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APPENDIX C <br />INTEGRATED PEST MANAGEMENT OPTIONS <br />Canada thistle (Cirsiunt araense): Canada thistle is an aggressive, creeping perennial <br />that reproduces by seed and vegetative buds in the root system. It is a difficult plant <br />to control because of its extensive, rhizomatous root system. <br />1. Control Measures <br />a) Cultural Control: Plant competition from various grasses can be a very <br />effective management tool. Revegetation with aggressive desirable <br />perennials in disturbed areas can assist in preventing an infestation. <br />b) Mechanical Control: Mechanical control can be accomplished by <br />mowing at least every 14 days throughout the summer. This will <br />prevent seed production, but mowing may stimulate new shoot <br />growth from the spreading roots resulting in a more dense stand than <br />before. <br />c) Biological Control: There are two insect species registered for use in <br />Colorado that have shown some control in the spread of Canada thistle <br />including Ceutorhynchus litura and Urophora cardui.. Both of these <br />species may be available only on a very limited basis. <br />d) Chemical Control: There are numerous herbicides labeled for use on <br />Canada thistle. The selection of a herbicide depends on the area of <br />infestation. Some herbicides that can be used independently or in <br />combination according to EPA recommendations are picloram (Tordon <br />22K), dicamba (Banvel(+2,4-D)), 2,4-D (Weedpro #6 Lovol), glyphosate <br />(Roundup, Rodeo), chlorsulfuron (Telar), metsulfuron (Escort), <br />clopyralid (Transline ,Stinger), clopyralid (Curtail (+2,4-D)) or any <br />other EPA approved chemicals. Rodeo is approved for aquatic use and <br />can be applied directly over the water. <br />Diffuse knapweed (Cenfaurea diffusa): Diffuse knapweed is a biennial to short lived <br />perennial that reproduces by seed. It spreads rapidly when the mature plants break <br />off at the ground and are blown around, thus dispersing seed. It will readily invade <br />dry disturbed sites. <br />1. Control Measures <br />a) Cultural Control: Revegetation with aggressive desirable perennials in <br />disturbed areas can assist in controlling the spread of the plant. <br />However, seeding as the only control method will not contain or <br />control the invasion. <br />b) Mechanical Control: The reduction of seed production by mowing the <br />plant before flowering can reduce the number of seeds produced. If <br />seed production is limited then eradication may be possible by <br />depleting the seed bank in the soil. <br />