| Common name (Example trade name) | Chemical class1 |
Activity | Mode of action (FRAC1 No.) | Resistance potential |
Comments |
|---|---|---|---|---|---|
| azoxystrobin (Abound) | Qol2 | contact, systemic | single-site (11) | high10 | some populations of Fusicladium sp. (scab) and Alternaria sp. have been found to be resistant to QoI fungicides |
| azoxystrobin/difenoconazole (Quadris Top) | QoI2/DMI3-triazole | contact, systemic (local) |
single-site/single-site (3/11) | medium | |
| azoxystrobin/propiconazole (Quilt Xcel) | QoI2/DMI3-triazole | contact, systemic (local) |
single-site/single-site (3/11) | medium | |
| boscalid/pyraclostrobin (Pristine) | SDHI4//Qol2 | contact, systemic | single-site/single-site (7/11) | medium–high | some populations of Fusicladium sp. (scab) and Alternaria sp. have been found resistant to QoI2 and SDHI4 fungicides |
| captan | phthalimide | contact | multi-site (M4) | low–medium | highly toxic to honey bee larvae |
| chlorothalonil (Bravo, Echo) | chlorothalonil | contact | multi-site (M5) | low | |
| copper8 | inorganic | contact | multi-site (M1) | low | |
| cyprodinil (Vangard) | anilinopyrimidine | mostly contact, slightly systemic (on most crops) | single-site (9) | high10 | more effective in spring than summer |
| difenoconazole (Inspire) | DMI3-triazole | systemic (local) | single-site (3) | high | |
| difenoconazole/cyprodinil (Inspire Super) | DMI3/anilinopyrimidine | contact, systemic | single-site/single-site (3/9) | medium | |
| fenbuconazole (Indar) | DMI3--triazole | systemic (local) | single-site (3) | high | |
| fenhexamid (Elevate) | hydroxyanilide | contact | single-site (17) | high10 | |
| fluopyram/tebuconazole (Luna Experience) | DMI3-triazlole/SDHI4 | contact, systemic | single-site/single-site (3/7) | medium | some populations have been found resistant to SDHI4 fungicides |
| fluopyram/trifloxystrobin (Luna Sensation) | SDHI4/QoI2 | contact, systemic | single-site/single-site (7/11) | medium–high | some populations have been found resistant to QoI2 and SDHI4 fungicides |
| fosetyl-Al (Aliette) | ethyl phosphonates | systemic | unknown (P07, 33) | low–medium | |
| iprodione (Rovral, Nevado) | dicarboximide | systemic (local) | single-site? (2) | low | |
| mancozeb (Dithane, Manzate) | carbamate (EBDC) 5 | contact | multi-site (M3) | low | |
| mefenoxam (Ridomil Gold) | phenylamide | contact, systemic | single-site (4) | high10 | |
| metconazole (Quash) | DMI3-triazole | systemic (local) | single-site (3) | high | |
| myclobutanil (Laredo, Rally) | DMI3-triazole | systemic (local) | single-site (3) | high | |
| penthiopyrad (Fontelis) | SDHI4 | contact | single-site (7) | high10 | use in mixtures when possible |
| polyoxin-D (Ph-D, Oso) | chitin synthesis inhibitor | contact | single-site (19) | medium | |
| potassium phosphite, phosphorous acid (Prophyt, Fosphite) | Phosphorous acid and salts | systemic | unknown (multi-site?) (P07,33) | low–medium | |
| propiconazole (Tilt, Bumper, Propicure, Propiconazole) | DMI3-triazole | systemic (local) | single-site (3) | high | |
| pyraclostrobin/fluxapyroxad (Merivon) | SDHI4/QoI2 | contact, systemic | single-site/single-site (7/11) | medium–high | some populations have been found resistant to QoI2 and SDHI4 fungicides |
| pyrimethanil (Scala) | anilinopyrimidine | mostly contact, slightly systemic (on most crops) | single-site (9) | high10 | more effective in spring than summer |
| sulfur | inorganic | contact | multi-site (M2) | low | highly toxic to native strains of western predatory mite (Galendromus occidentalis) and to parasites |
| tebuconazole (Tebuzol, Tebucon, Toledo) | DMI-triazole | systemic (local) | single-site (3) | high | |
| tebuconazole/phosphite (Viathon) | DMI-triazole /phosphonate |
contact, systemic | single-site/multi-site? (3/P07,33) | medium | |
| thiophanate-methyl (Topsin-M, T-Methyl, Incognito) | MBC6 | systemic (local) | single-site (1) | very high10 | resistant populations do not decline in absence of thiophanate-methyl use. |
| trifloxystrobin (Gem) | Qol2 | contact, systemic | single-site (11) | high | |
| ziram | carbamate (DMDC)7 | contact | multi-site (M3) | low | |
| BIOLOGICALS9 | |||||
| Aureobasidium pullulans (Botector#) | biological-fungus | contact | (BM02) | low | |
| Bacillus amyloliquefaciens D747 (Double Nickel 55#) | biological-bacteria | contact | (BM02) | low | |
| Bacillus subtilis (Serenade#) | biological-bacteria | contact | (BM02) | low | |
| Streptomyces lydicus (Actinovate AG#) | biological-bacteria | contact | (BM02) | low | |
| Trichoderma harzianum (PlantShield#) |
biological-fungus | contact | (BM02) | 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 QoI = quinone outside inhibitor (strobilurin) |
| 3 DMI = demethylation (sterol) inhibitor |
| 4 SDHI = succinate dehydrogenase inhibitor |
| 5 EBDC = ethylene bisdithiocarbamate |
| 6 MBC = methyl benzimidazole |
| 7 DMDC = dimethyl dithiocarbamate |
| 8 Fixed copper (M1a) bactericides (e.g., Kocide, Badge, Nordox, and ChampION++) may cause phytotoxicity (russetting) when applied after full bloom. Other copper products (M1b) with lower metallic copper equivalent (i.e., MCE) such as copper complexes (e.g., Cueva, Copper Count-N, etc.) and copper sulfate pentahydrate (e.g., CS-2005, Phyton 27AG, etc.) have been reported to be less phytotoxic with applications following bloom because of lower MCE (see specific registrant label concerning product rates and number of times each material can be applied during the growing season). |
| 9 For some biologicals growth is required for inhibition of pathogen by antagonism or mycoparasitism. |
| 10 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. |
| ? Mode of action uncertain |
| # Acceptable for use on organically grown produce. |
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)