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Department of Road & Bridge Ken Haynes • Road Superintendent Division of Natural Resources Jennifer Scott, Division Foreman 469 E.Topaz,PO Box 9,Granby,CO 80446 Office: 970-887-0745 • Fax: 970-887-8862 September 9, 2014 Dawna Heller Dear Ms. Heller: After the site visit to the Yust pit on August 27, 2014; here is the information you requested. Colorado listed Noxious Weeds currently present on the property: Musk thistle; Canada thistle; Common mullein. These weeds are present in small quantity at this time and most are at the entrance near the scale and in the disturbed area above the active pit. Information about these species and the best methods of control are as follows: Musk thistle: A biennial weed. Biennial refers to a 2 year life cycle,the first year being vegetative only and the second year the plant finishes its life cycle by flowering, seeding and then dying. Easiest to control in the first year/stage (vegetative, rosette)prior to flower and seed set. • Cultural: Maintaining healthy,vigorous stands of desirable vegetation works very well to keep these species at bay. • Mechanical: These species do not spread by root and thus are readily controlled by hand pulling, cutting or mowing, but note of caution: if cut after bolting,plants can and will resprout it's flowering stem and can still go to seed if the flower is left behind. • Biological: For Musk and Plumeless thistles there are seed head weevils and crown weevils that are effective for control in other areas of CO. There were releases in Grand County in the early 2000's, but the insects were not able to overwinter here and died out. • Chemical: There are several herbicides on the market that are suitable for these species. Grand County Division of Natural Resources (DNR)recommends using Milestone Specialty at a rate of 5 to 7 oz per acre applied at any life stage up to flowering.