How to Properly Use Dicamba on Soybeans

April 03, 2018
 

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As the growing season approaches it is important for farmers to understand how to use dicamba on resistant soybean varieties. Todd Gleason has more with University of Illinois weed scientist Aaron Hager.

The following is an excerpt from the March 23 farmdocdaily article posted by University of Illinois Weed Scientist Aaron Hager.

Steps for Successful Weed Management in Dicamba-Resistant Soybean

Step 1

  • plant dicamba soybean seed into a weed-free seedbed
  • achieve a weed-free seedbed through the use of preplant tillage, an effective burndown herbicide(s), or a combination of tillage and burndown herbicides

Step 2:

  • select and apply within 7 days of planting a soil-residual herbicide that targets your most problematic weed species; if desired (and labeled), add dicamba and an appropriate buffer
  • for waterhemp or Palmer amaranth, select a product containing the active ingredients from one of the following categories of control:
Excellent Good Acceptable
sulfentrazone pyroxasulfone     S-metolachlor/metolachlor
flumioxazin metribuzin acetochlor
fomesafen+metolachlor     dimethenamid pendimethalin
  • Excellent: greatest efficacy on Amaranthus species and longest residual control
  • Good: good efficacy on Amaranthus species, residual control generally not as long
  • Acceptable: stronger on grass species but with some activity on Amaranthus species

Step 3:

  • scout fields 14 days after planting, apply dicamba at 0.5 lb ae/acre when weeds are less than 3 inches tall and when conditions allow for the application, consider adding an approved soil-residual herbicide to the tank mix

Step 4:

  • scout treated fields 7 days after the dicamba application; if control is not complete or another flush of weeds has emerged, consider using non-dicamba options for complete control; examples include alternative herbicides, cultivation, and hand roguing goal should be zero weed seed production