University of Minnesota Extension

Extension is expanding its online education and resources while in-person events and classes are canceled.

Extension > Extension in your Community > Rice > County Agriculture Educator > Articles > Prepare to address volunteer corn in fields hit by 2018 tornadoes

print icon email icon share icon

Prepare to address volunteer corn in fields hit by 2018 tornadoes

Aside from volunteer labor perhaps, farmers typically do not welcome “volunteers” in their fields. Volunteer corn, or other crops that you hear nicknamed with the “volunteer” prefix, are essentially weeds; corn left out in the field from 2018 will grow in places you don’t want it this year. The downed corn left in the aftermath of the 2018 tornadoes causes a high potential for the occurrence of volunteer corn in these areas in 2019. I wrote an article about volunteer corn last fall, but as farmers are preparing for planting, I wanted to address the topic again.

Volunteer corn can significantly reduce soybean or corn yield, although research shows volunteer corn is more competitive in soybean than in corn. Clumps of volunteer corn, which emerge from dropped ears, cause more issues than individual plants. Many fields had full ear droppage in 2018, making clumps likely. Theoretically, volunteer corn in corn could help offset yield losses by contributing to yield; however, volunteer corn typically lags behind hybrid corn in development and produces smaller ears with poor seed set. Additionally, large amounts of volunteer corn can potentially cause yield drag in the current year’s corn.

Controlling volunteer corn with herbicides in soybean is feasible, because a number of grass herbicides, such as Select Max, Poast, Assure® II, Fusilade, and Fusion are labeled for this usage. LibertyLink soybean is also available in the marketplace; Liberty can control volunteer corn, but only if the hybrid corn planted last year was NOT Liberty-resistant. Yield impacts are not the only concern with volunteer corn in soybean, however. Volunteer corn can act as a bridge between corn crops for corn rootworm. This can encourage the development of resistance to Bt-corn rootworm hybrids because exposure to sub-lethal doses of the Bt toxin has the potential to accelerate development of resistance to Bt-corn rootworm traits. It’s recommended to control volunteer corn as best as possible to battle the potential corn rootworm problem.
Controlling volunteer corn in continuous corn is more difficult. If only a Roundup Ready corn hybrid was planted the previous year and Roundup Ready + LibertyLink hybrid corn is planted this year, Liberty can be applied for control of the glyphosate-resistant volunteer corn. Remember that Liberty will not be effective if Roundup Ready + LibertyLink hybrid corn was planted last year. Another option is using Enlist™ corn with an “FOP” herbicide like Assure® II. Enlist™ corn is a new multiple herbicide-resistant corn which is resistant to 2,4-D choline, glyphosate, and aryloxyphenoxypropionates (FOPs). If Enlist™ corn is grown in 2019 in a field that was under conventional or Roundup Ready/LibertyLink corn in 2018, volunteer corn can be controlled by applying Assure® II.

Fortunately, there are several options available for managing volunteer corn, it just takes some brainstorming and planning ahead. If you’d like to discuss what would work best for your operation, please feel free to call Claire LaCanne at (507) 332-6165. For an extended version of this article visit:


--Claire LaCanne, UMN Extension Educator, Ag Production Systems