Japanese beetles spotted in Grandview for the first time in 2022

Japanese Beetles Grandview
Courtesy: Washington State Department of Agriculture

GRANDVIEW, Wash. — Researchers have now confirmed sightings of invasive Japanese beetle adults and larvae in Grandview for the first time this year and are working on eradicating as many as possible to keep the population from growing.

Japanese beetles eat more than 300 kinds of plants, including some of Yakima County’s crucial agricultural exports like grapes, hops and apples — and can lay about 60 eggs each year.

“That means its population is free to grow unchecked,” Betts said. “And that it’s going to be more difficult and more expensive to control and keep out of our products.”

For the past month, Washington State Department of Agriculture researchers have been treating affected properties in residential areas before the pests can spread to crops, targeting about 2,000 acres in Grandview and surrounding areas of Yakima and Benton counties.

“Now we’re going to be focusing our efforts on monitoring the traps, figuring out where the beetles are at and then also working on getting that quarantine rule adopted,” Betts said.

Betts said the first two beetles of the year were discovered by researchers Tuesday in one of the 2,229 traps deployed throughout the Grandview area. Last year, researchers were able to trap more than 24,000.

“The adult emergence is about late June, so we’re just starting to see that,” Betts said. “And because it was a cooler atmosphere in June, we’ll probably start seeing the biggest emergence in a couple of weeks.”

Betts said they have seen grubs already this summer, with the first being discovered June 13 by a resident in Grandview who was weeding and found grubs in her garden bed. They’re removing the larvae from her garden and have placed traps on her property to catch any adults.

One of the best things Grandview residents can do to help prevent the Japanese beetles from spreading, Betts said, is to keep their “green waste” on their property for the time being.

Betts said that includes items like soil, dirt, fill, potted plants, outdoor plants and waste or debris from yards or gardens.

“What we really don’t want to see as people take their plant material outside of the infestation area and then further spread the population of those beetles,” Betts said.

Betts said people should keep their green waste on their property for a couple of weeks and then WSDA will set up a spot for them to dump it and it will be taken care of in a way that will get rid of any stowaway beetles.

“Throughout July, we’ll be monitoring the traps and seeing where the most activity is and then we’ll be doing additional treatments in those areas,” Betts said.

Researchers ask anyone who suspects they’ve seen a Japanese beetle to report it: take a picture, note the location and provide that information through WSDA’s online reporting form, by emailing PestProgram@agr.wa.gov or by calling 1-800-443-6684.