|
|
MUSK THISTLE
Musk thistle is an aggressive biennial or winter annual that reproduces by seed. This plant is found in pastures, rangeland, and forests, roadsides, and waste areas. This noxious weed competes well with desirable forages and native vegetation.
Control
Since Musk thistle reproduces by seed, the key to success is to prevent seed production. Mechanical: This plant cannot tolerate tillage; therefore, it is not considered a problem in most crops. It can be removed easily by cutting through its roots below ground with a shovel or hoe. Mowing will reduce seed production and is most effective when the terminal head is at the early bud stage. It is recommended to gather and burn mowed or picked debris if possible. This is especially true if digging or mowing was done during the late flower stage.
Biological: Insects have been used to suppress populations, but will not eradicate them. Rhinocyllus conius can be found in dense patches throughout Idaho. This weevil is known to reduce seed production as much as 50%. The use of this weevil alone is not very effective.
Herbicide: Herbicide control of this weed is best during the first year of growth or during the rosette stage; although it can be applied from bolt to early flower. This department has seen good results in rangeland, pastures, and other non-crop areas by applying products containing clopyralid, metsulfuron, chlorsulfuron, picloram, or dicamba. Picloram is a "restricted use" product and can only be applied by a licensed applicator.
When choosing any kind of control method, assure that your choice is suited for your particular situation. Always read and follow the entire product label before applying any herbicide. |