Agriculture officials in Washington state have begun the latest in their annual treatments against the Japanese beetle, a pest harmful to numerous crops.

The state Department of Agriculture on April 1 began conducting treatments in Grandview, Sunnyside, Mabton, Prosser, Wapato and Pasco as part of a multiyear eradication effort.

The treatments started less than a month after the state expanded the boundaries of a quarantine for the pest in central Washington based on trapping data from the 2023 season.

Treatments started on large public properties and will continue at private residences where landowners give consent, which is urged as soon as possible.

WSDA is hoping to treat 11,000 properties in southeastern Washington. A certified pesticide applicator contractor will conduct the treatments on behalf of WSDA. The product being used for the treatments – an insecticide called Acelepryn, is a reduced-risk pesticide that according to the Washington State Department of Health poses low risk to humans, pets and birds.

Japanese beetles were initially detected in Grandview and Sunnyside in 2021 when a total of three beetles were trapped in the area. The following year, WSDA trapped over 24,000 beetles in the same area. Numbers dropped to 19,000 beetles in 2023. 

Related:Wash. expands beetle quarantine boundaries

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

Japanese beetle adults are metallic green and brown and have little tufts of white hair on their sides. They emerge – usually from lawns or in other soil – in the spring and feed throughout the summer. From fall to spring the grubs (larvae) overwinter in the soil and slowly develop into mature adults ready to emerge again in the spring.

The beetles are a pest of more than 300 types of crops, including lawns, roses, grapes, hops and more.

For additional assistance giving consent, property owners can contact the Pest Program at [email protected] or 1-800-443-6684. Assistance is available in both English and Spanish.

Source: Washington State Department of Agriculture