1. UC IPM
  2. Agriculture
  3. Nectarine
  4. General Properties of Fungicides Used in Nectarines
Agriculture: Nectarine Pest Management Guidelines

General Properties of Fungicides Used in Nectarines

Common name (example trade name) Chemical class Activity Mode of action (group number)1 Resistance potential Comments
azoxystrobin (Quadris, Abound discontinued) Qol2 contact, systemic single-site (11) high8  
Bordeaux inorganic contact multi-site (M 01) low  
captan phthalimide contact multi-site (M 04) low highly toxic to honey bee larvae
chlorothalonil (Bravo) chloronitrile contact multi-site (M 05) low  
copper inorganic contact multi-site (M 01) low  
cyprodinil (Vangard) anilinopyrimidine contact, systemic on some crops single-site (9) high8  
dicloran (Botran**) aromatic hydrocarbon contact, systemic7 single-site (14) medium  
dodine (Syllit) guanidine systemic (local) unknown (U 12) medium  
fenbuconazole (Indar) DMI3-triazole systemic7 (local) single-site (3) high  
fenhexamid (Elevate) hydroxyanilide contact single-site (17) high8  
fosetyl-al (Aliette) ethyl phosphonates systemic unknown (P07/33) low  
iprodione (Rovral) dicarboximide systemic (local) single-site? (2) low toxic to honey bee larvae
mefenoxam (Ridomil Gold) phenylamide contact, systemic single-site (4) high  
metconazole (Quash) DMI3-triazole systemic7 (local) single-site (3) high  
myclobutanil (Rally) DMI3-triazole systemic7 (local) single-site (3) high  
propiconazole (Bumper**, Tilt) DMI3-triazole systemic7 (local) single-site (3) high  
pyraclostrobin/boscalid (Pristine) Qol2/SDHI5 contact, systemic single-site/single-site (11/7) high  
pyrimethanil (Scala) anilinopyrimidine contact, systemic on some crops single-site (9) high8  
quinoxyfen (Quintec) quinoline contact single-site (13) high  
sulfur inorganic contact multi-site (M 02) low highly toxic to native strains of western predatory mite (Galendromus occidentalis) and to parasites
tebuconazole (Elite**) DMI3-triazole systemic7 (local) single-site (3) high  
tebuconazole/trifloxystrobin (Adament) DMI3-triazole/Qol2 contact, systemic7 (local) single-site/single-site (3/11) high  
thiophanate-methyl (Topsin) MBC6 systemic (local) single-site (1) high8  
thiram (Thiram Granuflo) carbamate (DMDC4) contact multi-site (M 03) low  
trifloxystrobin (Gem) Qol2 contact, systemic7 single-site (11) high8  
ziram carbamate (DMDC4) contact multi-site (M 03) low  
** Not registered, label withdrawn or inactive in California (maybe registered federally).
1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions (for more information see www.frac.info). 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 Qol = quinone outside inhibitor (strobilurin)
3 DMI = demethylation (sterol) inhibitor
4 DMDC = dimethyl dithiocarbamate
5 SDHI = Succinate dehydrogenase inhibitor
6 MBC = Methyl benzimidazole carbamate
7 Unsure or lacking scientific evidence. These fungicides are generally considered to have systemic action based on performance data, but may not have been proven using lab assays (e.g. radioactively labeled compounds).
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., 2025. Fungicides, Bactericides, Biocontrols, and Natural Products for Deciduous Tree Fruit and Nut, Citrus, Strawberry, and Vine Crops in California.

Text Updated: 07/24
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