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Additional Diffuse Knapweed Non-Chemical Control Information <br /> Diffuse knapweed response to treatments may be impacted by environmental conditions <br /> and the type of treatment utilized. <br /> Grazing control: Diffuse knapweed seed production can be reduced <br /> when grazed during the bolting stage for 10 days, wait 14 days then <br /> graze for an additional 10 days. Although grazing diffuse knapweed <br /> can reduce seed production, grazing can also cause diffuse <br /> knapweed to become a short-lived perennial. When grazing is <br /> stopped,populations often return to their former levels. <br /> Pulling or Digging: Pulling or digging requires a commitment of at least 12 years to <br /> ' ensure that removal of new seedlings and re-growth is done before they reestablish. Years <br /> one to three of a pulling or digging program will involve intensive removal. During <br /> year's four to six,there should be a decrease in diffuse knapweed numbers and the work <br /> will be noticeably easier. Pulling or digging of diffuse knapweed is best done in the <br /> spring during the rosette or early bud stage, before the flowers appear. Hopefully,the <br /> soils will be moist to allow for easier removal. The roots can extend a few feet into the <br /> soil. It is important to pull or dig up the entire taproot. Otherwise, the diffuse knapweed <br /> may re-grow. Keep in mind that some workers may suffer from allergic reactions while <br /> touching diffuse knapweed and inhaling pollen. <br /> Mowing: Diffuse knapweed is persistent. Mowing leaves part of the plant untouched. <br /> This part of the plant will still produce flowers. The plant will just be shorter than the <br /> mower height and will act more like a perennial plant than a biennial plant. In some <br /> cases, diffuse knapweed densities may increase after a single mowing. <br /> ' Burning or Flaming:Normal fires are typically not long enough or hot enough to destroy <br /> diffuse knapweed seeds. A monitored controlled burn can potentially help control diffuse <br /> knapweed if the fire has adequate intensity. It is not easy to find good fuel circumstances <br /> to carry a continuous fire that will cause significant injury to the diffuse knapweed <br /> without hurting the beneficial vegetation occurring in the infestation. Diffuse knapweed <br /> is not very flammable and most areas do not contain <br /> t <br /> enough fuel necessary for the fire. This results in low <br /> a` " temperature fires with patchy and irregular burns. Even if <br /> the surface area of the plant is killed, diffuse knapweed <br /> P p <br /> can often re-grow from its root reserves. <br /> A propane-fueled weed burner can be utilized to quickly <br /> ' burn the foliage of young diffuse knapweed rosettes. The <br /> flame sears the plant, raises the temperature of the cells, <br /> this causes the cells to rupture. The diffuse knapweed <br /> plant will then dehydrate and expire within a few hours. Flaming is done on green plants; <br /> not on dead foliage. Plants can be seared at any time before flowering. Flaming can be <br /> useful in clearing small areas. <br />