The Washington state Department of Agriculture is expanding eight-fold the area of private and public land in the Tri-Cities it wants to spray pesticide to fight highly destructive Japanese beetles.
What was one square mile treated in Pasco last spring, will expand to eight square miles, including a slice of Columbia Park on the south side of the Columbia River in Kennewick this year.
It will be the first time treatment has been done in Kennewick by the state to kill Japanese beetle larvae or grubs in the soil before they emerge as adults.
In 2023, five Japanese beetles were found in Pasco, but the next year 408 were found in Pasco and one in a trap across the Columbia River in Kennewick near Hawthorne Elementary School.
Statewide Japanese beetles caught in Department of Agriculture traps increased from 19,544 in 2023 to 26,700 last year.
Most were in caught in the Lower Yakima Valley, with 24,700 found in Sunnyside, Grandview, Mabton and the far west side of Benton County. The Japanese beetles also have been found in Prosser, since the infestation started with three beetles in Grandview in 2020.
Japanese beetles feed on more than 300 plants, and can devastate grape crops, strip roses and other garden plants of their leaves, and damage turf at homes, parks and golf courses.
Adult Japanese beetles are up to a half inch long and have a metallic green head and thorax and iridescent copper wing covers. White C-shaped larvae with a tan head and visible legs may be seen during the spring.
State Department of Agriculture officials said in November that trapping alone is not enough to eradicate Japanese beetles from the state.
Beetle treatments lagging
So far spring pesticide treatments have been voluntary and property owners must give consent each year to have their properties treated.
But only about half of property owners in areas of concern gave permission to have their land treated last year.
“So far the level of community participation has only been enough to slow, but not stop or eradicate Japanese beetles from our state,” said Sven Spichiger, pest program manager for the Department of Agriculture, in a statement. “If we aren’t allowed to treat most of the properties in the infested areas, it is only a matter of time before it is too late to eradicate.”
Then homeowners, gardeners and farmers will be left with the responsibility and expense of not only managing the pest, but the burden of following permanent quarantine regulations as well, he said.
Parts of the Lower Yakima Valley already are under a Japanese beetle quarantine. Residents are not allowed to remove soil or sod or plants not free from soil, such as fruit trees and potted plants, from the quarantine area year round.
The removal of plants and plant cuttings, roots, grass clippings, cut flowers, among other vegetation that could harbor Japanese beetles, is prohibited in the area May 15 to Oct. 15, the season when adult beetles live. Instead, they must be taken by landowners to special disposal areas.
In states that have permanent infestations of the beetles, farmers and plant nurseries are subject to expensive and restrictive quarantines to move their products, as well as increased pesticide costs to manage the beetle, according to the Washington state Department of Agriculture.
Residents must deal with the pest in their lawns and gardens as well, either increasing pesticide use or manually removing the beetles — some even using vacuums because of the sheer number of beetles, the agency said. Visitors and tourists must also deal with the beetles being a nuisance flying into them.
Pasco, Kennewick treatment areas
The Department of Agriculture is asking permission from Tri-Cities landowners this year to treat land from North Road 64 east to around North First Avenue in Pasco.
The southern edge of treatment for Pasco would be the Columbia River or East Ainsworth Avenue north to West Livingston Road, including part of Columbia Basin College north of Interstate 182.
In Kennewick, the area to be treated would be in Columbia Park west of the blue bridge along the river for almost a mile and would also include a small amount of private land south of Highway 240.
Treatment is done with the insecticide Acelepryn, which kills Japanese beetles and certain other pests in their grub or larval stage in the soil. It is not considered a health risk for people, pets, wildlife or insects, such as bees, that don’t go through a larval state in the soil.
About 17,600 property owners in Yakima, Benton and Franklin county treatment areas have been mailed letters with a consent form and a PIN number.
If you are in a treatment area and need a form to permit spraying, they are available at the Pasco City Hall, plus additional city halls in the Lower Yakima Valley. To sign up online, go to agr.wa.gov/beetles and scroll down to the “sign up now” box.
