After starting the season with clean fields at planting, now is the time to focus on early season weed control to maintain maximum yield potential. For corn, weeds can reduce yield as soon as the V2 stage or when corn is roughly six to eight inches tall. Focus on weed control prior to the V2 stage and maintain control through at least the V14 stage. In soybeans, control weeds during the first four weeks and maintain control through canopy closure.
Sequential weed control programs, including preplant and preemergence (PRE) followed by postemergence herbicides, have consistently provided the best weed control and greatest net returns. If you did not apply preplant or PRE herbicides, Dave Johnson, DuPont Pioneer senior research scientist recommends the following management tips:
- Apply postemergence herbicides as soon as possible.
- Extend control of weeds that are still germinating with the use of residual herbicides.
- Use the recommended rate for the weed size; do not cut the use rate.
- Use high-quality adjuvants as directed on the product labels.
- Apply follow-up treatments as needed to control escapes and late-germinating weeds.