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Page 12 of 23 <br />Management <br />Appendix l <br />Dittuse and spotted knapweed can be managed similarly. They are readily controlled with herbicides <br />i-iowever, the weeds will reinvade unless cultural techniques are used. <br />Chemical Control of Spotted knapweed <br />Research conducted at Colorado State Iniversity indicates that Tordon 22K (picloram) at I to 2 pt/A, <br />'Transline (clopyralid) at 0.67 to 1 pt/A, Curtail (clopyralid + 2,4-D) at 4 to 6 pt/A, or <br />Banvel/Vanyuish/Clarity (dicamba) at I to 2 pt/A control dit~'use knapweed 'Tank mixes of <br />Banvel/Vanquish/Clarity plus 2,4-D at I pt + 2 pt/A or Bam~elNanyuish/Clarity plus Tordon 22K at 1 to 2 <br />pt + U.5 to t pt/A or'Tordon plus 2,4-D at 0.75 pt + 2 ptlA all control diffuse knapweed. These tank-mixes <br />may save money and reduce grass injury resulting from higher use rates of a single herbicide. <br />Spotted knapweed and diffuse knapweed generally cx:cupy the same areas in Colorado, so the same <br />herbicide treatments can be applied. Weed scientists at Montana State University indicate that I pt/A of <br />Tordon (025 Ib) controls spotted knapweed for two to three years, but the weed will reinvade the area <br />unless other management techniyues are used. <br />Mechanical Control of Spotted knapweed <br />If desirable grass competition is evident in ditluse or spotted knapweed stands, judicious herbicide <br />application that does not injure grasses may allow them to compete effectively with the weeds. !rogation <br />(where possible) may help stimulate grass competition in these cases. Ifowever, infested rangeland or <br />pastures often are degraded, allowing knapweed invasion, and herbicides alone will not restore the land to a <br />productive scale. Seeding suitable perennial grasses is necessary to prevent weed reinvasion <br />Diffuse knapweed <br />