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Sponsored: Why Multiple Herbicide Modes of Action Are Essential

Wise use of tools is key to limiting development of resistant weeds

Weeds are clever. Especially when it comes to developing resistance.

To fight back, farmers must plan ahead and include multiple herbicide modes of action in their weed management plan. That means checking labels to ensure products are from different herbicide groups and are effective on the weeds in each field.

Plan ahead, limit weed seedbank

It’s been said many times, but the advice is sound: Begin with a clean, weed-free field at planting. Give the crop the best environment possible to get the nutrients it needs for a strong start. Then round out the weed management plan with additional herbicide modes of action to minimize weed pressure throughout the season and prevent survival of resistant weeds.

“Growers who were successful last year had a plan and started out clean,” says Haley Nabors, Enlist™ field specialist. “In most cases, they started with a burndown and kept the field clean throughout the growing season with residuals and postemergence applications.”

From the time resistance was identified 60 years ago, more than 250 weed species have been documented as resistant. Now, more and more weeds are expressing resistance to multiple herbicides. Alternating between two herbicide modes of action in a growing season may not be enough to thwart these weeds from seeding. With a single female pigweed plant producing about 600,000 seeds, it’s easy to see how the unwanted species can overtake fields.

“You always want multiple modes of action in a field every year,” says Steve Snyder, Enlist field specialist. “I suggest three to four modes of action per crop per year.”

This is the best way to control weeds throughout the growing season and reduce the buildup of the weed seedbank.

Farmers also may have opportunities to use more herbicide modes of action in a field by rotating crops, notes Snyder. Make sure you’re using different modes of action. Even though two herbicides have different brand names, they may share a mode of action. Farmers need to pay close attention to the labels and make sure they are using different herbicide groups with different modes of action that control weeds at different sites of action.

Understand herbicide labels

Snyder and Nabors stress that farmers should double-check herbicide labels to make sure they’re bringing multiple modes of action to bear on tough weeds. Using a program approach to weed management will help ensure farmers can use new postemergence products, including Enlist One™ herbicide and Enlist Duo® herbicide, for years to come.

“Enlist field specialists and our sales representatives can help farmers understand label requirements for our products,” Snyder says. “In addition, we offer internet-based instructions so growers in the field can get quick access to help on their tablets or smartphones.”

Farmers can visit the resources page at for information about Enlist One and Enlist Duo herbicides. Both feature Colex-D® technology, which limits drift and offers near-zero volatility, and can be applied to cotton, soybeans and corn with the Enlist trait.

One key consideration when selecting herbicides is tank-mix flexibility, Nabors adds.

“For instance, with Enlist One herbicide, you have the ability to tank-mix glufosinate, adding another mode of action to postemergence applications,” she says. “This gives you two truly effective modes of action on glyphosate-resistant weeds.”

When farmers apply an effective burndown followed by residual herbicide applications and then a postapplication of Enlist One herbicide and glufosinate, they can employ four or more modes of action in a single season.

“It’s been 30 years since a new class of herbicides hit the market,” Snyder says. “It’s important to keep our valuable herbicides effective as along as possible to control tough-to-manage weeds.”

Visit to learn more about the Enlist™ weed control system. Learn what farmers are saying about this technology at Experiencing Enlist. Also watch our YouTube channel and follow us on Twitter at @EnlistOnline.

®™ Trademark of The Dow Chemical Company (“Dow”) or E. I. du Pont de Nemours and Company (“DuPont”) or affiliated companies of Dow or DuPont. Enlist Duo and Enlist One herbicides are not registered for sale or use in all states or counties. Contact your state pesticide regulatory agency to determine if a product is for sale or use in your area. Enlist Duo and Enlist One herbicides are the only 2,4-D products authorized for use in Enlist crops. Always read and follow label directions. ©2018 Dow AgroSciences LLC.

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