After setting 34,000 traps around the state this summer to catch the much-loathed European and Asian gypsy moths, the Washington State Department of Agriculture has reportedly caught 25 of the voracious bugs, down from the 42 caught in 2015.
One European gypsy moth of the 25 trapped this summer was found in Hockinson. None of the moths found were caught in areas that were sprayed for gypsy moths earlier this year. Statewide, no Asian gypsy moths were found, after last year’s record catch of 10.
“It’s a big relief, no Asian moths were caught,” said Karla Salp, community outreach and environmental education specialist with WSDA.
However, department officials said two to three years of trapping after a spray treatment are required before WSDA determines the success of a treatment.
“While it is too early to declare the spring treatments a success, this year’s trapping results are very encouraging,” Jim Marra, WSDA’s Pest Program Manager and leader of the gypsy moth program, said in a news release.
Vancouver had a high concentration of the traps this summer because one Asian gypsy moth — the more problematic of the two — was found at the Port of Vancouver in 2015.
The Asian variety is particularly dangerous because, unlike the Europeans, both male and females can fly, so their populations can get out of hand very quickly.
This spring, the Washington and Oregon’s departments of agriculture sprayed where the moths had been found. Officials sprayed with the bacterial insecticide bacillus thuringiensis kurstaki, or BTK, a pesticide approved for organic agriculture to kill gypsy moth caterpillars. Locally, that included the Port of Vancouver and part of the Fruit Valley neighborhood.
According to Salp, the moths eat more than 500 varieties of trees and shrubs, which enables them to spread quickly and broadly. European and Asian gypsy moths have wreaked havoc on forests in 20 Northeastern and Midwestern states and Washington, D.C. Their infestations have extensively damaged hundreds of thousands of acres of forests; so vast are the defoliated swaths, they are visible from space.
An established population of either the Asian or European variety would be disastrous for the evergreen forests and apple orchards of Washington.
Salp also said it’s not a foregone conclusion, but if surveyors find no new egg masses in the areas where the moths were trapped, then the state likely won’t have to do any new gypsy moth spray treatments in 2017.
WSDA officials said the damage moths do to trees has a ripple effect, impacting wildlife habitat and stream quality. Once a population is established, it’s practically impossible to eradicate them, officials said.
