Thistle Control During October

Thistle Control During October September 21, 2016

It’s thistle time again. Even if they are hard to see, this is the time to control them.

crown rot in corn
Figure 1. Large thistle rosette. (Photo by Debalin Sarangi)

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

Did you have thistles this year? If so, walk out in those infected areas this week. Look close. I'll bet you find many thistle seedlings. Most thistle seedlings this fall will be small, in a flat, rosette growth form, and very sensitive to certain herbicides.

Several newer herbicides like ForeFront, Milestone, and Chaparral work well for thistle control. Two other very effective herbicides are Tordon 22K and Grazon. Be careful with all these herbicides, but especially Tordon and Grazon, since they also can kill woody plants, including trees you might want to keep. Another option is 2,4-D, which works well while it’s warm; however, you will get better thistle control by using a little less 2,4-D and adding a small amount of Banvel or dicamba to the mix.

Other herbicides like Redeem, Cimarron, and Curtail also can control thistles in pastures.

No matter which weed killer you use, be sure to read and follow label instructions and spray on time to assure cleaner pastures next spring.

Next year, avoid overgrazing your pastures so your grass stands get thicker and compete with any new weeds or thistle seedlings.