Trappers find invasive gypsy moths in Brownsville

BROWNSVILLE — Jason Adkins had checked 1,000 traps this summer without finding a moth. 

On Wednesday morning, down a narrow street near Brownsville Elementary, Adkins popped open a bright orange cardboard trap pinned to the trunk of a cherry tree. Inside was a brown insect with broad wings and fuzzy antennae — a gypsy moth. 

"It was pretty exciting," said Adkins, a seasonal employee for the state Department of Agriculture. 

Exciting for a hard-working trapper but worrisome for the neighborhood. 

Adkins is part of a statewide program that monitors for gypsy moths, an invasive species that can ravage forests in places where it becomes established. The Department of Agriculture spread 30,000 traps across the state this summer to keep tabs on the insects and conducted pesticide sprays near Bangor and Graham last spring to eradicate isolated moth populations. 

Adkins and fellow trappers found six male gypsy moths Wednesday near the intersection of Illahee Road and Colorado Street.

"It indicates we probably have a reproducing population in the area somewhere," Department of Agriculture spokeswoman Karla Salp said. 

Immediately after the moths were found, workers set about posting traps in a high-density grid around the site, dotting 256 traps across a 4-square-mile zone. 

"We're trying to find the epicenter of where they're coming from," Salp said. 

Department of Agriculture officials will return to the area next fall to look for gypsy moth egg masses. Hunting down egg clusters is tough — moths will lay eggs on any surface, natural or artificial, often hidden from view — but searchers found female moths along with egg masses for the first time last summer in Graham.

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"It's like a needle in a haystack," gypsy moth trapping supervisor Tracy Shirek said. "But we have been successful in finding them." 

Spray treatment not guaranteed

Salp said the gypsy moths discovered Wednesday won't automatically put the Brownsville area in line for pesticide treatment next spring. She said officials review data on captured moths at the end of each trapping season and determine how best to respond.

If a spray is necessary, the department would likely begin notifying residents in January, Salp said. The state uses a biopesticide called Btk to kill caterpillars. 

The moths captured in Brownsville will undergo DNA analysis to determine whether they are European gypsy moths or Asian gypsy moths. 

Asian gypsy moths typically arrive in North America on vessels docking in West Coast ports. Both male and female Asian gypsy moths can fly long distances, making the species a malignant threat to the state's forests. Trappers last caught Asian gypsy moths in Washington in 2015. 

European gypsy moths, which have spread across some East Coast and Midwest states, expand their territory more gradually, in part because the females can't fly. Seventeen European gypsy moths were trapped in Kitsap last year. 

To catch a moth

Capturing gypsy moths is all about wooing the males. 

The cardboard traps, shaped like miniature tents, come with a lure coated in synthetic pheromone that mimics a chemical released by female moths to attract mates. Trappers post the devices on tree trunks where the breeze will carry the pheromone across the landscape.

Male moths can pick up on the chemicals from more than a mile away. The eager suitors crawl into the trap where a sticky coating ensnares their bodies. Trappers log each trap using GPS and check them every two to three weeks between June and September.

Adkins, a Suquamish resident, keeps tabs on more than 1,000 traps across the Kitsap Peninsula. He checks up to 100 a day, winding down back roads across the county to reach his trap sites. 

Gypsy moth monitoring is important work, Adkins said, "but it can be pretty monotonous." 

Traps have to be checked frequently because the adult moths may live for only a few days or weeks in order to breed. Finding the moths soon after they're trapped gives officials a better chance of catching more and homing in on an infestation, Salp said. 

Female moths lay eggs in summer and early fall. Caterpillars hatch from the eggs in the spring and feed voraciously before entering their pupal stage. 

In states where gypsy moth populations are permanently established, caterpillars cause spectacular damage during their short lives, feeding on hundreds of tree and shrub varieties. 

"They'll totally devastate the area where they are, then they'll move on to a new area," Salp said. 

Gypsy moths are inadvertently carried across the country by people moving between states. Washington has monitored for the insects since the 1970s to ward off large-scale infestations. 

Salp said that while the moths typically feed leafy trees and bushes, they'll still gnaw the needles off an evergreen. 

"They prefer deciduous trees," she said. "But they'll eat a spruce."

For more information, go to agr.wa.gov.