Replanting corn? Knock down old stand first
A lot of corn acres have faced freezing temperatures since they were planted. Some were salvaged, but others may have gotten knocked out. So, now what?
Replant's inevitable in some cases, but just make sure those earlier-planted seeds aren't going to spring back to life later on and cause problems. To ensure a uniform stand later on in the growing season, take steps now to knock them down before you replant, advises University of Illinois weed scientist Aaron Hager.
"While the damage appears not to be widespread, it is very likely that some growers will opt to replant damaged stands," he says. "Glyphosate is very effective for controlling existing stands of corn hybrids sensitive to glyphosate.”
But, you may have planted glyphosate-resistant seed. If that's the case, read the label carefully, and if your hybrid has the right sensitivity, any herbicide containing paraquat and glufosinate can typically work where glyphosate may not be able to, Hager says, but they're not always a sure thing. "Previous research with these herbicides has demonstrated that complete control is not always achieved," he says.
Hager advises looking into using these products along with a combination of atrazine or metribuzin. If you use these products, you may see a side benefit, too. "Paraquat and glufosinate would also control a broad spectrum of emerged weeds," he adds.
If you're burning down existing corn plants in order to replant, most products, namely glyphosate, could benefit from a 24-hour wait period before replanting. But, if you're in a rush, Hager says you can usually replant immediately after glyphosate application, for example.