Agriculture: Apricot Pest Management Guidelines

General Properties of Fungicides

Caution: Never apply sulfur to apricot trees or captan to apricot fruit.

Common name
(Example trade name)
Chemical class Activity Mode of action
(FRAC Group No.1)
Resistance potential Comments
azoxystrobin (Abound) QoI2 contact,  systemic8 single-site (11) high9
captan phthalamide contact multi-site (M4) low highly toxic to
honey bee larvae
chlorothalonil (Bravo, etc.) chloronitrile contact multi-site (M5) low
copper10 inorganic contact multi-site (M1) low
copper -bordeaux inorganic contact multi-site (M1) low
cyprodinil (Vangard) anilinopyrimidine mostly contact, slight systemic single-site (9) high9
dicloran (Botran) aromatic hydrocarbon contact, slightly
systemic8
single-site (14) medium
difenoconazole/cyprodinil (Inspire Super) DMI4-triazole/ anilinopyrimidine contact,  systemic8 single-site/single-site
(3/9)
medium–high
difenoconazole/azoxystrobin (Quadris Top) DMI4-triazole/QoI2 contact, systemic (local)8 single-site/single-site
(3/11)
medium
fenbuconazole (Indar) DMI4-triazole systemic (local)8 single-site (3) high
fenhexamid (Elevate) hydroxyanilide contact single-site (17) high9
fludioxonil (Scholar) phenylpyrrole contact single-site
(oligo-site) (12)
medium postharvest fruit treatment
fosetyl-al (Aliette) ethyl phosphonates systemic unknown (P07, 33) low
iprodione (Rovral, Nevado, Iprodione) dicarboximide systemic (local) single site (2) low–medium highly toxic to
honey bee larvae
mefenoxam (Ridomil Gold) phenylamide contact, systemic single-site (4) high 9
metconazole (Quash) DMI4-triazole systemic (local)8 single-site (3) high
myclobutanil (Rally) DMI4-triazole systemic (local)8 single-site (3) high
penthiopyrad (Fontelis) SDHI7 contact single-site (7) high9
potassium phosphitephosphorous acid (ProPhyt, Fungi-Phite) phosphorous acid and salts systemic unknown (multi-site?) (P07, 33) medium3
propiconazole (Bumper ES, Tilt) DMI4-triazole systemic (local)8 single-site (3) high
propiconazole/azoxystrobin (Quilt Xcel) DMI4-triazole/
QoI2
systemic (local)8 single-site/single-site
(3/11)
medium
pyraclostrobin/boscalid (Pristine) QoI2 /SDHI7 contact, systemic8 single-site/single-site
(11/7)
medium–high
pyraclostrobin/fluxapyrozad (Merivon) QoI2 /SDHI7 contact, systemic8 single-site/single-site
(11/7)
medium–high  
pyrimethanil (Scala) anilinopyrimidine mostly contact, slight systemic single-site (9) high9
quinoxyfen (Quintec) quinoline contact single-site (13) medium–high
tebuconazole (Tebucon, Toledo) DMI4-triazole systemic (local)8 single-site (3) high
thiophanate-methyl (Topsin M) MBC5 systemic (local) single-site (1) high–very high9
trifloxystrobin (Gem) Qol2 contact, systemic8 single-site (11) high9
ziram carbamate (DMDC6) contact multi-site (M3) low highly toxic to
honey bee larvae
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 SAR = systemic acquired resistance induced in host
4 DMI = demethylation (sterol) inhibitor
5 MBC= methyl benzimidazole carbamate
6 DMDC = dimethyl dithiocarbamate
7 SDHI = succinate dehydrogenase inhibitor
8 Unsure or lacking scientific evidence. For fungicides, this indicates general acceptance of systemic action based on performance data, but this characteristic may not have been proven experimentally using more rigorous assays (e.g., radioactively labeled compounds).
9 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.
10 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).

Acknowledgment: Adaskaveg et al., 2022. Fungicides, Bactericides, Biocontrols, Biocontrols, and Natural Products for Deciduous Tree Fruit and Nut, Citrus, Strawberry, and Vine Crops in California.(PDF)

Text Updated: 10/14