Hopefully, by now all cotton fields have been hand-weeded before viable seed were produced. However, there is one more important step that growers can take to further reduce the seedbank of Palmer amaranth. Neglecting this important step can undo prior efforts to holistically reign in the seedbank of Palmer amaranth.
Once corn harvest is complete, it is easy to forget about those fields for a while, as harvest of other crops will soon begin following corn harvest. As corn is generally harvested rather early in the fall (August – September), small plants that were present in the corn can flourish after harvest. And, new weeds can emerge.
Harvested corn fields provide no shading of the soil surface (light is necessary for pigweed germination) and there is plenty of time and heat units before a killing frost to allow for seed production of Palmer amaranth.
Good news is that Palmer amaranth can be controlled well and relatively economically. A well-timed application of paraquat at 0.75 lb ai/A (3 pt/A of Gramoxone, 2 pt /A of generics) applied prior to seedhead development can effectively control these weeds while significantly reducing the seedbank for the following year.
DON’T NEGLECT TO TAKE ACTION IN THESE FIELDS!!