GRANDVIEW, Yakima County — Two years ago, Grandview resident and gardening enthusiast Melodie Smith noticed some shiny, unusual-looking bugs taking an unwelcome interest in her roses.
She took photos of the insects, showed them to an entomologist friend at Yakima Valley College’s Grandview campus, and soon realized her beloved roses were being eaten by Japanese beetles, an invasive species that has caused extensive plant damage in the Midwest and eastern U.S.
“They start with the roses. Then they go for the grapevines and they eat up all the vines,” Smith recalled. “Our neighbor planted corn stalks, and they went after those. That’s when I realized we’ve got a real problem on our hands.”
The latest effort to solve that problem has begun this month, as the Senske lawn care company has begun spraying an insecticide to kill the beetles’ larvae in a 3,100-acre area around Grandview, said Camilo Acosta, Japanese beetle eradication coordinator for the Washington State Department of Agriculture.
“Right now we’re looking at 4,200 properties within the treatment area — most of Grandview and some adjacent areas,” Acosta said Monday. “This treatment is targeting the grubs that will be hatching this summer … The larvae will hatch underground and eat the roots of this grass, which has been treated with the insecticide.
“Beginning in another four to five weeks, we’ll do another treatment that targets the adults who are flying around,” he added.
Drastic measures for a growing problem
Smith was one of the first to notice the beetles, finding them on her roses in 2020. That prompted WSDA to deploy 1,900 traps across the state in 2021 to gauge the extent of the problem.
About 900 traps were set in a 49-square-mile area around Grandview, and those traps caught 24,048 beetles, Acosta said. Almost all of the beetles found in Washington were concentrated in this mostly residential area, prompting WSDA officials to begin their eradication plan this year.
First found in New Jersey in 1916, Japanese beetles eat more than 300 types of plants, including roses, grapes and hops. The adult beetles damage plants by skeletonizing the leaves. Adults also feed on buds, flowers and fruit on the plants and are frequently intercepted on fruit transported from the eastern U.S.
The Japanese beetle larvae are found in soil associated with the roots of host plants. They are common under turf and sod, and can be moved in potted plants, WSDA media relations coordinator Amber Betts said. She noted beetles can lay 60-100 eggs in their lifetime, meaning there will likely be many more than 24,000 beetles in southeast Yakima County this year.
The beetles are considered a threat to the high-value agricultural industry in the Yakima Valley. The state also is working to implement a 49-square mile quarantine area with Grandview at its center.
The spraying begins
After numerous education efforts both online and in person for the past six months, WSDA officials sought permission from Grandview property owners to treat their yards with the Acelepryn G insecticide, and more than 1,900 already have agreed, Acosta said.
Letters were sent to property owners in late March, and both paper and online permission forms continue to be returned as residents see the insecticide begin to be applied in their neighborhood, he added.
“We’re only treating properties where we have permission, but as we go out and start the treatments, people are signing up on the spot,” Acosta said Monday, as Senske employee Jon Doney sprayed the lawn around Smith’s home in central Grandview.
“It’s been a lengthy process to get access and to treat all these properties, but the more people who agree to let us spray, the more effective the program will be.”
Mallory Little, a toxicologist with the Washington state Department of Health, said during a public forum in February that the insecticide’s active ingredient, chlorantraniliprole, has been used against Japanese beetles between 2010 and 2021 in several Western states, and no illnesses were reported in humans or animals.
As a precaution, Little urged homeowners whose yards will be sprayed to stay inside for four hours afterward to allow the droplets to dry. Pet dishes and water bowls should be moved inside before the insecticide is applied, and any skin or clothing that comes in contact with the insecticide should be washed with soap and water.
This is the largest, but not the first, application of insecticide to eradicate Japanese beetles in a Western U.S. community, Acosta said.
An area near Boise, Idaho, was treated beginning in 2013 and successfully eliminated the beetles after a five-year process, WSDA biologists said earlier this year.
Another area northwest of Portland has been treated with insecticide for the past four years and has seen the number of pests decrease.
Surveys, trapping and quarantine efforts also will continue in the Grandview area as the WSDA embarks on a four- to five-year process to eliminate the beetles and the threat they pose to the region’s agriculture.
“Our goal is not just to contain them, but eradication,” Acosta said. “We want zero Japanese beetles in the Yakima Valley.”
More information is available at the WSDA’s Japanese beetles website, agr.wa.gov/beetles.