Laserfiche WebLink
c) Biological Control: There are two species of knapweed seed head gall <br />flies that are well established in Colorado. These species are Urophora <br />affinis mid U. quadrifascrnta. Seven other insect and fungus species are <br />registered but in limited supply. <br />d) Chemical Control: There are numerous herbicides labeled for use nn <br />Diffuse knapweed. 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), clopyralid <br />(Transline, Stinger), clopyralid (Curtail (+2,4-D)) or any other EPA <br />approved chemicals. <br />Hoary cress/Whitetop (Cardaria draba): Whitetop is a perennial with an extensive <br />vertical and horizontal root system. It flowers early and reproduces by seeds, root <br />stocks and creeping roots. Control is difficult and requires persistent effort. <br />Whitetop prefers areas lacking in plant competition (ie., overgrazed and disturbed <br />areas}, <br />1. Control Measures <br />a) Cultural Control: Plant competition from various grasses can be an <br />effective management tool. Revegetation with aggressive desirable <br />perennials in disturbed areas can assist in controlling an infestation. <br />b) Mechanical Control: Mechanical control can be accomplished by <br />cultivation of the seedlings. The only other effective method is <br />physical removal by hand pulling. <br />c) Biological Control: No biological control techniques are currently <br />approved for Whitetop. <br />d) Chemical Control: There are numerous herbicides labeled for use on <br />Whitetop. 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 chlorsulfuron <br />(Telar), metsulfuron (Escort), and 2,4-D (Weedpro #6 Lovol) or any <br />other EPA approved chemicals. <br />