Southern Spotlight: Controlling Volunteer Corn

James Banahan

James Banahan

Imagine a single kernel of corn rolling around in your hand.  How many of these did you leave in your field at the end of last season?  Of course, you didn’t leave them purposefully.  They ended up on the ground due to head shatter and overfull bins at harvest, due to deer ripping through your fields and knocking the ears from your plants.

However they got there though, they’re back to haunt your soybeans right about now.

We’re talking about controlling volunteer corn.  How many kernels did you leave in fields at the end of last season?  Take a look-see and count the corn plants popping up between the beans and therein lies your answer.  Fortunately, controlling these unwanted volunteers is a relatively painless process.

The volunteer corn problem this year does seem to be worse than usual, but even in a year like this one, it’s easily addressed with products you can tank mix for less than $5 per acre.  If you’re already going out with Roundup, why not tank mix to control all that you can and make the most of the time and money you invest into every pass through your fields?

If you’re thinking, $5 per acre!  For what?  Then you’re of the mind that volunteer corn in your soybeans is a purely cosmetic issue.  Except it isn’t: university data from multiple states (Indiana, Minnesota) indicates that volunteer corn can cause a 1 to 1 ½ bushel yield reduction per acre.  Controlling your volunteer corn now amounts to spending $5 to save $12 come harvest.  It’s an investment that’s quickly recouped.

The benefit to your pocketbook comes up front.  The benefit to your crops comes underground: volunteer corn provides a safe haven for root worm beetles.  Leaving it in the field eliminates one huge benefit of crop rotation, which is to interrupt such pests trying for a foothold in your fields.  Addressing your volunteer corn will eliminate all hosts and ensure that any root worms can’t find a home among your crops.volunteer_corn

An additional danger to leaving volunteer corn in your field is the very real potential of speeding the development of pesticide resistance.  BT is the trait that helps protect corn plants against corn borers.  When you rotate crops, you cut down on the opportunity for corn borers to develop resistance to the BT trait.  Leaving volunteer corn in your fields during a soybean year however undercuts that benefit of crop rotation and gives borers more opportunities to develop their resistance.

Not investing the $4-5 per acre to control volunteer corn right now has consequences in both the short and long term.  The yield reduction that volunteer corn causes will cost you a quick $12 per acre this very season, but the larger cost of leaving volunteer corn will come later via rootworm and pesticide resistance.  I can’t put a cost on those things for you, but I’ll bet my lunch that when their cost is due to be paid, it’ll be more than $12 per acre.

As we enter the thick of our growing season, it’s worth a mention that you can prevent volunteer corn with careful attention to your combine’s settings.  Being attentive to the excellent working order of your combine will prevent head shatter and ensure that as many kernels as possible find their way out of your fields and into your bins.  To leave just three kernels per plant in your field is to leave an entire bushel per acre.  Paying attention to your combine’s settings not only erases the tragedy of leaving a bushel per acre on the ground, but also erases the irritation, annoyance, and overall drag of dealing with unwanted volunteer plants the following season.