Controlling Weeds Amid Rising Resistance

When HPPD-resistant weeds reduce your corn yield’s potential, you need an alternative that fights back.

Once heralded as a revolutionary solution for weed control, the industry is confronting an increasing challenge when it comes to HPPD-inhibiting herbicides: the rise of resistant weeds and dwindling efficacy.

Novel Chemistry for a New Foundation

Introducing Surtain^® herbicide, the latest non-HPPD-inhibitor from BASF. Bringing powerful PPO residual chemistry into a pre- through early-post application, Surtain herbicide offers significant flexibility with a wide application window and up to eight weeks of broad-spectrum control.

With a first-of-its-kind premix with solid encapsulation technology, the active ingredient is suspended in a solution and a solid coating forms on the surface. After applied in the field, the encapsulation begins to dry, forming cracks in the coating. This allows the saflufenacil (Group 14) active ingredient to be activated by rain or irrigation water along with the proxasulfone (Group 15). This novel technology allows full availability of the active ingredients, unlike traditional encapsulation. Surtain herbicide controls or suppresses 79 broadleaf and grassy weed species, including waterhemp and Palmer amaranth. And because it is not activated until it makes contact with water, it provides excellent crop safety.

"It's important to start clean and stay clean. That's why Surtain herbicide is an important foundational residual for farmers," said Josh Putman, BASF Technical Marketing Manager.

Solution to HPPD Resistance

Unfortunately, the overuse of HPPD-inhibiting herbicides has led to the advancement of herbicide resistance and the potential loss of HPPD efficacy, if not managed. To preserve current HPPD products, farmers need to think differently and change their early control programs.

"When BASF created Surtain herbicide, we focused on making sure that we were adding another tool to that toolbox to try to preserve existing HPPD products and not rely on them repeatedly, which is what led to resistance in the first place," said Putman.

Surtain herbicide is backed by six years of trials and more than 160 trials in the Midwest to give growers an effective tool against resistant weeds.

"HPPD-resistant products are still widely used throughout much of the Corn Belt," said Putman. "Post applications are becoming less effective on waterhemp and Palmer amaranth. That is leading to increases in the weed seed bank."

Weeds to Watch

While weed species may differ based on region, waterhemp, Palmer amaranth, kochia and giant ragweed are the most resistant in the Midwest. These invasive weeds not only compete for vital resources on early-season corn stands but can also significantly reduce yield potential.

"Waterhemp alone can reduce corn yields by up to 74% if uncontrolled," said Putman.

Early control is key to giving corn a strong start. Even small weeds can have a significant impact on corn production.

"A six-inch weed left uncontrolled can cause up to 7% yield loss with corn production,”¹ said Putman. "By using a planned, pre-emergent herbicide application, you can eliminate the weed competition and give your corn a chance to establish a healthy stand."

Early Season Weed Control Strategies

Farmers are looking for solutions and turning to their local retailers to find them.

"We need to keep educating farmers about the importance of early-season weed control. That preventative action is key," said Putman. "They trust that we can provide solutions and help them shift their focus to early control, giving them a chance for a better yield potential."

Staying clean into canopy by using a pre-emergent herbicide, like Surtain herbicide, and layering residuals, like Zidua^® SC herbicide, in post applications can give corn a chance to establish that healthy stand without fighting with weeds for nutrients in the soil, water and sunlight.

For More Information

To learn more about how you can diversify your weed control program and prevent resistance, talk with your local BASF technical representatives or visit Surtain-Herbicide.com.

_{¹Knezevic, S. (2015) The critical period of weed control in corn. Cropwatch. https://cropwatch.unl.edu/critical-period-weed-control-corn}