| Common name (example trade name) |
Chemical class | Activity | Mode of action (FRAC group number1) |
Resistance potential | Comments |
|---|---|---|---|---|---|
| azoxystrobin (Abound) | QoI5 | contact, systemic2 | single-site (11) | high3 | |
| Bacillus pumilis (Sonata) | biological-bacteria | contact | BM 02 | low | |
| Bacillus subtilis (Serenade) | biological-bacteria | contact | BM 02 | low | |
| boscalid/pyraclostrobin (Pristine) | SDHI6 and Qol5 | contact, systemic2 | single-site/ single-site (11/7) |
high | |
| captan | phthalimide | contact | multi-site (M4) | low | highly toxic to honey bee larvae |
| copper | inorganic | contact | multi-site (M1) | low | |
| copper hydroxide | inorganic | contact | multi-site (M1) | low | |
| copper sulfate | inorganic | contact | multi-site (M1) | low | |
| cyflufenamid (Torino) | phenylacetamide | contact | unknown (U6) | high | |
| cyprodinil (Vangard) | anilinopyrimidine | mostly contact, slightly systemic (on most crops) | single-site (9) | high3 | |
| cyprodinil/fludioxonil (Switch) | anilinopyrimidine and phenylpyrrole | contact, slightly systemic | single-site/ single-site (9/12) |
low to medium | |
| difenoconazole/azoxystrobin (Quadris Top) | DMI4-triazole and QoI5 | contact and systemic (local) 2 | single-site/ single-site (3/11) |
medium to high | |
| difenoconazole/cyprodinil (Inspire Super) | DMI4 and anilinopyrimidine | contact, systemic2 | single-site/ single-site (3/9) |
medium | |
| fenhexamid (Elevate) | hydroxyanilide | Contact | single-site (17) | high3 | |
| fluopyram/tebuconazole (Luna Experience) | SDHI6 pyridinyl-ethyl-benzamide and DMI4 | contact, systemic2 | single-site/ single-site (7/3) |
medium | |
| fungicidal soap (M-Pede) | inorganic salt | Contact | — | low | |
| iprodione (Rovral) | dicarboximide | systemic (local) | single-site? (2) | low to medium | |
| kresoxim-methyl (Sovran) | Qol5 | contact, systemic2 | single-site (11) | high3 | |
| mancozeb (Dithane) | dithiocarbamate | contact | multi-site (M3) | low | |
| mefenoxam (Ridomil Gold) | phenylamide | contact, systemic | single-site (4) | high3 | |
| metrafenone (Vivando) | benzophenone | contact | singe-site (50) | high | |
| myclobutanil (Rally) | DMI4-triazole | systemic (local)2 | single-site (3) | high | |
| oil (JMS stylet oil) | mineral oil | contact | various (NC) | low | |
| potassium bicarbonate (Armicarb, Kaligreen, Milstop) | inorganic salt | contact | various (NC) | low | |
| pyrimethanil (Scala) | anilinopyrimidine | mostly contact, slightly systemic (on most crops) | single-site (9) | high3 | |
| quinoxyfen (Quintec) | quinoline | contact | single-site (13) | medium to high | |
| sulfur | inorganic | contact | multi-site (M2) | low | highly toxic to native strains of western predatory mite (Galen-dromus occidentalis) and parasites. |
| tebuconazole (Elite) | DMI4-triazole | systemic (local)2 | single-site (3) | high | |
| tetraconazole (Mettle) | DMI4-triazole | systemic (local)2 | single-site (3) | high | |
| thiophanate-methyl (Topsin) | MBC7 | systemic (local) | single-site (1) | very high3 | |
| trifloxystrobin (Flint) | Qol5 | contact, systemic2 | single site (11) | high3 | |
| triflumizole (Procure) | DMI4-imidazole | systemic (local)2 | single-site (3) | high | |
| ziram | dithiocarbamate | contact | multi-site (M3) | low |
| 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 Generally considered to have systemic action based on performance data but this characteristic may not have been proven experimentally using more rigorous assays. |
| 3 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. |
| 4 DMI = demethylation (sterol) inhibitor |
| 5 Qol = quinone outside inhibitor (strobilurin) |
| 6 SDHI = succinate dehydrogenase inhibitor |
| 7 MBC = methyl benzimidazole carbamate |
| — = unknown |
| NC = not classified |
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)