Looking to gain a handle on the state’s largest-ever Japanese beetle outbreak, the Oregon Department of Agriculture has proposed doubling its treatment area around the Cedar Mill and Bethany neighborhoods in unincorporated Washington County.
ODA will host a pair of public meetings in February to discuss the effort, which would include applying a granular insecticide over 1,900 acres beginning in April and finishing at the end of May.
The Japanese beetle is a voracious pest that feeds on a variety of plants and crops, including grapes, berries and orchard fruit. ODA estimates the beetles would cost Oregon agriculture $43 million per year if they became established and dispersed throughout the state.
Clint Burfitt, insect pest program manager for the department, said Japanese beetles have historically arrived in Oregon from infected states via air cargo at Portland International Airport. That is where officials concentrated most of their attention.
However, with budget cuts to the Japanese beetle monitoring program, Burfitt said they left their flank unguarded. In 2016, ODA detected 369 beetles in Cedar Mill and Bethany, adjacent to Northwest Portland. Burfitt does not know where exactly the beetles came from, but suspects it may have been from potted plants brought in by a homeowner.
It was, at the time, the most beetles found during a single field season in Oregon.
In 2017, ODA kicked off a five-year project to wipe out the beetles, treating 2,121 homes on roughly 1,000 acres. Yard debris was quarantined and disposed of separately to prevent the insects from getting loose.
Still, the department detected more than 23,000 beetles later that summer, including 750 — about 3 percent — outside the treatment area.
“We were anticipating thousands of beetles, not tens of thousands of beetles,” Burfitt said.
Increased monitoring statewide also led to the discovery of 11 Japanese beetles 175 miles south in Douglas County, including Oakland and Green. Another 11 beetles were found at the Portland airport and five at Swan Island in Portland.
Heading into year two of the eradication project, ODA would expand treatment to 1,900 acres around Cedar Mill and Bethany, 150 acres at the Portland airport and 34 acres in Douglas County. Officials would place traps at Swan Island, but are not planning any treatment of the area.
It will take ODA about six weeks to apply the product known as Acelepryn on all grass and ornamental plant beds in the treatment area. Applications are free for property owners, though they need to give permission for ODA to enter their properties. The department is hoping for 100 percent cooperation.
Meetings about the proposed 2018 project will be Tuesday, Feb. 6, from 5:30 to 7 p.m. at Sunset High School, 13840 NW Cornell Road, Portland, and Tuesday, Feb. 13, from 9:30 a.m. to 12:30 p.m. at the Leedy Grange, 835 NW Saltzman Road, Portland. Experts including ODA staff, public health officials and partner agencies will be on hand to answer questions and address concerns.
A final decision on the 2018 project is expected by March.