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i <br /> r <br /> Recommended management methods: <br /> Cultural- Establishment of selected, aggressive grasses can be an effective <br /> cultural control of diffuse knapweed. Contact your local CSU Extension office or <br /> Natural Resources Conservation Service office for seed mix recommendations. <br /> Mechanical- Mowing the above-ground portion of the plant,before seed set <br /> may be an effective way to reduce seed production. Mowings should be followed <br /> by a fall herbicide treatment. Pulling can be effective on smaller infestations but <br /> must be done repeatedly. <br /> Biological - Biological control agents, such as the seed head weevil (Larinus <br /> minutus) and the gall-forming fly (Urophora affinis), are two of several species that r <br /> are effective at controlling large infestations. When used together, these insects <br /> provide fair to good control. Expect to wait at least 3 to 5 years for the agents to <br /> establish significant populations and achieve optimum management results. <br /> Biocontrol agents can be obtained at no charge from the Colorado Department of <br /> Agriculture's Insectary. Please call 970-464-7916 or go to <br /> www.palisadeinsectary.com for more information. Diffuse knapweed is more <br /> likely to be grazed by sheep. The plants must be green and succulent and the <br /> only forage available in order for sheep to graze it. <br /> Herbicides- The following are recommendations for herbicides that can be <br /> applied to range and pasturelands. Always read, understand, and follow label <br /> directions. The herbicide label is the LAW! <br /> Herbicide Rate Application Timin Comments <br /> 2,4-D Amine 1 qt./acre Spring/fall rosette—before flowering stalk lengthens.DO NOT <br /> or apply when outside temperatures will exceed 85 degrees. ' <br /> 1 oz/gal water Add non-ionic surfactant @ 0.32 oz/gal water or <br /> 1 t/100 gal water. <br /> Curtail 2 qts./acre Spring rosette to pre-bud stage and/or fall rosette. <br /> or Add non-ionic surfactant @ 0.32 oz/gal water or <br /> 2.0 oz/gal water 1 t/100 gal water. <br /> Clarity 1 qt./acre Spring rosette—before flowering stalk lengthens and/or late fall <br /> or treatment of rosettes.DO NOT apply near or under trees and/or r <br /> 0.75 oz/gal water shrubs or when outside temperatures will exceed 85 degrees. <br /> Milestone 5 to 7 oz/acre Apply to plants in the spring rosette stage and/or to dormant <br /> plants in the fall. If the plants are in the bud stage add 2,4-D at <br /> 32 oz/acre.It is permissible to treat seasonally dry wetlands and <br /> transitional areas between upland and lowland sites.DO NOT <br /> rotate to a broadleaf crop within 1 year of application.Add a <br /> non-ionic surfactant 0.32oz/ al water or 1 t/100 gal water. <br /> Transline 1/3 to 1 1/3 pints/acre Apply after the majority of basal leaves have emerged up to <br /> early bud stage or fall regrowth.A number of trees are tolerant <br /> to the herbicide.Roses and leguminous trees can occasionally <br /> be affected with root uptake.No grazing or haying restrictions. <br /> Add a non-ionic surfactant 0.32oz/ al water or 1 t/100 gal. <br /> The seedhead gall fly, Urophora quadrifasciata, r <br /> is one of many biocontrol agents available for <br /> release to control diffuse knapweed. <br /> 1 <br /> 1 <br />