Agriculture: Almond Pest Management Guidelines

General Properties of Fungicides Used in Almonds

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)

Text Updated: 08/17