Two new Group 14 herbicides — epyrifenacil and trifludimoxazin — are killing Palmer amaranth populations that survive 24 ounces of Cobra, according to University of Tennessee weed specialist Larry Steckel. Over the next several years, farmers will gain these actives, a first-in-class Group 12 residual for soybeans, and new trait packages tolerant to mesotrione. Whether any of it holds up depends on stewardship from the first pass.

"I think we all have that mentality of, 'Well, I just want another Roundup,'" said Steve Gauck, regional agronomy manager for Beck's. "And that's just not coming."

New PPOs deliver on resistant pigweed

University research suggests epyrifenacil and trifludimoxazin control at least some weed populations resistant to older PPO herbicides. Steckel has run both against PPO-resistant Palmer amaranth in his program. "They're killing our pigweed that you can't kill with 24 ounces of Cobra," he said.

At an Iowa event this summer, WinField United demonstrated Valent's Rapidicil herbicide technology, which contains epyrifenacil. Regional agronomist Tyler Steinkamp compared Rapidicil with BASF's Sharpen in a burndown demonstration. Sharpen's control was "still not bad," he said. The Rapidicil plot was "absolute devastation."

The new chemistry also brings grass activity that older foliar PPOs such as Ultra Blazer, Flexstar and Cobra lack. "These will pick up the resistant ones, so that'll be a game changer there," Steckel said. "And they've got a lot of grass activity."

University of Illinois Extension weed scientist Aaron Hager has seen a similar response in waterhemp. In his tests against a known PPO-resistant population, trifludimoxazin outperformed commercially available PPO herbicides — though it did not deliver complete control.

Why would a new Group 14 product control weeds already resistant to Group 14? Resistance to one PPO inhibitor doesn't mean every molecule in the group behaves the same. "If there's a subtle change in how it binds, or where on the enzyme that it actually binds to, then that can make a difference," Hager explained.

Diflufenican: new mode of action, narrow spectrum

Diflufenican is the first Group 12 herbicide registered for U.S. corn and soybeans, giving pigweed control a residual site of action soybean growers have never used. "In soybeans, they've never seen this mode of action," Steckel said. "So it's definitely going to be an additional tool there."

But different does not mean standalone. Steckel called diflufenican a "one-weed wonder" because of its narrow spectrum — it needs pairing with other effective residuals for grasses and larger-seeded broadleaves. Hager agreed. "Does it have activity on Amaranthus? Yes, it does," he said. "Is it head and shoulders better than other products that are in the marketplace for soil applications? Probably not, in my opinion."

Crop response may also raise eyebrows. "You'll see some white speckling on the leaves," Hager said. The symptoms are temporary, but noticeable when scouting soybeans shortly after emergence.

Trait pipeline: 2027 through 2029

Bayer's Vyconic soybeans, expected to begin commercial introduction for the 2027 planting season, stack tolerance to five herbicides: glyphosate, glufosinate, dicamba, 2,4-D and mesotrione. Bayer cautions that trait tolerance does not cover every formulation of those actives — farmers must follow labels and apply only approved in-crop products.

BASF plans to launch its NemaSphere nematode resistance trait on an Enlist E3 platform in 2028, pending regulatory approval. Syngenta and M.S. Technologies are developing Enlist E3 Expance, which adds tolerance to several HPPD herbicides, with commercial availability expected in 2029, pending approvals.

"There's going to be areas where this is going to be very valuable," Gauck said — specifically where a field's weed and resistance profile matches what the trait offers. Where existing herbicides still work, growers may be better served reserving mesotrione. Running it through soybeans as well as corn increases selection pressure on a chemistry that remains critical in corn.

There is value beyond postemergence control, though. Mesotrione tolerance could reduce early-season injury from carryover following corn herbicide programs, protecting yield potential, said Mitch Larson, a WinField United market development agronomist in eastern and central Iowa.

Resistance may arrive before the trait does

Here is the catch. Weeds have already met these sites of action in other crops. Steckel said testing across the North Delta has found widespread Group 27 HPPD resistance in Palmer amaranth, including mesotrione. In many fields he has evaluated, he expects little additional postemergence control. "We're going to have resistance before the trait ever rolls out," he said.

Midwest waterhemp tells the same story. University of Illinois researchers first documented HPPD-resistant waterhemp in 2009, and Hager said resistance is now common in Illinois — probably more widespread than farmers realize. "I think that chemistry has been greatly compromised from all the years that we've used it in corn," he said. "I don't know how you really build a robust program around that chemistry, if it's going to now be used in soybeans."

The critical distinction for buyers: a new active ingredient is not necessarily a new site of action, and trait tolerance says nothing about whether the weeds in a given field are still susceptible.

Break the cycle

Gauck sees the new tools' greatest value in strengthening residual programs that stop weeds emerging, not in postemergence rescue. He pointed to soybean production before glyphosate-tolerant varieties — heavier reliance on preemergence herbicides, narrower rows, and other preventive practices. "I think we have to start thinking that way again," he said. His recipe: start clean, lay down a strong residual, and layer another residual after emergence when appropriate.

"The better job we can do up front in keeping our weed pressure down, the less pressure we're going to put on our post passes of chemistry," WinField's Steinkamp said.

The urgency is rising. In 2026, Steckel began seeing glufosinate fail more frequently in his area, weakening another postemergence pillar. "The big thing is, just trying to keep it from ever coming up and overlaying residuals," he said.

Hager said history is unambiguous about what happens when farmers lean on the next chemistry to fix the resistance the last one created. Over recent decades, waterhemp has evolved resistance to ALS inhibitors, PPO inhibitors, glyphosate, HPPD inhibitors and more. "You cannot solve a problem that's caused by using herbicides simply by using them differently or using different herbicides," he said.

His long-term target is zero seed return. "If you want to be sustainable, if you want to preserve the effectiveness of these new chemistries, then you have to preclude or eliminate seed production," Hager said.

Farmers watching the pipeline should track Vyconic's 2027 rollout, diflufenican label details, and rapidicil commercialization — and plan residual programs that prevent escapes from setting seed from the very first season these tools reach the market. "The stewardship cannot start five years after they enter the market," Hager said. "The stewardship has to begin the first time that they're used. If not, we're going to repeat the same mistakes that we've made for more than 30 years now, with this species."