October 3, 2008

Timing is everything. That's particularly true with thistle control and October to early November is one of the best times to apply herbicides for thistle control.

If you had thistles this year, this is a good time to check your pasture again for thistle seedlings. Most will be small and in a flat, rosette growth form. At this growth stage they are very sensitive to certain herbicides, reducing potential problems next spring when there's less time to deal with them.

Several herbicides are effective and recommendeded for thistle control. A newer herbicide called Milestone may be one of the most effective. Two other effective herbicides are Tordon 22K and Grazon. Be careful with these products though as they also can kill woody plants, including trees you might want to keep. Also, 2,4-D works well while it's warm, but you will get better thistle control by using a little less 2,4-D and adding a small amount of Banvel to the mix. Other herbicides like Redeem, Ally and Curtail also help control thistles in pastures.

No matter which weed killer you use, be sure to read and follow label instructions, and spray on time. Next year, avoid overgrazing pastures so grass stands get thicker and compete with any new thistle seedlings.

Bruce Anderson
Extension Forage Specialist