By Darren Hefty

The most important time to kill weeds in winter wheat is in the fall.  Consider which weeds are the biggest challenges.  It’s the grasses that really give you headaches.  Here is our game plan for wiping out problem grasses and maximizing your yield potential.

Step 1 – Pre-Emerge Herbicide Use

  • While it may be too late for you to get a pre-emerge on this fall, keep an eye on the trials being done in your area.  We’ve seen a good return on investment using pre in wheat with improved weed control and higher yields.
  • For problem grasses, the best choice is Pre-Pare.  It has the same active ingredient as Everest, which is in the ALS family.

Step 2 – Fall Application of Post-Emerge Grass Herbicide

  • Yes, this could be your second application of herbicide if you got the pre down.
  • ALS herbicides like Beyond for Clearfield wheat, PowerFlex, Olympus, and Maverick provide the best control of the toughest winter annual grasses.
  • Cheatgrass, Downy Brome, Japanese Brome, Jointed Goatgrass, and other grasses that get their start in the fall are best controlled in the fall.  If you wait until spring, the grass weeds will have bigger root systems and may have tillered out before you can apply your herbicide resulting in a significantly lower level of weed control.
  • Choose your herbicide option carefully as rotational restrictions apply to all of the herbicides mentioned above.  Generally speaking, the longest rotational restrictions are with Maverick.  Olympus has a little less carryover to future crops, and PowerFlex appears to have the least.  The labels give some good guidelines as to how soon you could safely plant another crop, but if you’re in an area that gets very little rainfall or has soil pH’s outside the 6.3 to 7.3 range you should wait even longer.  Talk to an agronomist for specific recommendations for your area.

Step 3 – Fertility

  • If you didn’t have your fertility program just right before or at planting time, you can still do some foliar feeding especially with P, K, and micronutrients.  Having the right nutrition in your wheat allows it to grow thick and fill in quickly resulting in better winter survival and disease tolerance.
Frequently Asked Questions

Q: What if I don’t get it done in the fall?

A: It will be tougher to kill winter annual grasses in the spring.  Herbicides will offer suppression of weeds rather than complete control which may likely cost you bushels at harvest.

Q: What if the weeds have yet to emerge?

A: When the wind blows and the rains don’t come, the one positive is that the weeds may not germinate.  If you get the rain needed to get the crop growing, the weeds will come.  Using a pre-emerge herbicide is great insurance and costs very little, especially compared to the value of a bushel of wheat.

Q: Will I still need to treat in the spring?

A: Even if you do everything right in the fall, you may still need to spray some escapes in the spring.  If your only fall treatment was a pre-emerge treatment with Pre-Pare, PLAN ON SPRAYING ESCAPES in the spring.  You’ll greatly reduce the weed pressure w which helps get a thicker stand of wheat and also makes it easier to kill the weeds in the spring.