Metproxybicyclone herbicide inaugurates fourth generation of ACCase inhibitors

Syngenta has announced that its new herbicide, metproxybicyclone, has been classified in a new subclass of ACCase inhibitors. The decision was made by the Herbicide Resistance Action Committee (HRAC) and the Weed Science Society of America (WSSA). According to the company, this is the first innovation in this chemical group in almost two decades.

The molecule represents the fourth generation of this class of herbicides. The third, led by pinoxaden, also from Syngenta, entered the market in 2006. The gap between launches highlights the difficulties in developing effective and safe solutions against resistant weeds.

According to Camilla Corsi, the company’s global director of research and development, the new product responds to a growing problem. Herbicide resistance already occurs in 273 weed species, in more than 100 crops and 75 countries. About 40% of these species are grasses.

Metproxybicyclone was developed to address this challenge in soybean and cotton crops in South America, especially in Argentina and Brazil.

The herbicide is expected to be launched in Argentina in 2026, following regulatory approvals. The molecule was designed to control grasses resistant to widely used herbicides, such as glyphosate and clethodim.

In Brazil, the Brazilian Institute of Environment and Renewable Natural Resources (Ibama) issued a Temporary Special Registration for research in May 2024. Main features:

Registrant: Syngenta Crop Protection Ltd., CNPJ: 60.744.463/0001-90

Product trademark: A23434

Product registration number: 40732/23

Chemical name of active ingredient: [3-(2-methoxy4-prop-1-ynyl-phenyl)-4-oxo-2-bicyclo[3.2.1]oct-2-enyl] methyl carbonate

Common name of active ingredient: metproxybicyclone

Approved indication for use: The research aims to test the product in controlling the main weeds (invasive plants that develop in undesirable places) in conditions that allow the use of this product in non-agricultural environments, such as fence lines, industrial areas, highway margins, railways, oil pipelines, terminals and high voltage substations and thus obtain agronomic efficacy reports, physical, chemical, environmental, ecotoxicological and toxicological studies aiming at the submission of the product for new registrations

Preliminary toxicological classification: Class I - extremely toxic

Preliminary environmental classification: Class I - highly hazardous to the environment