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Pace 1 I of 2; <br />Chemical Control of Russian Knapi eed <br />Appendix I <br />In most circumstances, an herbicide alone will not effectively manage Russian knapweed. However, there <br />may be situations where desirable plants within a Russian knapwced Inlestation may compete cf'tccnvcly <br />with the weed if it is stressed with a single \vecd management technique. When integrating chemical and <br />cultural control, avoid using herbicide rates that injure grasses because effectiyc competition will be <br />reduced. <br />Russian knapwced is controlled with Tordon 22K (picloram) at 1 to 2 quarts/A. Tordon may be broadcast <br />sprayed up to I quart'.\ or spot sprayed at rates up to 2 quarts, A. Tordon plus 2,1-D ( I to 1.5 pints + I <br />quart. A) also will control Russian knapweed. If lo\% rates of Tordon or Tordon plus 2.4-D are used. <br />application for two consecutive years may be necessary to achieve adequate control. Apply Tordon any <br />time the Tweed is Ictiycly growing. <br />For Telar (chlorsulfuron), a noncrop herbicide that controls Russian knapwced, application timing is <br />critical. Apply ( I ounce,A) when Russian knapwced is in the bloom to postbloom stage. Earlier <br />applications do not control the weed cf1ectiycly. Fall is a good tune to apply T clar, but it may Injure smooth <br />brume or other hrome species. Always add a good agricultural surfactant at 0.25 to 0.5 percent wy to the <br />spray solution. Escort (mct,ulturon) is labeled for pasture and rangeland use Apply it at 0.75 to 1 ounce'A <br />With a good agricultural surfactant. optimum timing for Escort is similar to Telar. <br />Mechanical Control of Russian Knapneed <br />Russian knapwced tends to form monocultures and usually eliminates other plants. Therefore, sowing <br />desirable plant species is necessary after the weed is controlled. Smooth brume will compete %vith Russian <br />knapwced. Research shows that streambank a heatgrass, thickspikc whcatgrass, crested N\ heatgrass and <br />Russian wlldryc established after Russian knapweed was suppressed with herbicides. Sod-forming <br />perennial grasses, like streambank or thickspike wheatgrasses, help prevent reinvasion better than hunch <br />grasses like crested wheatgrass. <br />If the Russian knapwced stand is not too old and grasses are still present, stimulating grass growth by <br />irrigation (where possible) should increase grass competition with knapwced and keep the weed under <br />continual stress. <br />Spotted knapweed