The safety of SDHI fungicides has been concerned again after the approval of Isopyrazam in Brazil and the EU

Brazil's National Health Surveillance Agency (ANVISA) announced on November 17 that it has opened a public consultation on fungicide products containing the active ingredient Isopyrazam. The 60-day public consultation is intended to collect public comments and suggestions on the regulations related to the biocide.

Isopyrazam belongs to the SDHI class of fungicides. Its mechanism of action is to inhibit the action of succinic dehydrogenase reductase in the electron transport chain on the inner mitochondrial membrane, so that pathogenic fungi can not produce energy through respiration, and then disrupt the growth of bacteria. The key step is to block the Succinate dehydrogenase, which is necessary for the fungus to breathe.

Brazil is one of the world's major agricultural producers, and the safety of fungicides is a concern. Isopyrazam is an active ingredient in several Syngenta products, and if the public feedback is negative, it will directly affect the sales prospects of the relevant pesticide products in Brazil.

At present, some international scholars have studied SDHI and pointed out its toxicity. The results of a study by French researchers show that SDHI family fungicides are not only toxic to fungi, but also to earthworms, bees and human cells. The study, led by the French National Institute of Health and Medical Research (Inserm) and published in the scientific journal Plos One, specifically highlights the toxicity of eight SDHI family fungicides (Flutolanil, Fluopicolide, Boscalid, Fluxapyroxad, Fluridazole, Penthiopyrad, Bixafen and Isopyrazam).

In fact, as early as May 2022, the EU has officially revoked the approval registration of Isopyrazam, due to its classification as a reproductive toxicity Class 1B, which came into effect on June 8, 2022.

To date, the International Action Committee on Fungicide Resistance (FRAC) has listed 24 SDHI fungicides, These include five products of Syngenta (Isopyrazam, Sedaxane, Benzovindiflupyr, Pydiflumetofen, Cyclobutrifluram), five products of Bayer (Fenuram, Bixafen, Fluopicolide, Fluridazole, Isoflucypram), and three products of BASF (Benodanil, Boscalid, Fluopicolide).), 2 products of the United States of America (Carboxin, Oxycarboxin), 2 products of Sumitomo Chemical (Furametpyr, Inpyrfluxam), 2 products of Nihon Nohyaku(Flutolanil, Pyraziflumid), 1 product of Kumiai Chemica(Mepronil), 1 product of Nissan Chemical (Thifluzamide), and 1 product of Mitsui Chemical (Penthiopyrad), 1 product of Ishihara Sangyo Kaisha(Isofetamid), 1 product of Isagro (Fluindapyr, now acquired by FMC).

Today, Isopyrazam is facing a strict approval environment in the Brazilian and European markets, and whether it will spread to other products under the SDHI category, relevant companies need to pay close attention to its regulatory policy changes.