When frost temperatures below 26-28oF occur, wait at least 24 hours to evaluate foliage. Herbicides cannot translocate if the weed is dead. Apply herbicides when temperatures are expected to exceed 60-65oF during the day to ensure active translocation. Select the correct herbicide that fits the crop rotation sequence. Use the highest rate labeled.
Some herbicides have crop rotation restrictions and one needs to pay close attention to the label.
Perennial weed control will be the greatest if the field has not been tilled prior to the herbicide application. Mowing perennial weeds in pastures, roadsides, and CRP earlier in the season will enhance the weeds to produce new shoots. This will allow a good setup for a chemical treatment later in the fall. Perennial weed control is enhanced by tillage after a herbicide application. However, one must plan to allow 2 to 4 weeks time to pass after herbicide application to get the full impact of the chemical.