Cotton Palmer Amaranth And Goosegrass Rescue Treatments

DR. LARRY STECKEL

JACKSON, TENNESSEE

All the frequent rain lately has made it difficult to spray fields timely. This has left some cotton fields with large goosegrass and Palmer amaranth.  The typical post application to control both those weeds is a tankmix of Liberty and clethodim.  This tankmix will typically provide fair control of large goosegrass.  However, we have found some goosegrass populations where that tankmix is not very effective.  Palmer amaranth too often will recover. In those cases, hooded or post-direct applications should be considered.

Hooded or Post-Direct Application for Palmer Amaranth

Liberty 32 ozs + Direx 32 oz/A or Caparol 32 oz/A or Valor 1.5 ozs/A or Zidua 3.2 ozs or Dual Magnum 16 ozs  Cotton must be at least 6” tall.

Advantages: It will control horseweed up to 10” in height.  Good control of many broadleaf weeds including Palmer amaranth and morningglory species. Liberty has a lot of surfactant already present so additional surfactant is not needed. Most cotton now has good Liberty tolerance and sloppy post direct is not as damaging when tankmixed with Zidua or Dual Magnum.

Considerations:  In order to protect from resistance developing, consider using a paraquat product if Liberty (glufosinate) has already been applied over the top.

Hooded only Applications

Paraquat (Gramoxone Inteon 32 oz/A) + Direx 16 oz/A or Caparol 32 oz/A or Valor 1.5 ozs/A- Cotton must be at least 12” tall.

Advantages: This is the most consistent mixture to control large Palmer (>12”)

Considerations: Needs to be applied carefully!  Use 0.25% COC for best results on large Palmer (>6”). As always with paraquat, be mindful of mix order and water pH.   ∆

DR. LARRY STECKEL

UNIVERSITY OF TENNESSEE