Japanese beetle infestation threatens Washington agriculture, gardens
YAKIMA COUNTY, Wash. - The invasive Japanese beetle is wreaking havoc on Washington’s agriculture and gardens, and state officials warn that the fight to eradicate the pest could take over a decade.
The beetle, first detected in the state in 2020, has rapidly multiplied, particularly in Benton, Franklin, and Yakima counties.
The Japanese beetle, known for its metallic green body and copper-colored wings, feeds on more than 300 plant species, including roses, grapes, hops and corn.
"It skeletonizes leaves and buds of flowers and leaves a mess," said Cassie Cichorz with the Washington State Department of Agriculture (WSDA).
Washington’s experience with the pest dates back to the 1990s when small populations were occasionally found near Sea-Tac Airport. These detections did not indicate established populations until 2020, when three beetles were found in Sunnyside and Grandview. By 2021, the population had exploded to over 24,000 beetles, according to Camilo Acosta, the Japanese beetle eradication coordinator with the WSDA.
The Japanese beetle doesn’t bite or sting, but its damage to crops and gardens affects everyone. From the price of vegetables at grocery stores to the availability of flowers for events like weddings, the beetle’s presence could touch many aspects of daily life.
The Yakima Valley, which produces about 75% of the nation’s hops, is particularly vulnerable. Acosta emphasized that hops, grapes, and corn are among the crops most at risk. Beyond agriculture, the beetle’s reach extends to backyard gardens.
"I've seen them underground eating cilantro, pineapples, potatoes," Acosta said.
Invasive Japanese beetles found in Yakima County
The Washington State Department of Agriculture (WSDA) says the first Japanese beetle of the year was spotted in Yakima County, and the time to take action against these invasive insects is now.
Oregon’s estimate from over a decade ago suggested a $45.5 million economic loss if the beetles were not eradicated—a figure Washington officials hope to avoid.
The WSDA has implemented a comprehensive eradication strategy, including the deployment of thousands of traps and the treatment of affected properties. Last year, 26,709 beetles were captured. Despite these efforts, the pest continues to spread, aided by human activities such as hitching rides on cars and trains.
Approximately 17,600 properties in Benton, Yakima, and Franklin counties are now slated for treatment with insecticide. However, the process is slowed by the need for property owner consent.
"Unfortunately, we only receive about 50% of responses back and about 50% has gone with no response so this is the hardest part about the program," Cichorz said.
WSDA’s eradication strategy includes free pesticide treatments targeting turf grass and other host plants.
The pesticide used, Acelepryn, has been deemed safe for humans, pets, and wildlife by the Department of Health. Treatments will not target vegetable gardens, focusing instead on turf grass and ornamental plants where the beetle thrives.
The treatment program is scheduled to begin on March 31, targeting beetle larvae as they emerge from winter dormancy, and could take at least a decade to fully eradicate the Japanese beetle. Acosta and his team remain committed, recognizing the urgency of the situation. "It is quite frightening, quite alarming, how they can spread. And that's why we're taking this as seriously as we are," Acosta said.
Residents are encouraged to check their mail for notifications from the WSDA and grant permission for treatment. You can sign up online.
BEST OF FOX 13 SEATTLE
New 2025 laws that are now in effect in WA
Orca Tahlequah seen pushing second dead calf in WA waters
WA skiers demand action as 'rampant' thefts plague Stevens Pass
Here's when you'll need REAL ID to go through US airport security
New restaurants coming to Seattle in 2025
To get the best local news, weather and sports in Seattle for free, sign up for the daily FOX Seattle Newsletter.
Download the free FOX LOCAL app for mobile in the Apple App Store or Google Play Store for live Seattle news, top stories, weather updates and more local and national coverage, plus 24/7 streaming coverage from across the nation.