By Mike Owen, Department of Agronomy
The recent deluge of water has destroyed many corn fields and if the previously applied herbicide requires that corn be replanted, how do you kill the existing poor stand?
If the corn hybrid was a known herbicide resistant cultivar, your options are somewhat limited. If the hybrid was Roundup Ready®, the use of Liberty® or paraquat are not likely to consistently control the emerged corn.
If on the other hand, the cultivar was not Roundup Ready®, you have an excellent option with the use of glyphosate. Recognize that some corn hybrids are genetically engineered to be resistant to both glyphosate and Liberty®. It is suggested that you check with the seed company to make sure the hybrid you have is not resistant to multiple herbicides.
In these cases, where the hybrid is a Roundup Ready® cultivar or a hybrid with multiple herbicide resistance, you are limited to tillage or the use of Select Max®. Select Max® has a supplemental label for control of corn in replant situations, but requires a 6 day interval between application and replanting corn.
Before you consider replanting to soybeans (control of existing corn stand is still a problem), it is imperative that you determine that a previously applied corn herbicide(s) does not restrict replanting options.
Mike Owen is a professor of agronomy with research and extension responsibilities in weed management and herbicide use.
This article was published originally on 6/1/2008 The information contained within the article may or may not be up to date depending on when you are accessing the information.
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