Infestation of highly destructive bugs spreading in Tri-Cities. Can they be stopped?

More highly destructive Japanese beetles have been found in Pasco this year, spreading beyond the area where they were found last year.

Thirty-four have been found this year in Pasco, with only a few of them in the area that was of most concern last year.

“This is obviously a huge issue, and we’re seeing this infestation unfold in real time,” said Camilo Acosta, Japanese beetle eradication project coordinator for the Washington state Department of Agriculture, Wednesday at the Franklin County Commission meeting.

Around July 4, Japanese beetles were caught in three traps near North Fourth Avenue. Two of the traps were at Volunteer Park and the third trap was at Sylvester Park, Acosta told the Tri-City Herald.

Japanese beetles also have been trapped this year near the Columbia River just east of the blue bridge.

The nonnative beetles feed on more than 300 plants, and can devastate grape crops, strip roses and other garden plants of their leaves, and damage grass at homes, parks and golf courses.

In a worst-case scenario, farmers could be prohibited from sending agricultural products out of areas with Japanese beetles infestations.

Japanese beetles have been found so far in Washington along about 65 miles of the Interstate 82 corridor, mostly in Yakima County and the western edge of Benton County.

Officials want to avoid a repeat of what happened in Yakima County. There a 74-square-mile quarantine area has been established where yard debris, flowers, plants, topsoil and potted plants cannot be removed.

Two beetles were caught in Grandview and Sunnyside in 2020. Mass trapping followed, finding as many as 24,000 a year, all but a handful in a gradually expanding area of Yakima County and just over the county line in Benton County.

Last year five Japanese beetles were found in Pasco , including four in a roughly square mile area near the U.S. Post Office on Court Street and at different Henry Street addresses in the Road 36 area.

The Washington state Department of Agriculture considered making that square mile a quarantine area with a dedicated drop site for yard debris within it, but then decided to initially focus on spraying pesticide in the area. Finding a drop site in the mostly residential area proved difficult.

The square mile of most concern last year extended from near Interstate 182 south to the Columbia River and from near Road 46 east to almost Road 30 covering 1,058 properties

Pasco lawns sprayed

Owners were contacted for permission to spray the insecticide Acelepryn on their property in the spring to eradicate the larvae of the Japanese beetles .

The program achieved about 55% participation after state employees sent letters and went door to door. That was higher than has been seen elsewhere for the first year of the program and the highest of any city requiring treatment this year, Acosta said.

The Washington Department of Agriculture expected to trap more Japanese beetles in Pasco this year after finding the beetles last year too late for larvae treatment with insecticide.

It may still treat the grass at Volunteer Park this summer, since it has such a large grassy area, even though the insecticide will not be as effective as if it were used in the spring.

Seven Japanese beetles have been found this year at the park across North Fourth Avenue from the Franklin County Courthouse.

The Washington state Department of Agriculture also is planning a new program to treat host plants for the adult Japanese beetles in Pasco with insecticide in areas where more than two Japanese beetles have been trapped.

Fruit trees and vegetable gardens would not be treated, but Japanese maples, poplar, birch and elm trees could be, Acosta said.

The Department of Agriculture also could revisit the idea of a plant, soil and yard debris quarantine for parts of Pasco next year.

So far the infestation has remained on the Pasco side of the river, although one Japanese beetle was found in the Duportail Street area of south Richland in 2022.

When extensive trapping turned up no other Japanese beetles in the area, officials suspected it might have been brought in on a plant at a nearby garden center.

Help eradicate Japanese beetles

The Washington state Department of Agriculture is asking for residents of the greater Tri-Cities area to keep an eye out in their flower and vegetable gardens and their trees for unusual, metallic green and brown beetles that have little tufts of white hair on their sides.

A find of Japanese beetles can be reported at bit.ly/ReportBeetlesWA or by email to PestProgram@agr.wa.gov with contact information, the location, date, photographs of the beetles and the number seen.

Or residents can call 800-443-6684.

After taking a photo, make sure the beetles are dead before discarding them.

Residents also can help by purchasing traps sold at home and garden stores and using then on their property from spring through fall, according to the state.

The traps allow any beetles caught to be killed and help the state track the infestation.

Adult beetles can hitchhike on vehicles and on items stored outdoors.

When adult beetles are flying from late spring through October, those who live in or visit areas with infestations should take a few seconds to ensure they are not giving a free ride to beetles when they leave the area.

This can be as simple as checking the back of your pickup truck, according to the Department of Agriculture.