Content ID


SPONSORED: Scout, Identify and Plan to Contain Resistant Weeds

Use a program approach featuring multiple herbicide modes of action

Scouting fields from the combine cab can help you make profitable decisions for next year. One thing you can do is take note of weed escapes to update weed management plans. Weeds such as waterhemp, marestail, giant ragweed, Palmer amaranth and others may require a shift in your herbicide program to improve weed control and limit the opportunities for these weeds to develop resistance to effective herbicides.

One valuable practice any farmer can adopt is to use a program approach that allows you to take advantage of multiple herbicide modes of action. This not only helps control tough weeds during the current year but also curbs opportunities for weeds to develop resistance. The goal is to apply multiple herbicide modes of action during the growing season. Any weeds that are resistant to one mode of action can be controlled by one or more other modes of action.

When you develop a weed management program, remember that residual herbicides can be extremely valuable. They help control weeds early in the season. This allows the crop to get off to a good start, which is critical to preserving more of the crop’s yield potential. 

In addition, residual herbicides set the stage for the use of multiple modes of action. Farmers can follow residual treatments with effective postemergence applications of herbicides. For example, if you’re planting Enlist™ crops, you can apply Enlist Duo® herbicide — which offers two modes of action — or Enlist One™ herbicide in combination with one of many qualified tank-mix partners.   

Whatever herbicide you’re spraying, it’s important to target weeds when they’re small. Obviously, the longer a weed is in the field, the more resources — such as water and soil nutrients — that weed is taking from the crop. In addition, larger weeds are more difficult to eradicate. Even the most effective herbicides are more successful when farmers can target weeds before they grow too large.

You also need to scout fields regularly all season long and watch for weed escapes. Weeds that remain in the field may have survived because the herbicide somehow didn’t reach them. However, in many cases, they could be resistant weeds that survive even though the herbicide did hit them.

Resistant weeds often appear as patches in fields. Identifying these areas early helps prevent widespread distribution of seeds from the resistant population. If live weeds are growing next to dead weeds and they are of similar size, the surviving weeds may be resistant to the herbicide used in the field.

When you identify resistant weeds, try to control them as quickly as possible. It’s best to get a handle on resistant weeds before harvest. If you run resistant weeds through the combine, seeds may spread across a larger area of the field. This means more resistant weeds may appear in the field in subsequent years.

If you identify resistant weeds, you can begin to develop a herbicide management plan for the next year. Choose effective herbicides or combinations of herbicides that include different modes of action. This can stop these resistant weeds before they gain any momentum.

The Enlist weed control system offers an option to help curb the spread of resistant weeds. Find out more about how it allows you to bring multiple herbicide modes of action into the field to control resistant weeds at Also visit the YouTube channel and follow on Twitter at @EnlistOnline.

Read more about

Crop Talk