregon's native crab species that live in the ocean, bays, and estuaries.

This recent confirmation is concerning for ODFW as another Chinese mitten crab was found in Oregon waters in April 2025 in a different location – marking the second confirmation of this invasive species in Oregon.

ODFW biologists are working with the U.S. Fish and Wildlife Service, Portland State's Center for Lakes and Reservoirs and the Oregon Invasive Species Council to determine if other mitten crabs are in the Willamette River.

Detection methods include setting up artificial habitats to attract mitten crabs and collecting water and substrate samples to look for environmental genetic markers specific to Chinese mitten crab. PSU initiated a monitoring program for mitten crab in the Columbia and Willamette rivers by conducting shoreline walks and looking for signs of mitten crab including molted carapaces (top shell).

It is unlawful to possess mitten crabs in Oregon, so they are unlawful to sell in Oregon. There is a risk of mitten crabs being illegally imported and sold in the food trade and then released alive into Oregon waters. The agency asks the public to report any suspected unlawful sales.

It is important to correctly identify this species and report it to 1-866-INVADER or report it online via the Oregon Invasive Species reporting hotline form. Photographs can be submitted through the hotline and people are encouraged to do so as crab identification can be difficult and native crabs have been misidentified as invasive.

Chinese mitten crabs are known to burrow into dikes, levees or stream banks which can increase erosion and damage flood control and water supply systems. These medium-sized crabs, about 3-inches wide, prey on native species, consume fish eggs and compete for food, potentially impacting native fish and crayfish populations.

Mitten crabs vary in color from brownish orange to greenish brown and are named for their hairy mitten-like features located on the outside of their claws. They have a notch between their eyes and four spines on each side of the carapace.

When identifying non-native mitten crabs, it is important to note that the hairy shore crab, a native species to Oregon, also have a patch of hair on the inside of their claws.

Photo submitted to ODFW from most recent invasive species report (Nov. 17, 2025).

Visual identification guide for crabs in Oregon – be sure to not harm native species.

Link to Chinese mitten crab identification illustration

ODFW Contact

Adam Baylor, 503-930-7116, adam.c.baylor@odfw.oregon.gov