OLYMPIA — Annual treatments against invasive Japanese beetles began Monday in South Central Washington, according to an announcement from the Washington State Department of Agriculture. WSDA is conducting treatments in Grandview, Sunnyside, Mabton, Prosser, Wapato and Pasco as part of a multi-year eradication effort.

“Our efforts are starting to work,” Japanese beetle eradication coordinator Camilo Acosta said. “But the (more) people who sign up for treatments, the more successful we’ll be at getting rid of this pest.”

Treatments on large public properties are scheduled to begin early this week and crews will follow with treatments at private residences where residents and property owners have given consent for treatment. The statement said WSDA encourages property owners who have land in the treatment area to provide consent as soon as possible. 

According to the statement, Japanese beetles were initially detected in Grandview and Sunnyside in 2021. The following year, WSDA trapped over 24,000 beetles in the same area. Numbers dropped to 19,000 beetles in 2023. The beetles are a pest to more than 300 types of crops, including lawns, roses, grapes and hops, the statement said.

WSDA is hoping to treat 11,000 properties in southeastern Washington, the announcement said. A certified pesticide applicator contractor will conduct the treatments, and the product being used is an insecticide called Acelepryn. According to the Washington State Department of Health, the pesticide poses a low risk to humans, pets and birds, the statement said.

Notices will be sent to residents before treatments occur. Even for those who have consented to have their property treated, there are steps they need to take to enable WSDA to treat their yard, according to the announcement:

• Clear the lawn of all items.

• Keep pets inside or isolated from lawns and shrubs.

• Keep gates unlocked or open as backyards also need to be treated.

• Ideally, mow the lawn shortly before treatment.

Once the property is treated, both people and pets should stay out of treated areas until the product is dry. Once it is dry, entrance is permitted without any further restriction.

Consent can be given at agr.wa.gov/beetles. For additional assistance in giving consent, property owners can contact the Pest Program at pest@agr.wa.gov or 1-800-443-6684. Assistance is available in both English and Spanish, according to the announcement.