Spring is here and it’s time to get moving. While planting corn and soybeans is in the front of everyone’s mind, for those who planted wheat in the fall, it’s now time to do some maintenance. There are fertilizer applications to jumpstart growth, and equally important, herbicide applications to cut down on competition, and let your wheat take hold of every available resource.
Winter annual weeds may not have been noticeable before, but they can start to take off if left unchecked. Timely scouting is a vital part of getting weeds under control. A good threshold for winter weeds in wheat is 1 broadleaf or 3 grass weeds per square foot. As with any weed management plan, the earlier you can take care of them, the better your control will be.
Some common winter broadleaf weeds to be on the lookout for include dandelion, mustard, henbit, chickweed, and shepherd’s purse. Grasses may also be present, such as annual bluegrass, annual rye, cheat, Italian ryegrass and downy brome. If stands are thin or wheat development has been slow, you may also need to keep an eye out for early germinating summer annuals, such as kochia, Russian thistle and wild buckwheat.
What you can spray is primarily determined by the weeds you find and the stage of your crop. Most wheat herbicides do their best work when weeds are still in the rosette stage and will lessen control once wheat starts to develop a canopy.
The majority of wheat herbicides are labeled for specific growth stages and some have short application windows. For example, 2,4-D and MCPA can only be applied between tillering and before jointing. Once the boot stage is reached, your options for weed control in wheat are limited.
Another consideration when selecting an herbicide for your wheat crop is the plantback interval to the next crop. Herbicides such as Huskie®, and Starane NXT® have residual weed control, but because of this, they also have crop rotation restrictions. Check the crop rotation restrictions before applying any herbicide, especially if you plan to double crop soybeans after your wheat.
In some cases, you may find that you can make one pass for both your herbicide and fertilizer, using a liquid nitrogen solution as a carrier for the herbicide. Be sure to use caution, though, as this can increase your chances of crop injury.
Also remember to always read and follow all herbicide label instructions because use of a liquid nitrogen carrier may impact herbicide use rates and adjuvant requirements.
Sources:
HUSKIE is a registered trademark of Bayer. Starane is a registered trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow.