 Yellow starthistle is a winter annual, maturing from 2 to 72 inches tall. It spreads exclusively by seed, which may lie dormant for as long as 10 years. Yellow starthistle poisoning has occurred in horses as well as in other laboratory test animals. Effects may be first noticed as abnormalities in walking or other movement. In rangeland, yellow starthistle is very competitive, forming solid stands that drastically reduce and frequently eliminate forage production and grazing capacity ControlControl of yellow starthistle is most effective by using an integrated approach. You can enact suppression by planting desirable species.Mechanical: Mowing can be used to manage yellow starthistle, provided its done frequently and before the flower stage. Cultural: Control practices are capable of reducing yellow starthistle populations, but in the absence of competition, starthistle will re-establish. Species choice for re-vegetation will depend on the intended use of the site. Biological: Five natural enemies of yellow starthistle have been imported from Europe and are well established. They all attack the flower/seed head reducing seed production. The seed head weevils are: Bangasternus orientalis, Eustenopus villosus, and Larinus curtus. The seed head flies available are: Chaetorellia australis and Chaetorelia succinea. Grazing is effective in reducing yellow starthistle seed production. Sheep, goats, or cattle eat yellow starthistle before spines form on the plant. Goats are able to eat the spines. Chemical: Although several products have demonstrated good control, picloram is generally the most effective herbicide. Picloram is a "Restricted Use" chemical and must be applied by a licensed applicator. This product is effective in rangeland, pastures, roadsides and other non-crop areas When choosing any kind of control method, assure that your choice is suited for your particular situation. Always read and follow the product label before applying any herbicide. | |