Bayer Ships New Diflufenican Herbicide Convintro to US Farms
10 November 2026, St. Louis, US: Bayer has shipped the first commercial order of its new herbicide Convintro, marking the US market debut of diflufenican, an active ingredient the company describes as new to the United States for weed control in corn and soybeans.
The company said the shipment left its manufacturing facility in Kansas City, Missouri, and arrived on November 6 at New Century FS, an agricultural retailer in Ruthven, Iowa. Bayer framed the delivery as a milestone marking the start of Convintro’s commercial rollout rather than a change in how the product is formulated or applied. Federal registration for the herbicide has been secured with the US Environmental Protection Agency, though Bayer said individual states still need to grant their own approvals before retailers in each state can sell the product, so availability will vary by region ahead of the 2027 planting season. Shipping the first truckload months ahead of spring planting reflects how retailers typically stage pre-emergent herbicides, since distributors need time to move inventory into warehouses and onto retailer lots before fields are ready for application the following season.
Convintro is built on diflufenican, which Bayer classifies as a Group 12 herbicide that controls weeds by inhibiting carotenoid biosynthesis, interfering with the pigment production that seedlings need to survive early growth. The company positions it as a pre-emergent, early season option meant to be layered into broader weed management programs alongside existing herbicide chemistries rather than used alone.
Bayer is marketing Convintro specifically against waterhemp and Palmer amaranth, two pigweed species widespread across corn and soybean growing regions that have developed resistance to multiple existing herbicide classes. The company said populations of these weeds now resist as many as nine different herbicide sites of action, a level of resistance it says has eroded the effectiveness of existing post-emergent programs and pushed growers to look for new chemistry.
Weed scientists have long recommended rotating between multiple herbicide sites of action, since repeated reliance on a single chemistry class gives surviving weeds more opportunities to pass on resistance traits to the next generation. A pre-emergent product built on a mode of action not previously used in US row crops gives growers an additional option to rotate into that kind of program, rather than a stand-alone replacement for existing herbicides.
Resistant weeds drive yield-loss figures
To make the case for introducing a new site of action, Bayer cited its own figures on the cost of leaving these weeds uncontrolled. The company said waterhemp has produced an average yield reduction of 43 percent over a three-year study period when left unmanaged. For Palmer amaranth, Bayer said soybean yield potential can fall by as much as 79 percent once the weed reaches a density of 2.5 plants per foot of row. Those figures, drawn from sources Bayer cited in its own announcement, underpin the company’s argument that growers need a new mode of action rather than continued reliance on existing post-emergent options, as resistant biotypes continue to spread through the Midwest and mid-South.
Kenin Eubank, Bayer’s US Crop Protection Business Lead, described the Iowa shipment as more than a routine delivery. “There’s more than herbicide on this truck, there’s a new chapter in the fight against resistant weeds,” Eubank said.
State approvals still pending in some regions
Because US pesticide registration requires both a federal EPA decision and separate approval from each state, Bayer said Convintro is not yet registered for use everywhere. The company is directing growers to check state approval status in their own region before planning to use the product, and says state registrations will continue to be added as they are granted. Bayer is pointing growers to its CropScience and Convintro websites, along with a toll-free information line, for updates on where the herbicide becomes available as the rollout continues through the states.
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