Over the last two weeks, many of us have agonized over the notion of whether or not we will need to replant any or all, of our corn crop. As each of you take the time to assess your corn crop over the next few days to determine if you are in a replant situation, it’s important to remember that a portion of your replant decision should also focus on controlling the volunteer corn that emerged.
If the initial corn crop you planted was non-GMO or tolerant to Liberty® only, this is very easy. You can either utilize tillage to tear out the existing corn plants or apply a glyphosate herbicide such as Roundup PowerMAX®, or Buccaneer Plus. Remember, non-GMO and LibertyLink® corn are extremely sensitive to glyphosate so 0.75 lb./A. a.e. glyphosate (ex: 22 oz. Roundup PowerMAX) along with an ammonium sulfate source will work well in these situations.
If your initial corn was Roundup Ready only and does not carry the LibertyLink trait, you can utilize tillage or Liberty herbicide to control your first planting of corn. Typically, 32 oz./A. of Liberty along with 3 lb./A. of ammonium sulfate will control emerged Roundup Ready corn up to the V3 or V4 growth stage. When it comes to applying the Liberty herbicide, I’d also suggest using a minimum 15 gal./A. spray volume.
For the majority of our corn, which is tolerant to both Roundup and Liberty herbicides, we’ll have to be more creative. If it fits your system and it’s practical to get machinery to the replant area, tillage is a good option that allows you to replant your corn immediately. I have also included a few herbicide options below with some things to consider when terminating your Roundup Ready or LibertyLink crop.
1. Gramoxone SL 2.0 at 2.5 pt./A.
+ Atrazine 90DF at 0.5 lb./A. or Atrazine 4L at 1 pt./A. + Crop Oil Concentrate at 1 gal./100 gal. spray volume
Minimum spray volume: 20 gal./A.
May only achieve adequate termination of 50 to 70 percent of emerged corn plants due to growing point being below ground prior to V5
No waiting period necessary to replant
2. Select 2EC/Volunteer/Arrow 2EC at 4 oz./A.
+ Crop Oil Concentrate at 1 gal./100 gal. spray volume + AMS at 17 lb./100 gal. spray volume
Minimum spray volume: 15 gal./A.
Will achieve termination of 100 percent of emerged corn plants
Avoid overlap of spray boom passes
Cannot replant corn for six days after treatment
Remember, failing to terminate your initial stand of corn is potentially more detrimental to your yield than a competitive weed. We can control weeds in our corn, but volunteer corn can become a weed that we cannot control.
If you have questions regarding any of the above information, or other agronomic concerns, please do not hesitate to contact myself or your local Beck’s representative for more information.
Luke Schulte | Field Agronomist, CCA
Liberty® and LibertyLink® are registered trademarks of Bayer. Roundup® and PowerMAX® are registered trademarks of Monsanto Technology, LLC.