Managing Palmer Amaranth

DR. LARRY STECKEL

JACKSON, TENNESSEE

   Judging by our research plots as well as walking some cotton and soybean fields most Pre applied herbicides are playing out about 7 to 10 days quicker than last spring (Picture 1). The frequent rain would most likely be the reason for this.

   What is performing similar to last year is dicamba control of Palmer amaranth. In fields where dicamba failed to control Palmer amaranth in 2021 we are seeing similar results this spring (Picture 2). Hardly a shocking development, but in these fields follow up Liberty applications with a residual herbicide for Palmer amaranth need to be applied ASAP. Our research clearly shows that a follow-up Liberty application with in 7 days of the Palmer amaranth escaping dicamba controls those escapes much better than waiting several weeks and applying Liberty.

   In cotton, if Liberty is not available, consider getting the hoods out and applying diuron + MSMA or paraquat + diuron. In soybean another application of dicamba followed by Cobra, Flexstar or Ultra Blazer may help thin down the pigweed escapes. ∆

   DR. LARRY STECKEL: Extension Weed Specialist, University of Tennessee

 (Picture 1) Pre applied herbicide breaking earlier than in 2021

 (Picture 2) Palmer amaranth escaping Warrant PRE followed by glyphosate + Engenia + Outlook