| Common name (Example trade name) |
Chemical class (FRAC #)1 |
Activity | Mode of action | Resistance potential | Comments |
|---|---|---|---|---|---|
| azoxystrobin (Abound) | Qol5 (11) | contact, systemic | single-site | high6 | |
| azoxystrobin/difenoconazole (Quadris Top) | QoI5/DMI2-triazole (11/3) | contact, systemic (local) | single-site/single site | medium | |
| azoxystrobin/propiconazole (Quilt Xcel) | QoI5/DMI2-triazole (11/3) | contact, systemic (local) | single-site/single site | medium | |
| captan (Captan) | phthalimide (M4) | contact | multi-site | low | highly toxic to honey bee larvae |
| chlorothalonil (Bravo/etc.) | chloronitrile (M5) | contact | multi-site | low | |
| dicloran (Botran 75W) | aromatic hydrocarbon (14) | contact/systemic7 | single–site | medium | |
| fenarimol (Rubigan) | DMI2-pyrimidine (3) | systemic (local) | single-site | high | |
| fenbuconazole (Indar) | DMI2-triazole (3) | systemic (local) | single-site | high | |
| fenhexamid (Elevate) | hydroxyanilide (17) | contact | single-site | high6 | pre- and postharvest |
| fludioxonil (Scholar) | phenylpyrrole (12) | systemic (local) | single-site (oligo-site) | medium | postharvest on fruit |
| fluopyram/trifloxystrobin (Luna Sensation) | SDHI4/QoI5 (7/11) | contact, systemic | single-site/single site | medium to high | postharvest on fruit |
| fosetyl-al (Aliette) | ethyl phosphonate (P07,33) | systemic | unknown | low | |
| iprodione (Rovral/Nevado/) | dicarboximide (2) | systemic (local) | single-site? | low to medium | |
| mefenoxam (Ridomil Gold) | phenylamide (4) | contact, systemic | single-site | high6 | |
| metconazole (Quash) | DMI2-triazole (3) | systemic (local) | single-site | high | |
| myclobutanil (Rally) | DMI2-triazole (3) | systemic (local) | single-site | high | |
| penthiopyrad (Fontelis) | SDHI4 (7) | contact | single-site | high6 | |
| propiconazole (Bumper) | DMI2-triazole (3) | systemic (local) | single-site | high | pre- and postharvest |
| pyraclostrobin/boscalid (Pristine) | QoI5/SDHI4 (11/7) | contact, systemic | single-site/single-site | medium to high | |
| quinoxyfen (Quintec) | quinoline (13) | contact | single-site | medium to high | |
| sulfur | inorganic (M2) | contact | multi-site | low | highly toxic to native strains of western predatory mite (Galendromus occidentalis) and to parasites |
| tebuconazole (Elite) | DMI2-triazole (3) | systemic (local) | single-site | high | pre- and postharvest |
| tebuconazole/trifloxystrobin (Adament) | DMI2-triazole/QoI5 (3/11) | contact, systemic (local) | single-site/single-site | medium to high | |
| thiophanate-methyl (Topsin-M) | MBC3 (1) | systemic (local) | single-site | very high6 | |
| triflumizole (Procure) | DMI2-imidazole (3) | systemic (local) | single-site | high |
| 1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of action. Fungicides with a different mode-of-action group number are suitable to alternate in a resistance management program. In California, make no more than one application of fungicides with mode-of-actions group number 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 DMI = demethylation (sterol) inhibitor |
| 3 MBC = methyl benzimidazole carbamate |
| 4 SDHI = succinate dehydrogenase inhibitor |
| 5 QoI = quinone outside inhibitor (strobilurin) |
| 6 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. |
| 7 Unsure or lacking scientific evidence. For fungicides, this indicates general acceptance of systemic action based on performance data, but this characteristic may not have been proven experimentally using more rigorous assays (e.g., radioactively labeled compounds). |
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)