Several corn fields had ryegrass escape glyphosate + dicamba early burndown. These fields were then retreated with paraquat + atrazine or glyphosate + atrazine at planting that also did not provide good control (picture right). The time to control ryegrass is prior to planting. The most consistent way to control it is sequential paraquat applications spaced about 10 days apart.
There have been several questions about what to do with this existing ryegrass in emerged corn. Unfortunately, the only answer that has the potential to provide good control is a chopping crew. My colleague with Mississippi State University, Dr. Jason Bond has done as much work as anyone on this weed and he tells me that herbicides like Accent or Steadfast will at best provide about 40 to 60% control and possibly cut down on seed production. Other herbicides like Capreno or Halex GT will perform no better. According to his data, Liberty would probably provide the most robust suppression of any herbicide options available (65%). Just based on my experience utilizing Liberty plus atrazine tankmixes, I would expect that tankmix to provide better control than Liberty alone. Of course, this Liberty option assumes that the corn is Liberty Link. Jason’s last statement to me was to advise growers with this problem to make sure the other weeds in these corn fields are controlled so they do not pile on to the competition that is occurring from the ryegrass.