After more than 15 years of being gypsy moth free, the Washington State Department of Agriculture has found what it calls “the worst forest pest insect ever to enter the United States” in Washington. Now, officials are moving quickly to stop the gypsy moth before it can establish itself in the Pacific Northwest.
Last year, the WSDA put out 19,000 traps around Western Washington and caught 42 gypsy moths. Ten Asian gypsy moths were found in the state. One was found in Vancouver and two others were found in Portland.
“What we don’t normally find is Asian gypsy moths; 10 is most we ever caught. But it’s way worse because females can fly — so populations can spread much more rapidly — whereas the European females don’t,” said Karla Salp, community outreach and environmental education specialist with WSDA.
European and Asian gypsy moths have wreaked havoc on forests in 19 Northeastern and Midwestern states. The bugs spread quickly and have extensively damaged hundreds of thousands of acres of forests, which, in turn, harms wildlife habitat and stream quality. Once a population is established it’s practically impossible to eradicate them.
“On years where (the gypsy moth) has big infestations, it can explode,” Salp said. “In one year, it damaged 13 million acres of trees.”
The European gypsy moth eats deciduous trees. The Asian variety eats evergreens. An established population of either one would be disastrous for the evergreen forests and apple orchards of Washington.
To combat the moths, Washington and Oregon’s departments of agriculture are planning to have areas where the moths were found sprayed with the bacterial insecticide bacillus thuringiensis kurstaki, or BTK, this spring.
“It’s been used for decades, and there’s been a lot of research demonstrated there’s no health impact to humans, fish, pets or ladybugs,” Salp said. “It only affects caterpillars.”
Hector Castro, a spokesman for WSDA, said that as a rule, when one Asian gypsy moth is found in a 1-square mile area, that area is treated three to five times over the course of a few weeks.
The Vancouver treatments will be around the Port of Vancouver and into parts of Fruit Valley.
Officials believe the moths came over on cargo ships unloaded at the ports in Tacoma and Seattle. Four other Asian gypsy moths were found at the Port of Tacoma, and one was found in Gig Harbor.
“There is a system through federal government to monitor the ships and search for gyps, but it’s not necessarily possible to detect every single egg mass in every ship,” Salp said.
WSDA will host an open house about the moths and the treatment from 5:30 to 7:30 p.m. Tuesday at the Vancouver Public Library located at 901 C St.
Asian gypsy moths were first found in Washington state in 1991, and officials worked for the next eight years to eradicate them. From 2000 through 2014, there were none found in the state.
