Gypsy moth eradication set near Yacolt

o What: Open house meeting on proposed gypsy moth eradication. State officials detected a reproducing population of gypsy moths in north Clark County last year.

o When: 6:30 to 8 p.m. Feb. 17.

o Where: Yacolt Primary School, 406 W. Yacolt Road, Yacolt.

When 16 gypsy moths turned up in traps near Yacolt last year, it was enough to catch the attention of the state Department of Agriculture.

That number of moths was more than trapping efforts detected anywhere else in Washington. State officials also found a fresh egg mass capable of producing up to 1,000 more gypsy moth caterpillars. They also found a “spent” egg mass, pupal cases and cast skins — suggesting the destructive pest was already reproducing in the area.

“We consider it a serious threat to the environment when we encounter a reproducing population of gypsy moths,” said Mike Louisell, a Department of Agriculture spokesman.

Now the state is planning an eradication project aiming to wipe out the gypsy moth population in north Clark County. Officials will use aircraft to drop insecticide over a 220-acre area outside Yacolt this spring. The state plans three aerial applications of a biological insecticide known as Btk in April and May. The agriculture department will host a public meeting in Yacolt next month to discuss the plan.

o There are 19 states where invasive gypsy moths have become permanently established. Washington is not one of them.

The proposed eradication area encompasses 14 homes and includes a section of Cedar Creek northeast of Yacolt. Among the landowners is timber company Weyerhaeuser. Much of the terrain is rugged, which is partially why officials chose to apply insecticide from the air instead of the ground, Louisell said.

The gypsy moth isn’t considered a threat to industrial timber production, said Weyerhaeuser spokesman Anthony Chavez. But the company has cooperated with eradication plans and welcomes the effort, he said.

“The moth does not have an effect on Douglas fir, but it is harmful to hardwoods and some of the ecosystems we manage,” Chavez said.

The insecticide, used for decades, isn’t considered dangerous to humans or the environment, Louisell said. Officials will, however, ask residents in the eradication area to stay inside for 30 minutes while it’s applied, he said. But that’s not necessary, he added.

“It does have a good safety record — a long, proven safety record,” Louisell said.

The state reached out to Clark County about the proposed eradication last month, said Kevin Tyler, a division manager in the county’s Environmental Services department. Other than that, the county doesn’t play a role in the gypsy moth operation, he said.

Gypsy moths have long been on the radar of Washington, Louisell said. The pests are much more common elsewhere in the United States, but can be brought to the Northwest with arriving people, he said. Once here, the gypsy moth can quickly spread and cause significant damage to urban trees and forests, according to the agriculture department.

“It’s not a native pest to this area,” Louisell said. “It doesn’t have natural enemies that can limit its spread.”

The moths found near Yacolt are European gypsy moths — not the higher-risk Asian gypsy moths, which can fly farther and are harder to detect.

The state has carried out 92 eradication operations since the 1970s, Louisell said. The last one in Clark County occurred in the Mount Vista area in 1998, he said. This year’s eradication near Yacolt is the only such project planned in Washington in 2015. No such operation happened in 2014.