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Biology and Management of the Toadflaxes management plans should integrate as many strategies as possible to increase potential for success. Assess the condition and composition of the existing plant community in an infested area then determine the approximate composition of the desired plant community needed to achieve land management goals and objectives. Create a management plan that combines various control strategies to foster development of the desired plant community. Chemical and Cultural Management of Dalmatian Toadflax Dalmatian toadflax may be controlled with Tordon 22K at 2 pt/A sprayed at flowering or in fall. In Colorado, rates of 2, 4, and 8 pt/A of Tordon were compared and control longevity was greatest from the 2 pt rate, apparently because competition from crested wheatgrass was maintained. Researchers in Wyoming treated Dalmatian toadflax in early September, 1994, with Tordon at 2 pt/A, then seeded the following year in April or August with'Hycrest' crested wheatgrass, 'Luna' pubescent wheatgrass, 'Critana' thickspike wheatgrass, 'Bozoisky' Russian wildrye, or'Sodar' streambank wheatgrass. The combination of spraying and seeding competitive grasses controlled Dalmatian toadFlax better than spraying alone. Three years after treatments were started, control of Dalmatian toadFlax ranged from 61 percent to 86 percent where grasses were seeded in April and from 76 percent to 95 percent from the August seeding, compared to no wntrol from spraying alone. Chemical Control of Yellow Toadflax Page 3 Figure 2: DALMATION TOADFLAX [Linaria dalmatira (L.) Mill. = Linaria genistifolia ssp, dalmatica (L.) Maire & Petitmengin]. Noxious. This differs from yellow toadflax principally in being larger and having differently shaped leaves. Clumps of stems are 3 to 4 feet tall. Waxy leaves are broad, ovate, sometimes heart shaped and upper leaves clasp the stem (an important difference). Seeds are irregular in shape, angular, somewhat flattened, thin- etlged, strongly netted, tan-gray and 1/24 to 1Ji6 inch across. It is not as common, but is more aggressive than yellow toadflax. It is reported in various parts of the Yellow toadflax appears to be more difficult to manage state from 5,000 to e,soo feet. than Dalmatian toadFlax. In Colorado, control from Tordon applied at flowering has been most consistent and typically, 4 pt/A is recommended. Yellow toadFlax usually recovers from a single application. For example, Tordon applied at 4 or 8 pt/A controlled 13 percent and 69 percent of yellow toadFlax three years after treatments were applied. Other research conducted in Colorado suggests that yellow toadflax control may be improved if Tordon is applied over three consecutive years, but control varied with location. In one experiment conducted at high altitude (Camp Hale; elevation approximately 10,000 feet), 4 pt/A of Tordon applied at flowering for three consecutive years decreased shoot density to zero. However, the same treatment applied for three years at two other locations (White River drainage, elevation approximately 8,500 Feet) controlled 69 percent and 35 percent of yellow toadflax. Telar also may be used to control yellow toadFlax in non-crop areas. In an experiment conducted in Middle Park near Parshall, Telar at 1.25 ounce/A applied during flowering or in fall controlled 84 percent of yellow toadFlax one year later. Escort, 2,4-D amine, Banvel, and Paramount controlled from 5 percent to 24 percent of yellow toadFlax one year after single treatments were applied at flowering. Plateau showed some potential to control yellow toadFlax in another Colorado experiment where 8 Fluid ounces per acre applied once in fall controlled 59 percent of yellow toadFlax one year later. While this level of control is unsatisfactory, sequential treatments may increase control but experiments must be conducted to test this hypothesis. 4 http://vvvvw.ext.colostate.edu/pubs/natres/03114.html 6/20/2005