Had Your Auxin Training Yet?

By: Harold Watters, Ohio State University Extension agronomist

I just sat through my second training of the season. Labels changed for all of the soybean dicamba products last fall; and the label says you will attend dicamba training every year. That means everyone who uses a dicamba product on soybeans must attend auxin training from the manufacturer; contact your seed dealer or herbicide supplier to see when yours is happening. If you missed it for the product you are using, that’s OK, you can attend any of the manufacturers’ training sessions to get the update.

From my one and a half hour training I learned that to use the products you must:

  • Keep records.
  • Follow buffer requirements. And they have changed since last year.
  • Use no AMS.
  • Apply with an approved nozzle, with a minimum spray volume of 15 gallons per acre.
  • At 24 inches above the canopy.
  • In winds between 3 and 10 miles per hour.
  • But drive below 15 miles per hour.
  • Spray small weeds within 45 days of planting.
  • Anyone who handles or sprays dicamba must be a licensed applicator, and have been through the auxin training.
  • Rinse three times before and after application. Record that effort.
  • Get a fit test done for your respirator. Annually.
  • And more…

The current labels for the dicamba-soybean products say we shall spray 4-inch or smaller weeds, but one farmer pointed out to me that the sales representative showed data in their auxin training class that their product will take down 12-inch weeds. Ohio farmers already know how to stretch a ruler, so let’s teach that to spray small weeds is the best way to delay the development of resistant weeds. And oh yes, scout before and after your application. Do remember we already have weeds in Ohio resistant to glyphosate and to auxin herbicides.

So how do we reduce the potential of resistance development?

  1. Use a pre-emergent herbicide,
  2. Spray post to small weeds
  3. Allow no seed production. Go rogue to remove those seed heads.


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