Fungicide Use in Field Crops: Web Book

1.4: Fungicide Resistance Action Committee (FRAC) Code

1.4: Fungicide Resistance Action Committee (FRAC) Code

The Fungicide Resistance Action Committee (FRAC) is an international consortium of fungicide manufacturers that provides information regarding fungicide resistance mitigation. The organization has created a code useful for easy classification of fungicides based on their cross-resistance behavior. Every fungicide label displays a FRAC code which consists of numbers and letters (Table 1.4).

Table 1.4. Examples of fungicide classification and resistance risk for fungicides available for use on field crops.

FRAC code Mode of action Target site of action Group name Active ingredient common name Risk of resistance
1 Cytoskeleton and motor protein Mitosis and cell division (ß-tubulin assembly) Methyl Benzimidazole Carbamates (MBC) Thiabendazole High
Thiophanate-methyl
2 Signal transduction MAP/Histidine-kinase in osmotic signal transduction in os-1, Daf1 genes Dicarboximides Iprodione Medium to high
Vinclozolin
3 Membrane sterol biosynthesis  C14 - demethylation in sterol biosynthesis Demethylation Inhibitors (DMI)¹  Cyproconazole Medium
Difenoconazole
Fenbuconazole
Flutriafol
Imazalil
Metconazole
Myclobutanil
Propiconazole
Prothioconazole
Tebuconazole
Tetraconazole
Triticonazole
4 Nucleic acid metabolism RNA polymerase 1 Phenylamides Mefenoxam High
Metalaxyl
7 Respiration inhibitor Complex II: succinate-dehydrogenase Succinate Dehydrogenase Inhibitors (SDHI)²  Benzovindiflupyr Medium to high
Boscalid
Carboxin
Fluopyram
Flutolanil
Fluxapyroxad
Penthiopyrad
Pydiflumetofen
Sedaxane
9 Amino acid and protein synthesis Methionine Anilino-pyrimidines (AP) Cyprodinil Medium
Biosynthesis (proposed) Pyrimethanil
11 Respiration inhibitor Complex III: cytochrome bc1, Qo site Quinone Outside Inhibitors (QoI)³ Azoxystrobin High
Famoxadone
Fenamidone
Fluoxastrobin
Picoxystrobin
Pyraclostrobin
Trifloxystrobin
12 Signal transduction MAP/Histidine-kinase in osmotic signal transduction in os-2, HOG1 genes Phenylpyrroles (PP) Fludioxonil Low to medium
14 Lipid synthesis, transport, or membrane function Cell peroxidation (proposed) Aromatic Hydrocarbons Chloroneb Low to medium
Quintozene (PCNB)
21 Respiration inhibitor Complex III: cytochrome bc1, Qi site Quinone Inside Inhibitors (QiI) Cyazofamid Medium to high
22 Cytoskeleton and motor protein Mitosis (Beta-tubulin assembly) Thiazole carboxamide Ethaboxam Low to medium
27 Unknown Unknown Cyanoacetamide-oximes Cymoxanil Low to medium
28 Lipid synthesis, transport or membrane function Cell membrane permeability, fatty acids (proposed) Carbamates Propamocarb Low to medium
29 Respiration inhibitor Uncoupler of oxidative phosphorylation Oxidative Phosphorylation Uncouplers Fluazinam Low
30 Respiration inhibitor Inhibits oxidative phosphorylation, ATP synthase Organo Tin Compounds Fentin hydroxide Low to medium
(Triphenyltin hydroxide)
32 Nucleic acid metabolism DNA/RNA synthesis (proposed) Heteroaromatics Hymexazol Not known
40 Cell wall biosynthesis Cellulose synthase Carboxylic Acid Amides (CAA) Dimethomorph Low to medium
Mandipropamid
44 Lipid synthesis, transport, or membrane function Microbial disrupters of pathogen cell membranes Microbial Bacillus amyloliquefaciens (several strains) Not known
49 Lipid synthesis, transport, or membrane function Lipid homeostasis and transfer/storage Oxysterol Binding Protein Homologue Inhibition Oxathiapiprolin Medium to high
M 01 Multi-site Multi-site, contact Inorganic  Copper Low
M 03 Multi-site Multi-site, contact Dithiocarbamates and Relatives Mancozeb Low
Maneb
Thiram
M 04 Multi-site Multi-site, contact Phthalimides Captan Low
M 05 Multi-site Multi-site, contact Chloronitriles Chlorothalonil Low
P 07 (33) Host plant defense induction Phosphonates Phosphonates Phosphorous acid and salts Low

¹Some fungicides in the DMI group are commonly referred to as "triazoles." ²Some of the succinate dehydrogenase inhibitor fungicides may be referred to as “carboxamides.” ³Some fungicides in the QoI group may be referred to as "strobilurins." 

Earn a Certified Crop Advisor CEU after reading this chapter. Successfully complete the Chapter 1 quiz for one CEU. Each chapter has a corresponding quiz at Crop Protection Network CCA CEU page.

Click the link below to download this publication.

1.4: Fungicide Resistance Action Committee (FRAC) Code