Courtesy Washington State Department of Agriculture
The Washington State Department of Agriculture tentatively plans to aerial spray an insecticide over two westside counties next spring to kill gypsy moth larvae, responding to the largest outbreak of the leaf-eating pest in more than 20 years.
WSDA has trapped 117 European gypsy moths since July, the most since 1995. Most of the catches were in the neighboring cities of Puyallup and Graham in Pierce County and Bremerton and Silverdale in Kitsap County.
The department has not proposed a detailed plan, but has started to line up state and federal funding to spray a total of approximately 1,300 acres.
Washington and other Western states take a hard-line against gypsy moths. The moths are entrenched in 19 Eastern states and reputed by federal and state agricultural officials to be the most destructive forest insect ever introduced in North America.
If established in Washington, gypsy moths would be especially threatening to the timber, nursery and Christmas tree industries, according to WSDA. The moths spread by laying egg masses on outdoor belongings transported across the country. WSDA has sprayed for gypsy moths numerous times since 1979, but did not this year.
The Oregon Department of Agriculture also did not spray this year and won’t next spring, department spokesman Bruce Pokarney said Monday.
The department trapped 10 European gypsy moths this year, including five in Benton County, in or near Corvallis. “We’ll have to keep an eye on that next year,” he said. “We’ll put more traps out.”
The department also trapped two gypsy moths south of Eugene and three at scattered sites in Portland. None of the three were caught in the 8,800 acres in Portland the department sprayed in 2016. “That’s the best news of all,” Pokarney said.
The gypsy moth trapping season was more lively in Washington. In a first for Washington, WSDA found about 100 gypsy moths laying eggs in a Puyallup neighborhood. Female gypsy moths can’t fly, so only male gypsy moths are snared in the traps.
WSDA said the discovery likely curbed a serious outbreak. Still, the department has put in a budget request to the governor’s office for $230,000 to spray and to put out traps to see whether the operation worked. The department also hopes to receive $715,000 from the USDA.
WSDA trapped 87 gypsy moths in Pierce County and 17 in Kitsap County. Gypsy moths also were caught in Clark, King, Island and Whatcom counties.
Neither Washington nor Oregon trapped an Asian gypsy moth this year. Female Asian gypsy moths fly and are considered a greater danger to spread than European gypsy moths.
Washington would spray Bacillus thuringiensis kustaki, a biological pesticide approved for organic use.