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Management <br />Diffuse and spotted knapweed can be managed similarly. !bey are readily controlled with herbicides. Ilowever. the <br />needs will reinvade unless cultural techniques are used <br />Chemical Control of Spotted Krapweed <br />Research conducted at Colorado State University indicates that 1 ordon 22K (piclorarn) at I to 2 ptA. fr.â–ºnsline <br />(clopyralid) at 0.67 to I pt/A, Curtail (clopyralid + 2,4 -1)) at 4 to 6 pt A, or 13anvel'Vanquish %Clarity (dicamha) at 1 to 2 <br />ptA control diffuse knapwecd. Tank mixes of 13anvel'Vanquish (lanty plus 2.4 -I) at 1 pt 2 pt/A or <br />l3anvel'Vanquish`Claruy plus 'I ordon 22K at 1 to 2 pt + U 5 to I pt/A or 1 ordon plus 2.4 -1) at 0 75 pt + 2 pt'A all <br />control diffuse knapweed these tank -mixes may save mono and reduce grass injury resulting from higher use rates of <br />a single herbicide <br />Spotted knapweed and diffuse knapweed generally, occupy the same areas in Colorado. so the same herbicide treatments <br />can be applied Weed scientists at Montana State 1 tnrversity indicate that 1 pt/A of'fordon (0 25 lb) controls spotted <br />knapweed tor two to three years, but the weed will reinvade the area unless other management techniques are used. <br />Mechanical Control of Spotted Knapweed <br />If desirable grass competition is evident in diffuse or spotted knapweed stands, judicious herbicide application that does <br />not injure grasses may allow them to compete effectively with the weeds. Irrigation (where possible) may help stimulate <br />grass competition in these cases. However, infested rangeland or pastures often are degraded, allowing knapweed <br />invasion, and herbicides alone will not restore the land to a productive state. Seeding suitable perennial grasses is <br />necessary to prevent weed reinvasion. <br />Diffuse knapweed <br />