By Brian Hefty

You need 3 pre-emerge modes of action if you want to stop resistant weeds, prevent future weed outbreaks, and maximize soybean yields! While 3 modes of action may sound expensive, it should only cost $12 to $28 per acre.

What Are the 3 Pre’s We Suggest?

  1. PPO – either Authority or Valor (2 to 3 oz/acre). Net cost after rebate = $6 to $9.
  2. Yellow – either Trifluralin (conventional-till, 1.5 pints/acre, $4) or Prowl H2O (no-till, 2.6 to 3 pints/acre, $13 to $15)
  3. Metribuzin (0.17 to 0.33 pounds/acre, $2 to $4). Go low rate when soil pH > 7.4.

Why 3 Instead of 2 Modes of Action?

3 modes gives you added control. In many cases, we talk about going from 95% control to 99% or higher. That’s a big difference. Plus, adding an extra mode of action extends residual, lessens the chance for future weed resistance, and increases yield in most cases.

Can I Apply All 3 Modes of Action at the Same Time?


Since I Have Liberty or Xtend, Can’t I Just Spray Those Products Twice Post-Emerge to Clean Up All My Weeds?

Yes, that might work, but look at the cost. Adding another trip will run far more than adding a 3rd mode of action pre-emerge. Plus, spraying dicamba a second time post-emerge may not be possible due to label restrictions on timing.

There Are Many Other Pre-Emerge Herbicides. Why Do You Recommend the Ones Listed Above?

Authority, Valor, the yellows, and metribuzin cannot be used post. Many of the other pre-emerge herbicides can be saved for post, just in case you need them. The main reason we like the combination we listed is the weed control is superior to anything else. Almost no weeds are resistant to the products we listed, and the premix that gives you 3 modes of action has been tried, tested, and proven across the United States on millions of acres by thousands of farmers. It works. If nothing else, at least take your weediest fields this year and try this combination. If you are fighting waterhemp, Palmer pigweed, kochia, ragweed, lambsquarters, marestail, or a variety of other annual weeds, you will be really happy with the residual control. If you need added burndown (the PPOs plus metribuzin provide good, not great burndown), mix in Roundup, dicamba (Xtend only), Liberty, or Gramoxone.