Almost all CRP fields in Minnesota contain primary and secondary noxious weeds, particularly Canada thistle and quackgrass. Gopher mounds are found in almost half of the CRP fields in Minnesota, but severe mounding occurs in only 10 percent.
Control is necessary when mounding inhibits cropping or grazing.
The State of Minnesota categorizes weeds as primary or secondary noxious weeds. Primary noxious weeds are an economic problem wherever they grow, causing harm to public health, public roads, crops, livestock, and other property. Secondary noxious weeds are designated by individual counties for additional control. According to a University of Minnesota survey of 151 CRP fields, Canada thistle is the most common primary noxious weed. About 70 percent of CRP fields contain Canada thistle, where it covers 2 to 3 percent of the ground.