Winter annual grasses are typically the most difficult weeds to control in wheat. They are highly competitive with the crop for moisture, nutrients, and light and will quickly reduce yield if not properly controlled early in the growing season.
With the recent rainfall and warm temperatures, winter annual grass weeds will soon be growing and competing with wheat for available moisture and nutrients. Within the next few weeks, it will be necessary to scout each field and answer the following questions.
What weeds are present in each field?
Unfortunately, no single herbicide will control all of the weeds present in each field. Therefore, it is extremely important to properly identify the grasses so that you choose the appropriate herbicide. While many weeds look similar as seedlings, one of the easiest ways to identify a grass weed is to carefully dig the plant up from the soil and look at the seed. I have compiled several photographs of grass weed seedlings and their seeds in a slideshow available at tinyurl.com/grassweedID.
Which herbicide should be used?
Once the grass weeds have been identified, it is crucial to choose a herbicide that will properly control them. Again, no single herbicide will control all weeds in a field. Therefore, it is often necessary to combine herbicides to broaden the spectrum of weeds controlled.
To maximize weed control, always follow the label’s recommendations for use rate, application timing (crop growth stage and weed size), and necessary additives or adjuvants. It is also important to remember that all herbicides work best when applied to actively growing weeds. If a weed is stressed due to extremes in temperature or moisture availability, it will be much more difficult to control with any herbicide.