Musk Thistle
One reason musk thistle is considered invasive is its incredible reproductive rate. A single flower head may produce 1,200 seeds, and a single plant with several plant heads up to 120,000 seeds, which may be wind blown for miles. Seed may remain viable in the soil for over ten years, making it a difficult plant to control.
Musk thistle infest the following areas:
Musk thistle is a biennial weed that reproduces only from seed (it is an annual in cooler climates). Mature plants range in height from 1-1/2 feet to 6 feet tall and they have multi-branched stems. Musk thistle is unpalatable to wildlife and livestock and crowds out other plants animals might graze on. BACKGROUND
Musk Thistle is a native of western Europe and was introduced into the eastern United States in the early 1800s. It has a long history as a rangeland pest in the U.S., was first discovered in Davidson County, Tennessee in 1942, and has been declared a noxious weed in many states. 
Musk Thistle Control
Mechanical control - Musk thistle will not tolerate tillage and can be removed easily by severing its root below ground with a shovel or hoe. Mowing can effectively reduce seed output if plants are cut when the terminal head is in the late-flowering stage.
Cultural control - Maintaining pastures and rangeland in good condition is a primary factor for musk thistle management. To favor pasture and rangeland grass growth, do not overgraze.
Chemical control - Several herbicides are registered in pasture, rangeland and non-crop areas to control musk thistle.
Biological - Two weevils have been introduced from Europe and released in the United States as a biological control for musk thistle, the thistlehead-feeding weevil and the rosette weevil. These weevils have been released in a number of western states with some notable successes achieved. However, recent observations of unintentional and unanticipated impacts of the thistlehead-feeding weevil to native thistles, including some rare species.
Note: The single best way to control Musk Thistle is to control seed production since this is how they spread and grow. |