Renton sparked attention from state entomologists, when it became one of the first cities to catch a gypsy moth this year.
Though Renton isn’t historically a hot spot for the pest, the Washington state Department of Agriculture responded by adding about 100 traps to the about 22 that were already placed, managing entomologist Jim Marra said.
In Renton trappers are concentrating on the intersection of Southwest 27th Street and East Valley Highway in south Renton.
The triangular traps are be set up from June to September, with August expected to be the major month for catching the moths.
The roughly 2 1/2-inch insects, native of Asia and Europe, feed on about 500 species of trees and plants, including conifers.
The caterpillars do most of the damage, destroying wildlife habitats and harming agriculture and timber production.
“They’re extremely aggressive to foliage and trees,” Marra said. “They are capable of defoliating entire forests.”
Trappers set up about 5,400 traps in King County and 24,000 in Washington state, according to a press release.
The traps are fairly simple, luring males in with the female pheromone, Marra said. “The males fly into the trap thinking they’ll find a mate and then they get trapped in the viscous sticky of the trap.”
If a moth is found, researchers put up a four-mile grid with 25 traps per square mile. About 30 trappers check the boxes about every two to three weeks.
A successful grid lets entomologists know if spraying is necessary and where to focus.
The number of moths the state catches each year varies with about 21 last year. The largest number caught was in 1983 with 1,315.
Though Washington’s 35-year-old project has successfully staved off a permanent moth population, about 19 states in the United States have established gypsy moth populations, Marra said.
Those moving to Washington from an infested state are required to complete a self-inspection check sheet before leaving, Marra said. For more information about the gypsy moth, contact the state Department of Agriculture.
