Japanese beetle treatments coming to Sunnyside after pest found in force

The Washington State Department of Agriculture (WSDA) will begin treating properties in Sunnyside for Japanese beetles after the agriculture-damaging pests were found in the city in 2023.

“Japanese beetle is a scarab beetle, it’s a highly invasive species,” said Camilo Acosta, WSDA Japanese beetle eradication coordinator. “We caught 18 beetles in Sunnyside.”

Acosta has led a region-wide effort to stem the beetle invasion. Japanese beetles can harm crops, including grapes and hops, but that’s not where the problem stops. They can also eat lawn roots and damage gardens.

WSDA efforts have centered around Grandview, where tens of thousands of beetles have been found. Now, Acosta said, state officials are expanding the treatment area to Sunnyside and Mabton.

“In Sunnyside in particular, we’re looking at just over 3,600 properties,” Acosta said.

WSDA has sent letters to residents asking to treat their yards with Acelepryn, an insecticide, between April and June. It’s a low-risk insecticide, Acosta said, with no documented health effects in pets or people. The treatment is free and will only happen with the consent of property owners, he added.

Acosta said it takes several years of treatments to see effects due to the beetle’s life cycle, but there have been documented successes. In Grandview, there were 5,000 fewer beetles trapped this year after two years of treatment, Acosta said.

“We will still see beetles this year with the treatments. There’s a one-year lag,” Acosta said. “We’re going to treat, but we’re not going to kill all the beetles this year.”

WSDA is also working on a quarantine for yard debris. Beetles can be transported in yard trimmings and debris, Acosta said, so it’s important to make sure yard debris is disposed of properly. He said yard debris had to be quarantined between May and October, the adult beetle’s flight season, to make sure the beetles did not spread.

Acosta said a second round of letters would be sent out to residents for yard treatment. Residents could also contact WSDA by email at pestprogram@agr.wa.gov or phone at 1-800-443-6684. To sign up online for treatment, residents need to give a five-digit pin. For more information, visit agr.wa.gov/beetle.