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CANADA THISTLE
Canada thistle is a creeping perennial that reproduces by creeping root as well as seed. It is one of the most prevalent noxious weeds and can be found in all of Idaho's 44 Counties. This noxious weed is highly competitive with crops and can also be found in pastures, rangelands, forests, and along roadsides, ditches, and riverbanks.
Control
The single most important advice in controlling Canada thistle is, Be Persistence! Cultural: Grasses and alfalfa can be effective in competing with Canada thistle. It is important to maintain fertility and moisture. Be aware that competition alone will not be effective.
Mechanical: Mowing can be effective, if it is done every two weeks for several seasons. Tillage will break up roots and stimulate new plants, so unless you plan to use herbicide or conduct cultivation practices every two weeks, be prepared for the infestation to increase in size.
Biological: Ceutorhynchus litura is a stem weevil. Larius Planus is a bud weevil. Biological controls are more effective in secluded areas with low traffic.
Chemical: This department has seen good results in rangeland, pastures, and other non-crop areas by applying products containing clopyralid, metsulfuron, picloram, or dicamba at bud to bloom stage or in early fall. 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. |