Oregon to Begin Gypsy Moth Eradication Projects

Aerial spray projects planned for St. Helens and Bend.

Photo: Oregon Department of Agriculture

(SALEM) - The latest battle in the war against the plant-eating gypsy moth in Oregon is about to begin this spring in St. Helens and Bend as the Oregon Department of Agriculture prepares to once again keep the invasive insect species from establishing in the state.

The 2007 gypsy moth eradication efforts include the first ever project east of the Cascades and only the third time ODA has dealt with the Asian variety of gypsy moth.

"We had no gypsy moth eradication projects in 2006, so this is a big year for us," says Kathleen Johnson, supervisor of ODA's Insect Pest Prevention and Management Program. The Gypsy moth is not native to Oregon and is considered a serious pest of trees and shrubs.

ODA's goal is to prevent negative economic and environmental damage to Oregon by loss of foliage on trees, restrictive quarantines on commodities, or loss of favorable fish habitat due to degraded watersheds.

After a couple of years of a relatively low number of gypsy moth detections in Oregon, activity picked up during last summer's statewide trapping program.

A total of 66 gypsy moths were found in traps throughout the state - up from only nine detections in 2005.

Of the 66 gypsy moths trapped last year, 57 were detected in a residential area of Bend, in central Oregon.

That followed the detection of a single moth in Bend in 2005. A higher density of traps placed in the area confirmed a breeding population of gypsy moths.

Never before have so many gypsy moths been trapped east of the Oregon Cascades. ODA entomologists found additional evidence that pointed to a problem.

"When you find 57 gypsy moths in an area, as well as live female gypsy moths and live egg masses, you know you have a reproducing population," says Johnson.

In Bend, three aerial applications of the biological insecticide Bacillus thuringiensis var. kurstaki (B.t.k)- which specifically targets the insect, and has been safely and effectively used in gypsy moth projects for more than 20 years in Oregon -- will take place during the month of May on a 533-acre site that includes residential and other properties located primarily between U.S. Highway 20 and U.S. Highway 97. The three applications are scheduled to take place 14 days apart, weather permitting.

Introductions of gypsy moths in Oregon can usually be traced to vehicles or outdoor household articles originating from infested areas of the northeastern U.S. When people move to or visit Oregon from these infested areas, the gypsy moth or its eggs hitches a ride.

In this case, the Bend infestation is believed to have originated from a car purchased from the East Coast via the internet. When the car arrived, so did the gypsy moth- unwittingly by the new owner. ODA was able to find egg masses, pupal cases, and other gypsy moth life stages on parts of the vehicle last summer.

The second project involves 640 acres in St. Helens, near the Columbia River and U.S. Highway 30. The eradication effort is in response to last year's detection of one Asian gypsy moth.

This version of the insect pest is potentially much more serious, therefore requiring immediate attention even if only one moth is trapped.

Unlike the more common European gypsy moth, female Asian gypsy moths are strong fliers and are attracted to lights, allowing populations to spread much more rapidly. In addition, the Asian gypsy moth feeds on a broader range of host trees, including conifers.

Once again, three aerial applications of B.t.k. are scheduled for St. Helens 14 days apart, weather permitting. The first application is set for next Tuesday, April 24.

Areas of the Columbia River are at greater risk for the introduction of Asian gypsy moths due to cargo ships arriving from infested areas in Asia.

ODA had previously treated for Asian gypsy moth in North Portland and Portland's Forest Park- both located next to the Columbia River.

The eradication projects will overlap another important component of ODA's gypsy moth program- the detection phase.

Next month, the first of thousands of traps will be placed throughout the state to monitor any emerging problems with gypsy moth.

These tent-like traps contain a female pheromone that attracts male gypsy moths that might be in the area. They will be checked and eventually removed after the summer months.

There are seven other sites in Oregon where gypsy moth detections were made last year but no eradication efforts are planned this spring.

They include Portland, Eugene, Damascus in Clackamas County, Shady Cove in Jackson County, and O'Brien in Josephine County. Shady Cove and Eugene are repeat sites as gypsy moths were also detected in 2005.

All sites where gypsy moths were detected last year will receive extra attention this spring as a higher density of traps are placed in those areas.

If no additional gypsy moths are trapped in St. Helens and Bend the next two years, ODA will officially declare the eradication efforts successful.

In both Bend and St. Helens, ODA officials want to act quickly before the population of gypsy moths becomes established or more difficult to control. In the mid-1980s, more than 225,000 acres were sprayed in Lane County alone after some 19,000 gypsy moths were trapped.

"Our goal is to find the gypsy moth introductions soon after they arrive and then eradicate them quickly before they have time to spread," says Johnson. "That way, fewer people are impacted by the programs. This seems a much better way to go than allowing Oregon to become generally infested with gypsy moth. Back east, where gypsy moth populations cannot be eradicated and people have to learn to live with them, residents themselves often contract with aerial applicators to spray their neighborhoods just to keep the leaves on the trees. They continually have to confront an insect that has a big impact on their lives."

Oregon's zero tolerance policy for gypsy moth is still in force as the state still has a chance to keep the nasty insect pest from becoming a permanent resident.