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Volunteer Corn (Zea Mays)

Crop Impacts: Soybeans, Barley and Canola

Volunteer Corn 1

About Volunteer Corn:

If appropriate crop and herbicide rotation is not used in fields, volunteer plants will arise. Volunteer Corn is left over from past crops. Sometimes they appear because not all the seeds from the previous crop were completely harvested, many of their seeds can fall on the ground during harvest or they can be spread by farm equipment. If the seeds are able to survive the winter months, it has the potential to germinate and grow in the next year’s crop. The problem with Volunteer Corn is that they can compete with the desired crop in that field for that year, and contaminate the harvest.

Family: Grass family (Poacaea)

Volunteer Corn 2 Volunteer Corn 3

Volunteer Corn Scouting:

Corn is an annual plant that has a simple and straight stem that stands at about 7 to 10 ft. in height, with a pair of large leaves growing out of the internode. with about 8 to 21 leaves in total per plant. The green leaves have a midrib that is lighter in colour; they are linear and can grow between 11 and 40 inches in length. They produce tassels or inflorescence at the top and ears of corn growing off the stems. When scouting Volunteer Corn, they will most likely be noticeably smaller in height and leaf length than they are supposed to be.

Common locations

  • - Soybeans
  • - Barley
  • - Canola
  • - Corn

Volunteer Corn Control:

Prevention & Cultural Control

Make sure to give all equipment that has been used in harvest a good clean to make sure no seeds are transferred. To eliminate any chance of planting the wrong seed, segregate seed supply by trait. There are four main steps you can do to make sure you are doing your best to control the spread of unwanted plants. 1) Go over the herbicides chemistry for burn down application before planting. 2) Integrate post-harvest cultivation in to your field maintenance. 3) Use control measures that can be done in non-crop areas. 4) Plant certified seeds to reduce the chance of unwanted plants from growing. That being said it is impossible to say that a bag is 100% pure seed because of the way seed production happens, and the potential movement of pollen. Overall, for managing unexpected volunteer plants in crop fields you should rotate your crops, rotate the group herbicide that is used, rotate herbicide tolerant plants, rotate the time in which the herbicides need to be applied, and finally till your fields.

Chemical Control

Due to hybrid corn varieties that are resistant to herbicide, makes applying herbicides to kill unwanted corn a little more difficult. Knowing the herbicide traits that have been on corn in previous years is critical. Trying to control older and larger plants is much more difficult and time consuming, therefore timely application is critical. Herbicides will be ineffective if applied when the plant is under stress. The herbicides will have more effect right before or right after rain due to the fact that the roots of the plants are taking in water at the time, which in turn means they will be taking in the herbicide as well. For optimal herbicide control, it should be done when the weed is about 2 to 3 inches tall.

Raptor herbicide is a chemical herbicide that provides good control of Volunteer Corn. If Volunteer Corn is not Roundup ready, applying glyphosate can be extremely effective. Applying herbicides in the ACC-ase family have been shown to work well for control of Volunteer Corn in soybeans. Also using post-grass herbicides in infested soybean fields such as Assure II, clethodim, Fusilade and Select, gets rid of Volunteer Corn.

Here are a few options to take control of Volunteer Corn in new corn fields. Ignite herbicide will reduce the competiveness of Volunteer Corn by killing the emerged leaves. If Volunteer Corn has traits resistant to the active ingredient glyphosate, applying either SelectMax or paraquat can be used. Between applying SelectMax and planting, there should be a minimum of 6 days. Also, it is important to know that paraquat is a contact herbicide, meaning it might not be able to provide total control over Volunteer Corn. Finally, herbicides in the ACC-ase family such as Fusilade, Poast or Assure, can work well in eradicating Volunteer Corn in corn fields.

Latin / Alternative Volunteer Corn names:

  • - Zea Mays
  • - Masize

Additional Volunteer Corn Resources

http://www.croplife.ca/issues/herbicide-tolerant-volunteers

http://www.britannica.com/EBchecked/topic/137741/corn

http://www.croplife.ca/wp-content/uploads/2012/02/croplife_eng_apr112.pdf

http://agron-www.agron.iastate.edu/~weeds/Ag317-99/id/WeedID/volcorn.htm

http://www.extension.iastate.edu/CropNews/2009/0519hartzler01.htm

http://extension.psu.edu/plants/crops/news/2013/05/control-of-roundup-ready-corn-volunteers-or-replanting

http://extension.psu.edu/plants/crops/news/2013/05/control-of-roundup-ready-corn-volunteers-or-replanting