Cooperative
Extension
Service


University of Illinois
at
Urbana-Champaign


No. 9/May 21, 1998

Corn Replanting and Herbicide Selection
--A Reminder

Numerous corn fields across much of Illinois have less than ideal stands. Many of these stand problems are confined to the "perennial wet holes," but others encompass a large part of the entire field. With many of these areas scheduled for replanting, hybrid selection the second time around may influence a producer's weed control options. In particular, some fieldsinitially planted with a particular herbicide-resistant/tolerant corn hybrid likely will have areas to be replanted. If the field was treated with a soil-applied herbicide that requires a particular resistant/tolerant corn hybrid, any areas replanted in these fields should be replanted with the same or a similar resistant/tolerant corn hybrid. If a nonresistant/ tolerant hybrid is replanted instead, the potential exists for the herbicide to cause a great deal of crop injury.

What if no herbicide has yet been applied? Several possible scenarios exist.

  1. If the entire field is to be treated with the herbicide initially planned for use requiring a resistant/tolerant hybrid, the replanted area should be replanted with the same or a similar hybrid, or else severe injury likely will result to the replanted area.

  2. If the producer still wants to utilize the herbicide initially planned for use that requires a resistant/tolerant hybrid, but the same or similar hybrid is not available for replanting, then the replanted area should not be treated with this herbicide. The replanted area should be marked in some way so that it is not treated with the herbicide used on the rest of the field. A different herbicide that does not require a resistant/tolerant corn hybrid could be used to treat the replanted area.

  3. If the same or similar hybrid is not available for replanting, the option may exist to use a different postemergence herbicide that does not require a resistant/tolerant corn hybrid.

Although the focus of this article centers on corn, the same general principles hold should soybean replanting occur.

Aaron Hager (hagera@idea.ag.uiuc.edu) and Marshal McGlamery (mmcglame@ uiuc.edu), Department of Crop Sciences, (217)333-4424