Key Takeaways
New weed management tools: Three new herbicide active ingredients are moving closer to commercialization, offering additional options for managing herbicide-resistant weeds in corn and soybean production.
Resistance management: New herbicide groups give growers more options to rotate and layer herbicides, helping slow the development of herbicide resistance in weeds such as waterhemp and Palmer amaranth.
Not available yet: These products are still progressing through the registration process. Watch for final EPA and Nebraska registrations, product labels and availability before planning their use.
Several new herbicide active ingredients are moving one step closer to growers' fields, offering additional tools for managing herbicide-resistant weeds in corn and soybean production.
In its June 2026 registration actions, the U.S. Environmental Protection Agency (EPA) completed registration decisions for several new herbicide active ingredients, and three are particularly relevant for corn and soybean production: diflufenican, epyrifenacil and trifludimoxazin. None are on the shelf yet, but all three are progressing toward the market, and each adds a useful option for managing herbicide-resistant weeds — especially waterhemp and Palmer amaranth.
On the regulatory side, two of the three herbicides — diflufenican (Convintro) and epyrifenacil (Rapidicil) — received EPA registration on June 30, 2026, and trifludimoxazin (Tirexor) advanced through review over the same period.
Together, these herbicides introduce two modes of action — Weed Science Society of America (WSSA) Group 12 and 14 — that could expand options for managing herbicide-resistant weeds.
| Active ingredient / Product | WSSA Group (site of action) | Primary Use and Crops | Why It Matters |
|---|---|---|---|
Diflufenican Convintro | Group 12 — phytoene desaturase (PDS) inhibitor | Preplant / preemergence residual herbicide for pigweeds in corn and soybean | First effective Group 12 (PDS) site of action for pigweed control in corn and soybean |
Epyrifenacil Rapidicil | Group 14 — protoporphyrinogen oxidase (PPO) inhibitor | Preplant burndown and cover crop termination in field corn, soybean, wheat, canola, fallow, and non-crop areas | Fast, broad-spectrum burndown herbicide |
Trifludimoxazin Tirexor; Voraxor with saflufenacil | Group 14 — PPO inhibitor | Residual (PRE) plus foliar herbicide in corn, soybean, cereals, and others | Provides both residual (PRE) and burndown activity |
Diflufenican (Convintro)
A New Site of Action Herbicide
Diflufenican is a WSSA Group 12 herbicide that controls susceptible weeds by disrupting carotenoid production, causing the characteristic bleaching symptoms associated with this herbicide group. It is a soil-applied residual herbicide for preplant and preemergence control of waterhemp, Palmer amaranth and other pigweed species in corn and soybean.
Why this matters: According to EPA, diflufenican is the first effective PDS-inhibiting herbicide for control of pigweeds in corn and soybean — a new site of action for the two crops. Group 12 chemistry has seen little use in Nebraska row-crop systems, so it offers a distinct rotation and tank-mix partner rather than another version of chemistries growers already rely on. Because many Nebraska waterhemp and Palmer amaranth populations are already resistant to multiple herbicide groups (commonly Groups 2, 4, 5, 9 and 27, with Group 14 resistance also documented), this new residual site of action for pigweeds is a valuable addition to preemergence weed management programs.
Epyrifenacil (Rapidicil)
Fast Burndown and Cover Crop Termination
Epyrifenacil is a WSSA Group 14 PPO inhibitor. It is a fast-acting, contact herbicide intended for preplant burndown and cover crop termination, with a broad label spanning field corn, soybean, wheat, canola, fallow ground and non-crop areas. It can provide broad-spectrum control of both broadleaf and grass weeds, including weed populations resistant to older PPO-inhibiting herbicides.
For Nebraska, this is especially relevant as more growers adopt no-till and cover crops, making reliable, fast burndown and cover crop termination increasingly important. The first commercial product containing epyrifenacil (marketed under the Empera brand) is expected in late 2026 or early 2027.
Trifludimoxazin (Tirexor/Voraxor)
A PPO-Inhibiting Herbicide for Burndown and Residual Weed Control
Trifludimoxazin is a WSSA Group 14 PPO inhibitor. Depending on application rate, trifludimoxazin provides residual preemergence control of germinating broadleaf and grass weeds, as well as foliar burndown of emerged weeds. It’s labeled for corn, soybean, cereals and other crops — often as a tank-mix partner (for example, with saflufenacil, marketed as Voraxor).
Trifludimoxazin will come to the market in two forms. Tirexor contains only trifludimoxazin — a liquid soluble-concentrate formulation (4.17 pounds active ingredient per gallon). Voraxor pairs trifludimoxazin with saflufenacil (the active ingredient in Sharpen) and is aimed at preplant burndown ahead of corn, soybean and small grains.
What Growers Should Know
- None are available yet. All three herbicides are moving toward market, so none will be on the shelf for use this season. Watch for finalization of EPA registration, Nebraska Department of Agriculture registration, and for the product label before planning any use.
- Expect more complex labels. These new registrations are likely to carry runoff, erosion, endangered species and spray drift requirements. Read the label carefully once products are available.
- The label is the law. Follow the most current EPA- and state-approved label directions.
Sources and Further Reading
- Weed Science Society of America. WSSA Applauds EPA's Advancement of Six New Herbicides (July 3, 2026). https://wssa.net/2026/07/wssa-applauds-epas-advancement-of-six-new-herbicides/
- Federal Register. Diflufenican; Pesticide Tolerances (June 30, 2026; FR Doc. 2026-13180). https://www.federalregister.gov/documents/2026/06/30/2026-13180/diflufenican-pesticide-tolerances
- Federal Register. Epyrifenacil; Pesticide Tolerances (June 30, 2026; FR Doc. 2026-13193). https://www.federalregister.gov/documents/2026/06/30/2026-13193/epyrifenacil-pesticide-tolerances
- EPA docket (diflufenican registration): https://www.regulations.gov/document/EPA-HQ-OPP-2021-0435-0046
- EPA docket (epyrifenacil registration): https://www.regulations.gov/document/EPA-HQ-OPP-2022-0354-0081
- EPA docket (trifludimoxazin response to comments): https://www.regulations.gov/document/EPA-HQ-OPP-2022-0649-0043
- DTN / Progressive Farmer. EPA Approves Herbicides to Combat Waterhemp, Palmer Amaranth in Commodity Crops (July 1, 2026). https://www.dtnpf.com/agriculture/web/ag/crops/article/2026/07/01/epa-approves-herbicides-combat-crops
- AgWeb. New Herbicide Chemistries Move Closer to Farmers' Fields After EPA Action (July 2026). https://www.agweb.com/news/crops/crop-production/new-herbicide-chemistries-move-closer-farmers-fields-after-epa-action
