| Common name (example trade name) |
Chemical class (FRAC group number # )1 |
Activity | Mode of action | Resistance potential |
|---|---|---|---|---|
| azoxystrobin (Abound) | QoI2 (11) | contact, systemic | single-site | high7 |
| boscalid (Endura) | SDHI4 (7) | contact | single-site | high7 |
| cyprodinil (Vangard) | anilinopyrimidine (9) | mostly contact, slightly systemic (on most crops) | single-site | high7 |
| cyprodinil/fludioxonil (Switch) | anilinopyrimidine/phenylpyrrole (9/12) | contact, slightly systemic | single-site/single-site | medium to high |
| fenhexamid (Elevate) | hydroxyanilide (17) | contact | single-site | high7 |
| iprodione (Rovral) | dicarboximide (2) | systemic (local) | single-site? | medium |
| pyraclostrobin (Cabrio) | QoI2 (11) | contact, systemic | single-site | high7 |
| pyrimethanil (Scala) | anilinopyrimidine (9) | mostly contact, slightly systemic (on most crops) | single-site | high7 |
| Reynoutria sachalinensis extract | natural product (BM 01, P05) |
contact | various | low |
| tebuconazole (Elite) | DMI3-triazole (3) | systemic (local)6 | single-site | high |
| thiophanate-methyl (Topsin-M) | MBC5 (1) | systemic (local) | single-site | high to very high7 |
| trifloxystrobin (Gem) | Qol2 (11) | contact, systemic6 | single-site | high7 |
| 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 (strobilurin). |
| 3 DMI = demethylation (sterol) inhibitor. |
| 4 SDHI = succinate dehydrogenase inhibitor |
| 5 MBC = methyl benzimidazole carbamate |
| 6 Generally considered to have systemic action based on performance data but has not been proven experimentally. |
| 7 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)