Post-emergence Corn and Soybean Herbicide Restrictions for Broadcast Applications

Rodrigo Werle, University of Wisconsin-Madison Cropping Systems Weed Scientist and Extension Specialist

Favorable spring weather has given Wisconsin farmers a great start to the season with a fair amount of corn and soybean acres planted already. The recent trend in warmer temperatures will also lead to weed germination and emergence. However, the lack of significant rain events over recent weeks has left fields that had PRE-emergence herbicides applied without the moisture necessary for activation. This will likely result in weed escapes and place additional pressure on POST-emergence herbicides. In anticipation for heavy reliance on early POST applications to control troublesome weeds in corn and soybean, the Cropping Systems Weed Science program put together a handy guide for over-the-top broadcast application windows of commonly used POST herbicides in corn and soybean.

The application window tables (CLICK HERE TO DOWNLOAD; Table 1 – Corn, Table 2 – Soybean) were generated based on information obtained from each of the product’s label. For additional information on recommended adjuvants and tank mix partners consult individual product labels and/or your local agronomist.

When selecting a POST herbicide program, it is important to consider the weed species present, weed height, and crop growth and/or height.

Inclusion of specific products does not constitute a recommendation or endorsement. Always read, follow, and understand the pesticide label. The label is the law.

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