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Diffuse Knapweed

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Diffuse knapweed
Diffuse knapweed, flowers - USDA APHIS PPQ, Oxford, North Carolina
Scientific Name: 

Centaurea diffusa Lam. (ITIS)

Acosta diffusa (Lam.) (ITIS)
Common Name: 
Diffuse knapweed, white knapweed, spreading knapweed, tumble knapweed
Native To: 

Eastern Mediterranean region (Winston et al. 2012)

Date of U.S. Introduction: 
Means of Introduction: 

Introduced accidentally through contaminated seed (Zouhar 2001)


Reduces agricultural yields and forage values; crowds out native species (Winston et al. 2012)

Distribution / Maps / Survey Status

University of Georgia. Center for Invasive Species and Ecosystem Health.
Provides state, county, point and GIS data. Maps can be downloaded and shared.


University of Georgia. Center for Invasive Species and Ecosystem Health.


Google. YouTube; Montana Weed Control Association.

Selected Resources

The section below contains highly relevant resources for this species, organized by source. Or, to display all related content view all resources for Diffuse Knapweed.

Council or Task Force

Invasive Species Council of British Columbia (Canada).

See also: Publications for more resources

Alberta Invasive Species Council (Canada).

See also: Fact Sheets for more information about individual invasive species, including those listed as "Prohibited Noxious" and "Noxious" under the Alberta Weed Control Act

Washington State Recreation and Conservation Office. Washington Invasive Species Council.

IUCN. Species Survival Commission. Invasive Species Specialist Group.
University of Georgia. Center for Invasive Species and Ecosystem Health.
Federal Government

USDA. FS. Forest Health Technology Enterprise Team.

See also: Invasive Species Publications for more publications
USDA. FS. Rocky Mountain Research Station. Fire Sciences Laboratory.
USDA. NRCS. National Plant Data Center.

USDA. ARS. National Genetic Resources Program. GRIN-Global.

State and Local Government
Washington State Noxious Weed Control Board.

Wisconsin Department of Natural Resources.

California Department of Food and Agriculture.
See also: Included on California's noxious weed list; see Encycloweedia: Program Details for additional resources

King County Department of Natural Resources (Washington). Water and Land Resources Division.

Colorado Department of Agriculture. Conservation Services Division. Noxious Weed Program.

University of California. Weed Research and Information Center.
See also: Weeds in Natural Areas for more information sheets
North Dakota State University. Extension Service.
University of Nebraska - Lincoln. Cooperative Extension.
Colorado Weed Management Association.
Montana Weed Control Association.