ARS | Publication request: THE MOST FREQUENTLY LISTED NOXIOUS WEEDS IN THE UNITED STATES AND SOUTHERNCANADA.

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 13, 2000
Publication Date: September 1, 2000
Citation: Skinner, K.M., Smith, L., Rice, P. 2000. The most frequently listed noxious weeds in the united states and southerncanada. Weed Science. 48:640-644.

Interpretive Summary: More than 5,000 species of alien weeds have established in North America some of which have infested large areas and caused losses of crops, forage, and native species. Many states have passed "noxious weeds" laws which req- uire control of designated harmful plants, but information on which states list which weeds as noxious is not readily available. We compiled a data- base of noxious weed lists obtained from 48 states and six provinces to identify the most commonly regulated weedy plants in the United States and southern Canada. The most frequently listed weeds are Canada thistle, field bindweed. Russian knapweed, johnsongrass, musk thistle, quackgrass, loosestrife, and leafy spurge. Biological control programs have targeted many of the top weeds of national concern, but none of the weedy grasses. The complete database is on the Internet at http://invader.dbs.umt.ed. This information may be used by resource managers and regulatory officals in assessing which weeds are problematic in adjacent geographic areas and by researchers to select which weeds to target with new biological control programs.

Technical Abstract: To identify the most commonly regulated weedy plants in the United States and southern Canada, we compiled a database of noxious weed lists obtained from 48 states and six provinces. The most frequently listed weeds are Canada thistle, field bindweed, Russian knapweed, Sorghum spp., must thistle, quackgrass, Lythrum spp, and leafy spurge. When genera are ranked dthe top genus is Centaurea, which includes spotted and diffuse knapweed an yellow starthistle. Biological control programs have targeted many of the top dicotyledonous weeds of national concern, but none of the weedy grasses and sedges. The complete database is on the Internet at http://invader.dbs. umt.edu. This may be used by resource managers and regulatory officials in assessing which weeds are problematic in adjacent geographic areas and by researchers to select which weeds to target with new biological control programs.