FMC Files Brazil Registration for World’s First Dual Mode of Action Herbicide ‘Rimisoxafen’

29 September 2026, Brazil: FMC Corporation submitted a regulatory dossier to Brazilian authorities on September 28, 2026, seeking registration of rimisoxafen, the herbicide the Herbicide Resistance Action Committee (HRAC) has classified as the industry’s first active ingredient with two distinct modes of action in a single molecule. The Brazil filing is FMC’s second global regulatory submission for the product, following an application filed with the US Environmental Protection Agency in July 2026.

Rimisoxafen was discovered by FMC scientists at the company’s Stine Research Center and works by simultaneously inhibiting two separate biochemical pathways, phytoene desaturase and solanesyl diphosphate synthase, corresponding to HRAC Groups 12 and 32. HRAC formally recognized this dual classification, the first of its kind, in February 2026. FMC and weed scientists cited in coverage of the classification say the two-pathway mechanism presents a higher resistance barrier than single-site herbicides.

In Brazil, the product targets corn and soybean, which together cover roughly 70 million hectares of Brazilian farmland (about 50 million hectares of soybean and more than 20 million hectares of corn), and is aimed specifically at small-seeded broadleaf weeds including Amaranthus hybridus and Amaranthus palmeri (Palmer amaranth), both of which have developed resistance to glyphosate and to acetolactate synthase (ALS) inhibitor herbicides in parts of the Americas. Leonardo Bastos, FMC’s vice president and chief marketing officer, said Brazilian growers are facing complex weed resistance challenges that demand new and differentiated solutions.

Rimisoxafen is the third novel herbicide active ingredient FMC has advanced to regulatory submission, following isoflex and dodhylex. In June 2026, FMC signed a co-exclusive strategic supply and licensing agreement with Corteva giving Corteva access to rimisoxafen for premix corn and soybean formulations across North and South America; Corteva made an initial prepayment of $200 million under that deal. FMC retains full ownership of the molecule and continues to develop it independently for other crops and geographies outside that arrangement. The companies have said first commercial sales are anticipated by the end of the decade, pending the outcome of regulatory reviews now underway in the United States and Brazil, with additional formulated-product submissions expected in other markets as the process advances.

Neither FMC’s press materials nor Brazilian trade coverage of the filing named the specific Brazilian agency handling the dossier; pesticide registration decisions in Brazil are typically coordinated across three federal bodies, the Ministry of Agriculture and Livestock (MAPA), the health regulator ANVISA, and the environmental agency IBAMA, and dossiers of this kind generally require sign-off from all three before a product can reach market.

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