Herbicide Modes of Action

Bryan Young of Southern Illinois University at Carbondale had one of the most useful presentations of the program last Thursday at the CCA Convention.  He talked about how to manage herbicide resistance by knowing herbicide modes of action and active ingredients.  He present a chart that divides herbicides into groups that represent the modes of action and active ingredients.  Knowing how to attack your herbicide resistance in the past has involved a lot of research sometimes because of similarities in naming products and because of the almost endless number of brand names and combinations.  Here is the chart that Dr. Young presented.  Agweb has this chart which is similar.  You need to pick from at least 2 products from two different groups that are effective against the weeds you want to kill.  For example, do not use a group 9 product if you have glyphosate resistant weeds.  Here is a good explanation of what the mode of action terms mean.  This article from Iowa State University talks about where to find herbicide group and how to use it. The screen shot below shows where to find group numbers on the label.