4 Steps to Managing Weed Resistance | Corteva Agriscience™
 11/30/2020

4 Steps to Managing Weed Resistance

Idaho agronomist shares his tips

Controlling weeds is critical to profitability; yet ensuring continued product efficacy requires prioritizing resistance management when developing a weed control program.

“Group 2 resistance is growing more common in our area and is especially prevalent with mayweed chamomile, also known as dogfennel,” says Bob Michels, an agronomist with Infinity Agri-Service in Cottonwood, Idaho. “Italian ryegrass and windgrass are also starting to show resistance to Group 2 herbicides, and we are observing some Group 1 resistance with Italian ryegrass.”

Michels says the repeated use of Group 2 herbicides over many years slowly built up resistance.

“It went unnoticed for a while,” he says. “We documented a few plants here and there, and now we are documenting resistance to Group 2 chemistries to the degree that the uncontrolled weeds are thick enough to negatively affect wheat grade and to cause lodging prior to harvest, which decreases harvest efficiency and, potentially, profitability.”

Michels stresses the importance of growers developing a season-long herbicide program that contains multiple modes of action to manage potential resistance development.

With three active ingredients and a unique site of action provided by Arylex™ active, new WideARmatch herbicide can assist weed farmers’ resistance programs. WideARmatch also offers control of high-anxiety weeds, including Group 2-resistant dogfennel and prickly lettuce.

“It’s a good choice for Group 2-resistant dogfennel, and it’s a preferred choice for tank mixes,” Michels says. “A 3-in-1 product makes farmers happier because they don’t have multiple jugs to deal with. Having one premix limits the products being added to the tank.”

4 Steps to Fight Resistance

Michels recommends wheat growers take these four steps to better manage resistance development:

  1. Rotate sites and modes of action when selecting herbicides for weed control in wheat.
  2. Routinely and properly clean combines to prevent spreading weed seed when moving from field to field.
  3. If you suspect that grassy weeds are escaping herbicide applications, have those weeds tested for resistance.
  4. Don’t treat weeds with less-than-recommended labeled rates of herbicides, per product labels. “You might want to save a buck an acre, but you’re getting what you pay for. With less active ingredient per application, you are increasing plant tolerance to that active ingredient,” he says.

 WideARmatch is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Arylex is a registered active ingredient. Always read and follow label directions.