• Volunteer corn may be present in many soybean fields.
• Volunteer corn can reduce yields and management is a good part of your IPM program.
• There are many herbicide options available to manage volunteer corn.
• Graminicide tank-mixtures with dicamba may require additional planning to ensure success.

Volunteer corn can sometimes be a problem in soybean fields in the year following corn. Volunteer corn is more prevalent in years when we have a dry fall right after harvest because the corn does not germinate and subsequently die following a winter frost or freeze. A short early spring period prior to soybean planting also results in more volunteer corn, because it may not germinate prior to burndown herbicide applications or tillage to prepare fields for planting. If both of the above conditions occur, volunteer corn can present a significant problem in soybeans. While soybean planting started much later this year, it will still be important to manage volunteer corn in these fields during the postemergence herbicide application. 

Research studies have shown that volunteer corn can reduce soybean yields from 5 to 15 bushels per acre.  Plus, controlling volunteer corn is just a good part of your IPM program in terms of decreasing the potential risk of pests developing resistance to traits due to lower levels of gene expression (i.e. corn rootworm, European corn borer, corn earworm, etc.).  Not to mention the value you can create by eliminating the ugly fields that landlords see and may take into account when negotiating future contracts. 

Fortunately, good volunteer corn control options exist in glyphosate-resistant and glufosinate-resistant soybeans. Most postemergence grass herbicides (graminicides) like SelectMax®, Fusilade DX and Assure II® are very effective in controlling volunteer corn and are good tank-mix partners for glyphosate.Be sure to use the appropriate adjuvants to ensure complete volunteer corn control. 

In dicamba-tolerant soybeans, there is some known antagonism of these graminicides when tank mixed with dicamba.Because of this, adjuvant usage is even more important.  Also, increasing the rate of the graminicide may be necessary to get complete volunteer corn control.  Lastly, check the manufacturer’s website to confirm that the graminicide that is chosen is an approved tank mix partner.