Proper pasture management is the key to avoiding weed problems. A healthy pasture will effectively compete with most weeds. When weeds become a problem, typically the pasture has a fertility problem or has been subjected to poor grazing strategies. If these factors are corrected, the weed problem will be significantly lessened. Herbicides may have a role in pasture weed management but can not resolve poor cultural practices.

Biennial thistles are common weeds in pastures. Best control of these weeds is obtained when the herbicide is applied while the thistle is in the rosette stage. Once the plant bolts (initiates the flower stalk) herbicidal control is more difficult. Bull and tall thistles can be controlled with 2,4-D applied at 1 to 1.5 qts/A while musk thistle will typically require 1.5 to 2 qts/A. A combination of 1 qt/A 2,4-D plus 0.5 pt/A Banvel may provide better control of thistles, particularly if the application has been delayed until bolting occurs.

                                        Interval between
Herbicide          Type of Animal     application & grazing    Comments

2,4-D amine           Dairy                 14 days            2,4-D labels vary.
                      Other              No restriction        See specific label.
2,4-D ester            All                   7 days            2,4-D labels vary.
                                                               See specific label.
Ally                   All               No restriction
Banvel            Lactating dairy        7 days if < 1pt.