Bixlozone (Bixlozone)

Bixlozone (bixlozone) is a selective herbicide developed for the control of annual weeds, including resistant grasses and broadleaf plants, in various agricultural crops such as cereals, canola, corn, legumes, rice and sugarcane.

Common name (ISO): Bixlozone

Synonyms: F9600 (development code); Isoflex (trademark for the active ingredient); Azugro e Ezanya (product trademarks)

Gross chemical formula: C12H13Cl2NO2

Number CAS: 81777-95-9

Chemical class: isoxazolidinone herbicides (belongs to the isoxazolidine family, with a chemical structure that includes an isoxazolidinone ring substituted by chlorinated and methyl groups).

Development history: Bixlozone was discovered and developed by FMC Corporation. It was first described in 1981 in a joint patent with clomazone (another similar herbicide). However, at the time, FMC chose to commercialize only clomazone, postponing the development of bixlozone due to technical and market challenges. The compound remained in research for decades, with studies on its metabolism and selectivity in plants. In 2018, FMC announced bixlozone as a new herbicide in the isoxazolidine family, highlighting its effectiveness against resistant weeds. Development focused on formulations that improve stability and in-plant activation, culminating in regulatory filings in 2020. Global commercialization expanded rapidly, with an emphasis on regions with herbicide resistance problems, such as Australia and Europe. FMC uses the trademark Isoflex for the active ingredient.

Mode of action: Bixlozone is a proherbicide that requires metabolic activation in plants to produce its phytotoxic form (5-ketobixlozone). It acts as an inhibitor of carotenoid biosynthesis (HRAC/WSSA Group 13), specifically by blocking the enzyme 1-deoxy-D-xylulose 5-phosphate synthase (DXS) in the non-plastoquinone mevalonate pathway, essential for photosynthesis. This causes bleaching of susceptible plants, with absorption primarily through roots and young shoots, exhibiting both systemic and contact activity. It is effective against weeds in early stages of development, with low volatility and moderate persistence in the soil.

Patent numbers: US 4.405.357 (original, 1981, covering bixlozone and clomazone); WO 2008/075065 A2 (herbicidal compositions for wheat); WO 2024/073020 A1 (mixtures with pethoxamide); WO 2024/073023 A1 (encapsulated compositions); WO 2025/006659 (mixtures with photosystem I electron diverters); EP 4593610 A1 (water-dispersible granules); and WO 2024/073021 A1 (dispersible granule formulations).