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Weeds: Fight nature with nature

The approach of summer often brings with it delightful thoughts of gardening, scenic drives and nature watching. What could mar this beauty? Weeds!

Washington is home to more than 500 weed species, 129 of which are noxious or non-native species. Though annoying pests to gardeners, weeds also cause statewide problems to acres of open terrain — far more than a bottle of weed spray can cure.

To combat the destruction noxious weeds cause to the environment — such as disturbing plant communities, livestock grazing, wildlife habitat and water quality — WSU Extension is fighting nature with nature through its Invasive Weed Species Bioagent Enhancement Program, with regional project coordinators working out of Ferry County, King County and Wenatchee.

The program, which officially began in 1999, uses living organisms, mostly insects, to suppress weed populations in highly vulnerable areas such as low-productivity or nonfarming lands.

Though these areas may seem unimportant to most people, said Dan Fagerlie, director of Ferry County Extension, the long-term burdens that spreading these weeds pose to land, water and agriculture impact everyone in the state regardless of location.

“Weeds affect all taxpayers and landowners,” Fagerlie said.

“Weed seeds, sprigs and burs get caught in clothing, shoes, vehicles and pets and are thus distributed to land areas across the state. This land is valuable for wildlife habitat, grazing, crops, recreation and as watersheds — uses that directly or indirectly affect us all” he added.

However, the Ferry County program, working in conjunction with public agencies including the USDA, U. S. Forest Service, the Confederated Tribes of the Colville Reservation, USDA-APHIS, WSU Extension offices and county weed boards, has proved successful in already improving more than 20,000 acres in Washington. The future will see much greater impacts since insects from the project are being distributed across Washington and the western United States.

Unlike sprays or other weed killing methods, the use of weed-eating insects typically requires only a single treatment per site. Insects also can find isolated areas where vehicles and sprays cannot reach, and they are safe in environmentally sensitive areas, like near water sources.

The use of bioagents is saving taxpayers millions of dollars, Fagerlie said, because without the insects, several invasive, non-native weeds would continue spreading at an exponential rate. For every dollar spent on biological weed control, $30 is saved, compared to $5 saved per dollar spent on herbicides, according to an assessment by Gary Piper, WSU Extension entomologist.

However, Fagerlie warns that bioagents are not a miracle fix to the state’s weed problems.

“People think bioagents are a cure-all, but they only work effectively in some sites,” Fagerlie said. “They’re just one tool in the tool chest.”

Though valuable, biological weed control can take five to seven years before the effects are visible, and it may need to be used in conjunction with other weed control methods.

Insects are screened for up to 10 years before they are released as bioagents, but there is always the possibility, even if remote, that they could adversely impact nontarget and/or native species.

“There are no guarantees in the biological world,” Fagerlie quoted from one of his past professors. Further studies are being conducted on improving and/or safeguarding bioagent use through USDA and other extension offices and universities, including Cornell University and the University of Colorado. Both of the latter have graduate students working in conjunction with this WSU project.

Ferry County Extension also is working to educate the public on weed identification and integrated control strategies. Through presentations at fairs and expos and distribution of flyers across Washington and Canada, extension offices and related public agencies are hoping to raise awareness, prevent new weed problems and reverse land disruption.

”People care about the future of the land,” Fagerlie said. “Ferry County is looking at the weed problems across the state and working to solve them.”

For more information on bioagents and tips on how to stop the spread of noxious weeds, visit

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