Judging from recent conversations there will be a significant number of corn acres that will need to be replanted. The long cold and wet spell apparently has greatly hindered getting a good stand in some corn fields. Fortunately, there are several options to control a thin corn stand and replant back to corn.
The options, like Select Max, need a waiting period before it can be planted back to corn. Others, like tankmixes of paraquat plus atrazine, allow corn to be replanted right away. Please find attached the results of a study Angela McClure and I conducted on destroying freeze damaged corn and replanting back to corn. We repeated the study the following year on a good stand of corn and got similar results. In this publication (Replanting corn in a failed corn stand) you will find a number of different herbicide options that did a good job controlling an unwanted stand of corn.
Many over the past decade have used the recommendations to satisfactory results. The most consistent time to control an old corn stand is around the V2 corn growth stage, which was the timing the research was conducted. Our experience has been over the years that once the old corn stand matures past V2, results from the herbicides in the publication will likely be more sketchy. In those cases, consider using higher rates of the herbicides in the publication to improve the chance for good control.