Dicamba can have a good fit in spring preplant burndown programs, especially for control of overwintered marestail in fields not treated the previous fall. We typically recommend a preplant burndown that includes at least two herbicides with substantial activity on marestail in this situation, such as Sharpen + 2,4-D or Gramoxone + 2,4-D + metribuzin. Dicamba is the most effective burndown herbicide on glyphosate-resistant marestail in the spring though, and in our research has usually killed or at least stopped emerged marestail in their tracks without help from other herbicides.

Palmer amaranth has shown up in a few more places in Ohio this summer at a range of infestation levels, and waterhemp has also become more prevalent. Newly discovered Palmer infestations in some fields were too high to be remediated by walking fields and removing plants, although there is still some potential to mow down weeds and soybeans to prevent seed production and even bigger problems next year. Infestation level in a few other fields was low enough to allow removal of Palmer amaranth plants by a crew of concerned people.