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Page 5 of 23 Appendix l <br />If a Canada thistle infestation exists in a field that will be rotated to alfalfa, control the weed before seeding <br />alfalfa. Alfalfa is an effective competitor only after it is established. It will not adequately establish in a <br />well-developed Canada thistle infestation. A Canada thistle management system can start with crop or grass <br />competition combined with herbiades, with the field rotated to alfalfa when the management plan ends. <br />Musk thistle <br />Management <br />Cultural control of Musk Thisdc <br />Maintaining pastures and rangeland in good condition is a primary factor for musk thistle management. To <br />favor pasture and rangeland grass growth, do not overgraze. Fertilize only when necessary and according to <br />soil testing recommendations. To successfully manage musk thistle, prevent seed formation. <br />Mechanical control of Musk Thistle <br />Musk thistle will not tolerate tillage and can be removed easily by severing its root below ground with a <br />shovel or hce. Mowing can effectively reduce seed output if plants are cut when the terminal head is in the <br />late-flowering stage. Gather and burn mowed debris to destroy any seed that has developed. <br />Chemical Control of Musk Thistle <br />Several herbicides are registered in pasture, rangeland and noncrop areas to control musk thistle. Tordon <br />22K (picloram), Curtail (clopyralid +2,4-D), BanvelNanquish/Clarity (dicamba), 2,4-D, or <br />BanvelNanquish/Clarity plus 2,4-D are commonly used. Apply these herbicides in spring or fall to musk <br />thistle rosettes. <br />Apply Tordon at 0.5 to l pint per acre (A), Curtail at 2 quarts/A, BanvelNanquish/Clarity at 0.5 to 2 <br />quarts/A, 2,4-D at 1.5 to 2 quarts/A, or BanvelNanquish/Clarity plus 2,4-D at 0.5 plus I quart/A. Cool <br />temperatures (below 50 degrees F), particularly in fall, may adversely affect 2,4-D control of musk thistle; <br />therefore, use 2,4-D in spring. Tordon is largely unaffected by cool temperatures. BanvelNanquish/Clarity <br />can be adversely affected but less than 2,4-D. BanvelNanquish/Clarity plus 2,4-D works well in spring or <br />fall. Apply any of these herbicides before musk thistle bolts or seed production still will excur. <br />