Thousands of hungry insects are playing a vital role in stemming the spread of knapweed, Dalmatian toadflax and other noxious weeds in northeast Washington.

Noxious weeds, so designated by the Washington State Noxious Weed Control Board, are non-native plant species. Because of their aggressive growth and lack of natural enemies, they are regarded as potential threats to the state.

"There were no insects, plant diseases or other predators to keep these weed populations in check when they were brought over here in wildflower mixes or as contaminants in seed crops," said Dan Fagerlie, WSU Cooperative Extension, Ferry County.

Research in Montana has documented a significant increase in water runoff and stream sedimentation where knapweed has displaced native bunchgrass, according to Fagerlie. "If the water runs off in the springtime rather than percolating through the watershed, it has a dramatic effect on late summer stream flows and everything else that is critical for fish."

The sediment can fill in gravel beds where salmon and bull trout deposit eggs. "You are disrupting a whole portion of the food chain when an invasive species becomes a monoculture," Fagerlie said.

A 1986 Cooperative Extension survey found that 56,000 of the 600,000 acres of grassland, range and timberland in Ferry County were infested with diffuse knapweed. Fagerlie estimates that perhaps 70,000 to 75,000 acres are infested now, counting areas that have been sprayed, but still have seed. He thinks the situation could have been much worse.

"If we hadn't done a coordinated spray program and used bioagents to reduce the rate of spread, I would say that about 90 percent would have been covered by now.

In collaboration with the U.S. Forest Service, Washington State University and the USDA Animal Plant Health Inspection Service (APHIS), a consortium of concerned organizations in the region, decided to expand the use of bioagent insects in the battle against weeds about four years ago.

"We were losing ground," Fagerlie said. "No matter how much herbicide we utilized, they kept spreading in other areas, especially in the national forests and surrounding areas."

Fagerlie assumed responsibility for coordinating the bioagent enhancement project for the consortium, which includes the extension offices and weed boards in Ferry, Stevens, Pend Oreille and Okanogan counties, and the Colville Confederated Tribes. He put together a comprehensive program to boost procurement distribution and establishment of available insects. He also developed an educational package and a Power Point presentation for landowners and agencies on using biocontrol.

Diffuse knapweed plant whose root has been mined by Cyphocleonus achates.

Larinus minutus pupa in a diffuse knapweed seed head. One immature (larva) can destroy all of the seeds in a diffuse knapweed seed head. The adults will also feed on the plant.

Since 1999, Fagerlie, working with APHIS, Piper, and a long list of collaborators in the four northeast counties have released more than 160,000 insects at 480 sites in the four counties, including Cyphocleonus achates, a large insect that attacks spotted and diffuse knapweed.

The larval stage of the insect burrows into the root system of knapweed plants. "Three or four can sometimes kill the plant outright," Piper said.

Daro Palmer, extension bioagent coordinator in Ferry County, has added a research component to the effort as part of master's degree work at WSU. Using global positioning, Palmer has recorded the locations where bio-agents were released in 1999, 2000 and 2001. He also is keeping track of release site information, such as soil type, moisture conditions, type of vegetation in the area and information about the weed infestation. The whole idea is to figure out why some insect releases fail.

"This is one area of biocontrol where there's not a lot of research," said Piper, who is Palmer's major professor.

The Stevens County Weed Board is producing interactive maps on compact disks for the project's collaborators.

"We can track sites, correlate factors with success, and hopefully down the road, we may be able to change bioagent releases from a hit-and-miss operation to treatments," said Palmer.

Landowners already are reporting results. "Some are very happy already," Fagerlie said. "I was with one recently who was tickled pink because for the first time he's seen a decrease in diffuse knapweed on a mountainside where he usually has a helicopter spray.

"People are looking for a low-cost alternative for their weed problems," Piper said. "Fortunately we have quite a few good agents available right now on some really hard-to-control weeds."

Fagerlie's and the team's success has not gone unnoticed. Earlier this year he was honored by the U.S. Forest Service for leadership and coordination of a multi-agency, multi-county effort to control noxious weeds on public and private lands. Region 1 of the U.S. Forest Service presented Fagerlie with a "Caring for the Land Award."

Expansion for the biocontrol project is in the works. "It has been held up as a model for the whole state," Fagerlie said. "The Forest Service is proposing to expand bioagent work in south central and western Washington in coordination with Piper and the APHIS."