Pydiflumetofen belongs to the large family of SDHI pesticides, it is used as broad spectrum fungicide in agriculture to protect crops from fungal diseases. It was first marketed by Syngenta in 2016 using their brand name Miravis. The compound is an amide which combines a pyrazole acid with a substituted phenethylamine to give an inhibitor of succinate dehydrogenase,[3] an enzyme that inhibits cellular respiration in almost all living organisms.[4]
History
Inhibition of succinate dehydrogenase, the complex II in the mitochondrial respiration chain, has been known as a fungicidal mechanism of action since the first examples were marketed in the 1960s. The first compound in this class was carboxin, which had a narrow spectrum of useful biological activity, mainly on basidiomycetes and was used as a seed treatment.[5][6] By 2016, at least 17 further examples of this mechanism of action were developed by crop protection companies, with the market leader being boscalid, owing to its broader spectrum of fungal species controlled. However, it lacked full control of important cereal diseases, especially septoria leaf blotch Zymoseptoria tritici.[5]
Pydiflumetofen has fungicidal effects against a wide range of crop pests. These include Alternaria, grey mould (Botrytis cinerea), Cercospora (leaf spot), septoria, powdery mildews (e.g. Uncinula necator), and scab (e.g. Venturia pyrina). As a result, it has potential use in crops including cereals, corn, soybeans, vegetables, peanut, curcubits, potato and fruit.[13][14][15]
The compound was introduced in the US in 2018 but estimated usage that year was low at only 4,000 pounds (1,800 kg).[16] The compound is registered for use on peanut and fruits.[15] As of 2023[update] the compound is also registered in Argentina, Australia, Canada and New Zealand.[17]
Human safety
Pydiflumetofen has low acute toxicity:[12]: 8 the Codex Alimentarius database maintained by the FAO lists the maximum residue limits for it in various food products.[18]
Environmental effects
The compound is very persistent in field conditions and its environmental fate and consequent ecotoxicology have been reviewed.[12]: 11–15 In one laboratory study, the Renantiomer of the compound was shown to be more toxic to zebrafish, which was interpreted to be owing to its higher potency as an SDHI inhibitor than the S isomer.[19][20]
Resistance management
Fungal populations have the ability to develop resistance to SDHI inhibitors.[21] This potential can be mitigated by careful management. Reports of individual pest species becoming resistant[1] are monitored by manufacturers, regulatory bodies such as the EPA and the Fungicides Resistance Action Committee (FRAC).[22] The risks of resistance developing can be reduced by using a mixture of two or more fungicides which each have activity on relevant pests but with unrelated mechanisms of action. FRAC assigns fungicides into classes so as to facilitate this.[23]
Brands
Pydiflumetofen is the ISOcommon name[24] for the active ingredient which is formulated into the branded product sold to end-users. Miravis is the brand name for Syngenta's suspension concentrate, which it also calls Adepidyn technology.[15][17] The Miravis brand line includes other products containing pydiflumetofen mixed with other fungicidal active ingredients. These include Miravis Duo and Miravis Top (containing difenoconazole), Miravis Neo (containing propiconazole and azoxystrobin), and Miravis SBX (containing difenoconazole and azoxystrobin).[25]
Trebuset is the brand name for Syngenta's flowable concentrate formulation for use as a seed treatment.[26]
References
^ abPesticide Properties Database. "Pydiflumetofen". University of Hertfordshire.
^ abcWalter, Harald (2016). "Fungicidal Succinate-Dehydrogenase-Inhibiting Carboxamides". In Lamberth, Clemens; Dinges, Jürgen (eds.). Bioactive Carboxylic Compound Classes: Pharmaceuticals and Agrochemicals. Wiley. pp. 405–425. doi:10.1002/9783527693931.ch31. ISBN978-3-527-33947-1.
