Marestail and Waterhemp Control Options in Xtend and XtendFlex Soybeans
With the June 30 cut off date to spray dicamba passed, here are some remaining options from Mike Hunter, Field Crop Specialist, CCE North Country Team.
For soybean growers that have resistant tall waterhemp and palmer amaranth in soybeans there are other effective herbicide options available. The postemergence control of resistant tall waterhemp and palmer amaranth in all soybeans, including conventional, can be achieved by applying Reflex or Flexstar (fomesafen) or Prefix (s-metolachlor + fomesafen) or Warrant Ultra (acetochlor + fomesafen) before the weeds reach 3 inches tall. If necessary, a late rescue treatment of Cobra (lactofen) can be applied.
Unfortunately, for soybean growers that have multiple resistant marestail (Groups 2 and 9) in Xtend soybeans there no other effective postemergence herbicides to control this problematic weed without using one of dicamba herbicides. Postemergence applications of Reflex, Flexstar and Cobra, will not control marestail.
For growers that planted XtendFlex soybean, Liberty (glufosinate) herbicide will provide an additional option for the postemergence control of marestail under 6 inches tall. Once marestail is over 6 inches tall it becomes increasingly difficult to control. For best results, apply 32 to 43 ounces of Liberty plus 3 pounds spray grade ammonium sulfate per acre using 20 gallons water as a spray carrier to ensure adequate coverage. Hot, sunny, humid days provide ideal conditions for the application of Liberty herbicide. Consider making applications between dawn and two hours before sunset for improved control of some tougher to control weeds such as marestail. Liberty herbicide can be applied up to R1 or beginning bloom stage in soybeans.
Don’t Miss Out on the 2022 NY Corn and Soybean Yield Contests
The annual corn and soybean yield contests sponsored by the New York Corn & Soybean Growers Association are underway. The yield contest entry form and contest rules can be found here: 2022 NYCSGA Yield Contest Entry Form . Entry forms must be postmarked by August 30. Entries can be mailed to Brandie Waite at CCE Genesee, 420 East Main St, Batavia, NY 14020 or emailed to Mike Stanyard at mjs88@cornell.edu. Cost is $30 per entry. This year the overall corn and soybean champions win an all-expense paid trip for two to the 2023 Commodity Classic in Orlando, FL.
