Agriculture: Apple Pest Management Guidelines

General Properties of Fungicides Used in Apples

Common name
(trade name)
Chemical class Activity Mode of action
(FRAC number)1
Resistance potential Comments
bordeaux inorganic contact multi-site (M1) low  
captan phthalamide contact multi-site (M4) low highly toxic to honey bee larvae
copper inorganic contact multi-site (M1) low  
cyprodinil (Vangard) anilinopyrimidine mostly contact single-site (9) high  
fenarimol (Rubigan) DMI2-triazole systemic (local) single-site (3) high  
kresoxim-methyl (Sovran) strobilurin contact and systemic (local) single-site (11) high  
mancozeb (Dithane) carbamate EBDC3 contact multi-site (M3) low  
mefenoxam (Ridomil Gold) acylalanine contact and systemic single-site (4) high  
myclobutanil (Rally) DMI2-triazole systemic (local) single-site (3) high  
pyrimethanil (Scala) anilinopyrimidine mostly contact single-site (9) high  
sulfur inorganic contact multi-site (M2) low highly toxic to native strains of western predatory mite (Galendromus occidentalis) and to parasites
thiophanate-methyl (Topsin-M) benzimidazole systemic (local) single-site (1) very high  
trifloxystrobin (Flint) stroblilurin contact and systemic single-site (11) high  
triflumizole (Procure) DMI2-imidazole systemic (local) single-site (3) high  
ziram carbamate (DMDC) 4 contact multi-site (M3) low  
1 Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions. Fungicides with a different group number are suitable to alternate in a resistance management program. In California, make no more than one application of fungicides with mode-of-action Group numbers 1, 4, 9, 11, or 17 before rotating to a fungicide with a different mode-of-action Group number; for fungicides with other Group numbers, 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 EBDC = ethylene bisdithiocarbamate
4 DMDC = dimethyl dithiocarbamate

Acknowledgment: Adaskaveg et al., 2017. Efficacy and Timing of Fungicides, Bactericides, and Biologicals for Deciduous Tree Fruit, Nut, Strawberry, and Vine Crops (PDF).

Text Updated: 03/09