| Common name (Example trade name) |
Chemical class1 | Mode of action (FRAC1 group number) |
Activity | Resistance potential | Comments |
|---|---|---|---|---|---|
| azoxystrobin/difenoconazole (Quadris Top) | QoI2/DMI3-triazole | single-site/single-site (11/3) | contact, systemic (local) | medium | |
| azoxystrobin/propiconazole (Quilt Xcel) | QoI2/DMI3-triazole | single-site/single-site (11/3) | contact, systemic (local) | medium | |
| copper | inorganic | multi-site (M1) | contact | low | |
| difenoconazole/cyprodinil (Inspire Super) |
DMI3-triazole /AP7 | single-site/single-site (3/9) | contact, systemic | medium | |
| fluopyram/tebuconazole (Luna Experience) |
SDHI4 | single-site/single-site (7/3) | contact, systemic | medium | |
| fluopyram/trifloxystrobin (Luna Sensation) |
SDHI4/QoI2 | single-site/single-site (7/11) | contact, systemic (local) | medium to high | |
| flutriafol (Rhyme) | DMI3-triazole | single-site (3) | systemic (local) | high | |
| mancozeb (Dithane, Manzate) | carbamate (EBDC) 5 | multi-site (M3) | contact | low | |
| mefenoxam (Ridomil Gold) | phenylamide | single-site (4) | contact, systemic | high8 | |
| metconazole (Quash) | DMI3-triazole | single-site (3) | systemic (local) | high | |
| penthiopyrad (Fontelis) | SDHI4 | single-site (7) | contact | high8 | |
| phosphorous acid (Fosphite) | phosphorous acid and salts | unknown, multi-site? (P 07, 33) | systemic | medium | |
| polyoxin-D (Ph-D) | chitin synthesis inhibitor |
single-site (19) | contact | medium | |
| pyraclostrobin/boscalid (Pristine) |
Qol2/SDHI4 | single-site/single-site (11/7) | contact, systemic (local) | medium to high | |
| pyraclostrobin/fluxapyroxad (Merivon) | Qol3/SDHI4 | single-site/single-site (11/7) | contact, systemic | medium to high | |
| tebuconazole (Tebuzol) | DMI3-triazole | single-site (3) | systemic (local) | high |
| 1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of action. Fungicides with different group numbers are suitable to alternate in a resistance management program. In California, make no more than one application of a fungicide with a mode-of-action group number associated with high resistance risk before rotating to a fungicide with a different mode-of-action group number; for other fungicides, make no more than two consecutive applications before rotating to fungicide with a different mode-of-action group number. |
| 2 QoI = quinone outside inhibitor or strobilurin |
| 3 DMI = demethylation (sterol) inhibitor |
| 4 SDHI = succinate dehydrogenase inhibitor |
| 5 EBDC = ethylene bisdithiocarbamate |
| 6 MBC = methyl benzimidazole carbamate |
| 7 AP = anilinopyrimidine |
| 8 Resistance has been found in California for certain fungicides with a single-site mode of action. To reduce the risk of resistance development, take the mode of action into account when choosing a fungicide. At the beginning of a treatment program, use a fungicide with a multi-site mode of action; for subsequent applications rotate or mix fungicides with different mode of action FRAC numbers. Use labeled rates (preferably the upper range) of the single-site fungicides, and limit the total number of applications per season. |
Acknowledgment: Adaskaveg et al., 2022. Fungicides, Bactericides, Biocontrols, and Natural Products for Deciduous Tree Fruit and Nut, Citrus, Strawberry, and Vine Crops in California. (PDF)