Laserfiche WebLink
Page 1 0 o f <br />Russian knapweed <br /> <br />Management <br />Appendix 1 <br />Like other creeping perennials, the key to Russian knapwecd control is to stress the weed and cause it to <br />expend nutrient stores in its root system. An integrated management plan should be developed that places <br />continual stress on the weed. Currently, the hest management plan includes cultural control combined aith <br />mechanical an&or chemical control techniques. A single control stratcgv, such as nuowing ur'a herhtcidc, <br />usualty is not sufficient. <br />Russian knapwecd typically invades degraded areas, dominating the plant community and desirable plants <br />(e.g. perennial grasses). Seeding competitive, perennial grass species (cultural control) after Russian <br />knapweed has been stressed by other control measures (set-up treatments) is essential. Set-up treatments <br />may include chemical or mechanical methods. <br />C'oopcrahve research between Colorado State I'nivcrsity and the University of Wyoming showed that <br />chemical set-up treatments were superior to nimving. Curtail (clopyralid + 2.4-1)). Escort (metsulfuron), <br />and Roundup (glyphosate) were used to suppress Kussian knapwecd. Then perennial grasses ?tere sown in <br />late trill as a dormant seeding. Tillage is necessary to overcome the residual allelopathic effects of Russian <br />knalmeed. Curtail (3 quarts pcr acre) (A) or Escort ( I ounceiA) were applied at the hud-&qomh stage. <br />Roundup was applied twice at I quarVA, first at the bud-growth stage and again about K weeks later. <br />Curtail controlled Russian knapweed best, 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 knapweed control varied. I lowever, where Escort or Roundup was used to <br />suppress Russian knapweed, additional herbicide treatments would be necessary to achieve acceptable <br />control. <br />While two mowings, eight weeks apart (first at bud-gro\4th stage), suppressed Russian knapweed during <br />that year, the weed recovered vigorously the subsequent season. Perennial grasses established in the <br />mowing treatments but much less than in herbicide treatments. Two mowings per year for several years <br />may control Russian knapweed better, but further research is needed to test this hypothesis. Currently, no <br />biological control is available for this weed.