State begins annual survey for over 130 invasive pests

OLYMPIA – Seasonal staff are starting to disperse throughout the state to set traps as part of the Washington State Department of Agriculture (WSDA) Pest Program’s annual search for invasive species.

Each year, WSDA surveys for over 130 insects, weeds, and plant pathogens. While some of these pests, such as spongy moth, have been found in the state, most of these pests have not yet been found in Washington but could threaten agriculture or the environment should they establish here.

Top among the department’s pest priorities this year is Japanese beetle. WSDA has been engaging in a Japanese beetle eradication project in South Central Washington since 2022, after extensive trapping efforts in 2021 found almost 24,000 beetles in Grandview and the surrounding area. WSDA saw a decline in beetle detections in 2023, but the numbers rebounded to almost 25,000 in 2024 and climbed to over 70,000 in 2025. Beetles were found in Grandview, Sunnyside, Mabton, Wapato, Pasco, Kennewick, and near SeaTac.

Although beetle trapping is underway, WSDA is still applying a reduced-risk insecticide to properties in the treatment areas that opt in. “Property owners in the treatment area can still sign up for free treatments. If your property isn’t treated, it becomes a potential breeding ground for beetles in your neighborhood,” Sven Spichiger, Pest Program manager, said. “Our only hope of eradicating this beetle is for people in treatment areas to give consent and sign up for treatments.”

The Pest Program is also conducting high-density trapping for spongy moths near Lake Youngs and Lakewood, where WSDA conducted spongy moth treatments last month, in addition to its usual survey efforts. “Residents in areas where we treated for spongy moths this year can expect to see lots of traps in their neighborhoods this summer, which help confirm that the spongy moth treatments were successful,” Spichiger said. “Whether in a treatment area or part of our statewide detection effort, every trap is critical to our ability to accurately detect spongy moths. If you see a trap, please don’t disturb it.”

Spongy moth and Japanese beetle are just two of the pests that WSDA’s Pest Program monitors for every year. Other major pests WSDA will be looking for this year include apple maggots, grape and stone fruit pests, wood-boring insects, spotted lanternfly, and yellow-legged hornets.

All WSDA Pest Program survey staff wear WSDA-issued safety vests and have WSDA identification. Traps are placed on public lands when possible, but may need to be placed on private lands, which state law permits, to ensure systematic pest detection grids.

WSDA’s traps are labeled for easy identification. If a trap has fallen or needs to be moved, please note the number written on the trap and contact the WSDA Pest Program at pest@agr.wa.gov or 1-800-443-6684.