Washington State University -- Impact 2006
Biological Weed Control Spreading Across WashingtonSUMMARY
- Biological weed control, in the form of insects, is replacing or supplementing the use of pesticides across Washington for invasive weed management. These weeds threaten valuable native grasslands and timberlands by reducing biological diversity, lowering land values and uses, and increasing soil erosion. A biocontrol project was developed in Washington to provide an organized approach for implementing biocontrol by educating land managers and providing biocontrol agents, expertise and customized field recommendations.
ISSUE
- Washington State is facing an invasion of non-native, highly invasive noxious weeds, including diffuse, meadow and spotted knapweed, purple loosestrife, tansy ragwort, St. Johnswort, houndstongue, orange hawkweed, meadow hawkweed, Scotch broom and Dalmatian toadflax. For example, about 60,000 acres have been infested so far in Ferry County alone and more than 400,000 acres are threatened. Non-native noxious weeds destroy biological diversity, decrease forage, increase erosion potential, and decrease land values across the state and western USA. The health of these grasslands and timberlands is vital for wildlife, livestock, and people of Washington. Washington State land managers often do not have the time, funds or expertise to implement biocontrol as part of their own integrated weed management strategies. Our project addresses this need by educating and engaging land managers for better understanding and use of biocontrol to solve their own weed problems.
WHAT HAS BEEN DONE
- More than 286,000 insects were released at 419 sites in Washington in 2005. GPS locations were taken and are being used to map these sites. Characteristics such as soil type, precipitation, slope, aspect, and size of weed infestation were recorded to enable future evaluation of the releases. Project staff worked with USDA-APHIS to facilitate the distribution of over 77,000 insects from insectary sites in Washington to four other western states to control Dalmatian toadflax, a very aggressive, hard to control weed. Six new biocontrol agents were released in the project area to help control the following four weed species: meadow knapweed, Scotch broom, puncturevine, and bull thistle. Project staff worked with the Okanogan and Ferry County weed boards and officials in British Columbia to produce 29,000 pamphlets in order to alert the public to the new weed invader hoary alyssum. Pamphlets were distributed to private landowners, public land managers, and public officials in both countries. Staff also developed handouts and posters on weed identification and control, as well as posters to increase public awareness of biological weed control. The posters were displayed at functions in Washington, Oregon, and British Columbia. During the year, project staff made 58 presentations related to the management of non-native weed species. They addressed county commissioners, cattle producers and various other audiences. Presentations were also delivered at the first Dalmatian Toadflax Meeting in Coeur D'Alene, the Regional and National Intertribal Agriculture Council Conference, National Invasive Weed Awareness Week in Washington D.C., and the International Farm and Family Forestry Conference in Vilnius, Lithuania. Finally, a rapid response plan was initiated to control new invasive weeds including hoary alyssum on USFS land, yellow toadflax, and Balkan catchfly.
IMPACT
- Biocontrol has resulted in a substantial reduction of diffuse knapweed in large tracks of land in eastern Washington and is already reducing the health and rate of spread of Dalmatian toadflax infestations. Grass density appears to be higher than it has been in over 24 years. This has been quantitatively measured at a diffuse knapweed site in northern Ferry County. Diffuse knapweed biomass has declined from 1860 lbs/acre in 1984 to less than 10 lbs/acre in 2004 with grasses returning. In Ferry County alone, diffuse knapweed has been suppressed over an estimated 20,000+ acres with similar results in Okanogan County and on the Colville Reservation. There has also been a corresponding reduction in the amount of pesticides used to control knapweed. Pesticide reductions are expected to continue to increase over the long-term as the invasive species is further reduced by biocontrol agents. This has and will result in a substantial decrease in expenditures for weed control in Washington counties and improve environmental quality because biocontrol agents are self-perpetuating and reduce the need for repeated applications of pesticides. In addition to quantitative impacts, the project has had significant success in less direct ways. Interest in biocontrol is growing, and weed managers such as Tom Bertram in Pierce County appreciate the expertise and regional approach offered by this project, “We have always felt that an organized effort was needed to bring more attention to the use of biocontrol agents in our fight against Washington state noxious weeds”. As the project has expanded into central and western Washington, the number of collaborating counties, agencies, and individuals has grown rapidly. In 2005, the number of western Washington counties participating in the project increased more than two-fold, as did the number of insect releases. In addition to county weed boards and private landowners, new project participants include private industry, municipal utilities, state parks, and military bases. While the number of collaborators implementing biocontrol is growing, their reliance on chemicals is lessening.
PRIMARY AREA OF IMPACT
- Extension
FUNDING:
- Ferry County
U.S. Forest Service
Colville and Okanogan national forests
Confederated Tribes of the Colville Reservation
Smith-Lever 3(b) &( c)
Douglas County
Pend Oreille County
Stevens County
Okanogan County
King County
Stevens County Weed Board
Okanogan County Weed Board
Washington Dept. of Fish and Wildlife
Pierce County Weed Board
COUNTIES:
- The principal counties served are Chelan, Clallam, Clark, Douglas, Ferry, Island, Jefferson, King, Kittitas, Klickitat, Lewis, Okanogan, Pend Oreille, Pierce, San Juan, Skamania, Snohomish, Stevens, Thurston, Wahkiakum, Whatcom, Yakima
CONTACT:
- Dan Fagerlie, Director, WSU Ferry County Extension
Washington State University
509-775-5235 (Phone)
509-775-5218 (FAX)
fagerlie@wsu.edu