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Page 1 0 of 23 <br />Russian knapweed <br />r t <br />V1 <br /> <br />?tana yenienI <br />\ppendix I <br />Like other creeping perennials. the key to Russian knapwced control is to stress the weed and cause it to <br />upend nutrient stores in its root system. An integrated management plan should be developed that places <br />contnntal stress on the weed. Currently, the hest management plan includes cultural control contbinal with <br />mechanical an(Lor chemical control techniques. A single control strategv, such as mowing or a herbicide, <br />usually is not sufficient. <br />Russian knapwced typically invades degraded arras, dominating the plant coninutttity and desirable plants <br />(e.g. perennial grasses). Seeding competitive. perennial grass species (cultural control) after Russian <br />knapwced has been stressed by other control measures (set-up treatments) is essential. Sct-up treatments <br />may include chemical or mechanical methods. <br />Cooperative research between Colorado State University and the University of Wyoming showed that <br />chemical set-up treatments were superior to mowing. Curtail (clopyralid + ?.4-1)). Escort (metsulfuron), <br />and Roundup (glyphosatc) were used to suppress Russian knapwced. Then Perennial grasses \% ere sown in <br />late fall as a dormant seeding. Tillage is necessary to overcome the residual allclopathic effects of Russian <br />knapwced. Curtail (3 quarts per acre) (A) or Escort ( I Mince, A) were applied at the bud-growth stage. <br />Roundup was applied twice at I quart'A, first at the bud-growth stage and again about R ?r eks later. <br />Curtail controlled Russian knapwced hest, but Roundup failed TO control it. <br />None of the herbicides injured seeded Grasses. Grasses established similarly among herbicide suppression <br />treatments, even though Russian knapwced control varied. I lowcver, where Escort or Roundup was used to <br />suppress Russian knap\keed. additional herbicide treatments would be necessary to achieve acceptable <br />control. <br />While two ntowings, eight weeks apart (first at bud-Growth stage), suppressed Russian knapwced during <br />that year, the cared recovered vigorously the subsequent season. Perennial grasses established in the <br />nxnving treatments but much less than in herbicide treatments. "Iwo nwwings per year Ior several wars <br />may control Russian knapwced better, but further research is needed to test this hypothesis. Currently, no <br />biological control is available for this weed.