State begins annual treatments to eradicate invasive beetle

OLYMPIA, WA – Annual Japanese beetle (Popillia japonica) treatments to eradicate the invasive Japanese beetle are starting this week. The Washington State Department of Agriculture (WSDA) is conducting Japanese beetle treatments in Grandview, Sunnyside, Mabton, Prosser, Wapato, Pasco, Kennewick and SeaTac and surrounding areas in King County as part of a multiyear eradication effort. 

Treatments begin in the Tri-Cities area this week. The treatments will begin in Yakima and Benton counties next week and in King County on April 13. The start of treatments is based on when the Japanese beetle larvae are anticipated to resume actively feeding in the soil. The weather also impacts when treatments occur, as the treatments cannot take place when it is too rainy or windy. 

Treatment consents urgently needed

Less than half of all treatment area residents have responded to WSDA’s requests for consent to treat their property. 

“Our state’s beetle eradication success or failure hinges on getting access to treat properties,” Sven Spichiger, WSDA’s Pest Program manager, said. “Untreated properties become a haven for beetles where they can thrive and multiply. To succeed, everyone in each community threatened by Japanese beetle needs to come together and ensure that all properties are treated.” 

Treatment consists of applying a reduced-risk insecticide to the ground. The insecticide is not considered a safety risk for humans, pets, or wildlife such as birds, fish, or honey bees. WSDA has contracted with licensed pesticide applicators to conduct the treatments. Treatments are free for properties within WSDA’s designated treatment areas. 

Treatment area residents who have not yet provided consent to have their property treated are asked to give consent as soon as possible. Residents can visit agr.wa.gov/beetles to see if they are in a treatment area and provide consent online. For additional assistance, those in the treatment areas can contact the WSDA Pest Program at pest@agr.wa.gov or 1-800-443-6684. Assistance is available in both English and Spanish. 

Preparing yards for treatment

Email or text notifications will be sent to residents prior to treatment. Residents do not need to be on site for treatments, but are asked to prepare their yards so that the treatments are not delayed: 

• Clear 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 as a precaution. Once it is dry, entrance is permitted without any further restriction, but residents should wait at least one day before mowing their lawns.

Background

Japanese beetles were initially detected in Grandview and Sunnyside in 2020 when a total of three beetles were trapped in the area. Since then, thousands of beetles have been trapped in multiple counties. WSDA conducted the first treatments for Japanese beetle in 2022 and expects eradication to take multiple years.  

Adult Japanese beetles 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 as adults as summer approaches.

The beetles are pests of more than 300 types of plants, including lawns, roses, grapes, hops and more.

Visit agr.wa.gov/beetles to learn more about the beetle and WSDA’s eradication project. 
 

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