I have received this question a few times this week. Dr. Culpepper, UGA Cotton Weed Specialist, preaches that preemergence herbicides are the most effective tool to prevent resistance to post herbicides. Research conducted across GA during 2018/2019 showed that an effective preemergence herbicide mix reduced the number of pigweed needing to be controlled by the first POST or topical sprayby 99.8%. Figure 6 below illustrates the number of emerged Palmer per acre when Reflex, Direx, or Warrant is used along PRE. Please notice the decrease in Palmer emergence when tankmixes are used.
The figure below shows that tankmix combinations for preemerge cotton herbicides for the management of Palmer amaranth.
