Mark VanGessel, Extension Weed Specialist; firstname.lastname@example.org
This spring has been very challenging for marestail control. A number of fields were sprayed early, when horseweed plants well under 6 inches tall, and got excellent control of emerged plants. But this spring we have seen fields with lots of plants that emerged after the initial burndown treatment. In many cases horseweed plants that emerged in April were controlled with a second burndown application that included Liberty or Gramoxone. More frustrating are those plants that were not killed with the initial burndown treatment. Most of these plants were treated when they were over 6 inches tall, or not treated with a full rate of the burndown mixtures. At this time, options are very limited for these fields and often decisions need to be made on a field by field basis.