The annual push to control a destroyer of forests has started, with crews hanging 16,000 traps in Washington, including in Whatcom County.
The tent-shaped cardboard traps are used to catch male European and Asian gypsy moths, which are lured by the scent of what they think is a female moth.
In their caterpillar forms, the non-native pests are voracious eaters of more than 500 species of plants and trees. They strip plants and trees of their leaves or needles. The foliage die or are weakened and become susceptible to diseases.
The adult moths don’t feed, but they can reproduce rapidly.
State Department of Agriculture crews began hanging traps in foliage, including trees and shrubs, on Monday, June 15. It will take them about three weeks to put up all of the small traps, which are lime-green in color and have a sticky coating inside to capture moths.
The traps, which are effective for about a half-mile range, are checked every two to three weeks before being taken down in September.
Washington has never had a permanent reproducing population of what has been described as the worst forest pest ever brought into the U.S., and agriculture officials want to keep it that way.
“We can’t predict where it might show up because of how they might get here,” Mike Louisell, spokesman for the Department of Agriculture, said of the reason for the annual hunt for the moths.
That’s because they arrive in the Northwest by hitching a ride with people moving or traveling from other parts of the country already infested by gypsy moths, agriculture officials said. They also could come from foreign ships calling at Puget Sound and Columbia River ports.
Trapped moths in one year show where a population of the pest could be developing, and where the Department of Agriculture may need to focus its eradication efforts the following year to get rid of the caterpillars.
And while it’s the hungry caterpillars that do all the eating, officials don’t target them for trapping.
“There isn’t any trap that will catch the caterpillar,” Louisell said. “We trap for the moth because that’s the only effective trap method.”
One European gypsy moth was caught in Whatcom County last summer, in the Lake Whatcom area.
That means more traps will be put up in the Lake Whatcom area this year, Louisell said Monday, June 22, although officials have said that one trapped moth isn’t a huge concern.
The moth trapped in the Lake Whatcom area was among 27 caught in five counties last year, according to the agriculture officials.
The statewide total was much higher than the lone moth found in 2013, and equaled the number found in 2012.
All were European gypsy moths, which was a relief for state officials.
Asian gypsy moth females are of greater concern because they can fly up to 12 miles, making their detection more difficult.
It was the first time a gypsy moth has been trapped in Whatcom County since 2009, when one was caught.
“We don’t anticipate anything unusual,” Louisell said of this year’s effort. “That doesn’t mean it can’t happen, just because you never know, and that’s why we keep trapping.”
Gypsy moths have infested 19 states in the East and Midwest — defoliating millions of acres and causing tens of millions of dollars of damage — since the first European gypsy moth was found in Medford, Mass., in 1869.
Reach Kie Relyea at 360-715-2234 or firstname.lastname@example.org.
The state Department of Agriculture traps adult gypsy moths to track populations and to prevent them from becoming established in Washington.
Adult moths emerge from pupae after 10 to 14 days. They do not feed and live a few days to several weeks. They are present from July through August.
Female: White to cream-colored wings with brown markings, tan body, about 2-inch wingspan.
Male: Smaller than females, dark brown, feathery antennae, with a wingspan of about 11/2 inches.