State plans to spray area to eradicate gypsy moth.

Byline: Scott Maben The Register-Guard

The state will spray a biological insecticide over a residential neighborhood in south Eugene this spring to combat a small outbreak of the gypsy moth, a pest that infested central Lane County 20 years ago and prompted a massive spraying program.

The preliminary plan is to treat a 183-acre area along Crest Drive between Morse Ranch Park and Crest Drive Elementary. A helicopter would spray Bacillus thuringiensis kurstaki, or Btk, on three days in April or May, department spokesman Bruce Pokarney said Thursday.

The insecticide kills all moths and butterflies that are in the caterpillar stage and that are feeding at the time of spraying. It does not harm other insects or wildlife, pets or humans, state officials said.

However, people will be advised to stay indoors at the time of spraying, Pokarney said.

Officials will hold a public meeting later this month or early next month to brief residents on the proposal. They also plan to meet with parents of Crest Elementary students Jan. 20 as well as with the Crest Drive Citizens neighborhood association.

"We think it's extremely important people understand both the threat the gypsy moth brings as well as the precautions we are taking to eliminate the problem and have the least impact on people in the area," Pokarney said.

The moth is a voracious eater, stripping leaves from oaks, alders, willows and many ornamental trees and shrubs. In time, defoliation will weaken and can kill the vegetation.

"Even a single year can be devastating," said Kathleen Johnson, supervisor of the department's Insect Pest Prevention and Management Programs.

The state is proposing the insecticide treatment because of a cluster of gypsy moths caught in a trap in an oak tree near Crest Drive and Courtney Place last summer. Sixteen male moths were found in one trap and another moth was found in a nearby trap.

Officials then found more evidence of the problem: female moths laying eggs, old and new egg masses, and pupal skins.

"There's the strongest evidence we can find that we have a breeding population," Pokarney said. "Seventeen is what we trapped; that's an indicator of a much larger population."

Only seven other moths were caught in traps last year in the entire state. Agriculture officials placed 16,000 traps in trees in 2003 as part of an ongoing program to find gypsy moth outbreaks early.

Most years, the state finds enough moths in an area to trigger spraying, usually west of the Cascades. Last year, it was in southeast Lincoln County. In 2001, 160 acres were treated in Ashland. Outbreaks near Cottage Grove and Veneta prompted spraying in the 1990s.

The moth infiltrates areas with the help of humans - usually by hitching a ride as eggs on vehicles and household items moved from Northeastern states, where infestations are widespread.

"They'll lay eggs anywhere they can find a dark, secluded place," Pokarney said. "So you pack up all this stuff and move out to Oregon, and lo and behold, the eggs may hatch here."

Officials say it appears a family that moved to the Crest Drive area from Connecticut in 2000 brought the gypsy moth eggs with them.

The female moth does not fly, but outbreaks still can spread quickly through artificial movement of egg masses, Johnson said. Larvae also can climb up a tree, catch a wind current and "balloon some distance away," she said.

"That's how we would expect them to be moving in that area - ballooning of the larvae," she said.

The 183-acre proposed spray area is large enough to ensure successful eradication, officials said. Three treatments, each seven to 10 days apart, are required. The Btk would be applied as a mist to coat leaves eaten by the caterpillars.

"It will bind up in their gut and they end up starving to death," Pokarney said.

Conditions needed for Btk to be activated are found only in the stomach of moth and butterfly caterpillars, not in animals, birds or other desirable insects, according to the state Department of Human Services.

The agency said Btk has an excellent safety record for humans; it's commonly used on commercial and even some organic produce.

A similar insecticide known as Bt was used in the Eugene-Springfield area from 1985 through 1988 to fight a huge gypsy moth infestation. In 1984, 19,000 moths were discovered in local traps, and the state jumped to action. Quarantines were placed on Lane County wood products and nursery plants.

For the next four years, helicopters appeared over south Eugene at dawn each spring to shower caterpillars with Bt, then an unproven weapon against an army of the moths.

The state sprayed Bt over 225,000 acres in the area in 1985 and 190,000 acres in 1986. Officials declared victory in 1989 after monitoring showed that few moths survived.

It remains the largest gypsy moth eradication west of the Rocky Mountains, costing tens of millions of dollars.

It also was heralded as a model in the war on the gypsy moth, the result of a raging debate and court case over whether the state should use a chemical or biological insecticide in the heavily populated area.

The Eugene-based Northwest Coalition for Alternatives to Pesticides was one of several groups that helped persuade the state to try Bt.

Norma Grier, the coalition's executive director then and now, said many residents worried about the spray despite official assurances of its safety. "It freaked folks out," Grier said. "Bt was everywhere in this community. So 183 acres is more modest than what this community faced 18 years ago."

She said Bt isn't entirely benign, noting the mortality on other moths and butterflies that may take years to repopulate treated areas.

"Bt has a narrower impact than some other broad-spectrum insecticides, but we are kidding ourselves if we think there isn't harm done," she said.

But Grier stopped short of saying the state should not go forward with spraying this spring.

"I'm inclined to say I need to learn a little bit more," she said.

STOPPING THE GYPSY MOTH

To learn more about the gypsy moth: Oregon Department of Agriculture: www.oda.state.or.us/Plant/ppd/Ent/Gypsy_moth.html

To learn more about Btk: Oregon Department

of Human Services: www.dhs.state.or.us/publichealth/pesticide/btkfacts.cfm