Agriculture: Pear Pest Management Guidelines

General Properties of Fungicides Used in Pears

Common name
(example trade name)
Chemical class Activity Mode of action (FRAC number)1 Resistance potential Comments
Aureobasidium pullulans (Blossom Protect) biological—fungus contact various (BM 02) low
Bacillus subtilis (Serenade Max) biological—bacteria contact various (BM 02) low
Bordeaux inorganic contact multi-site (M1) low
copper9 inorganic contact multi-site (M1) low
cyprodinil (Vangard) anilinopyrimidine mostly contact, slightly systemic (on most crops) single-site (9) high10
difenoconazole/cyprodinil (Inspire Super) DMI2-triazole/
contact, systemic single-site/single-site (3/9) medium
dodine (Syllit) guanidine systemic (local) unknown (U12) medium slow resistance by limiting applications to one per season or tank mixing with another fungicide
fenarimol (Rubigan, Vintage) DMI2-pyrimidine systemic8 (local) single-site (3) high
fosetyl-al (Aliette) ethyl phosphonates systemic unknown (P07, 33) low
kresoxim-methyl (Sovran) QoI3 contact, systemic8 single-site (11) high10
lime sulfur inorganic contact multi-site (M2) low incompatible with most other pesticides
mancozeb (Dithane, Penncozeb, Manzate) carbamate (EBDC)4 contact multi-site (M3) low
oxytetracycline (Mycoshield, Fireline) antibiotic contact protein synthesis (41) high
Pseudomonas fluorescens (Blight Ban) biological—bacteria contact various (BM 02) low
pyraclostrobin/boscalid (Pristine) Qol3/SDHI7 contact, systemic single-site/single site (11/7) medium to high
pyrimethanil (Scala) anilinopyrimidine mostly contact, slightly systemic (on most crops) single-site (9) high10
Agri-Mycin, Firewall)
antibiotic systemic protein synthesis (25) high to very high
sulfur inorganic contact multi-site (M2) low toxic to predatory mites and parasites
tebuconazole (Tebuzol) DMI2-triazole2 systemic8 (local) single-site (3) high
tebuconazole/trifloxystrobin (Adament) DMI2-triazole/Qol3 contact, systemic8 single-site/single-site (3/11) medium
thiophanate-methyl (Topsin-M, T-Methyl, Incognito) MBC6 systemic (local) single-site (1) high to very high10 toxic to earthworms with repeated usage
trifloxystrobin (Flint) QoI3 contact, systemic8 single-site (11) high10
triflumizole (Procure) DMI2-imidazole systemic8 (local) single-site (3) high
ziram carbamate (DMDC)5 contact multi-site (M3) 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 DMI = demethylation (sterol) inhibitor
3 QoI = quinone outside inhibitor (strobilurin)
4 EBDC = ethylene bisdithiocarbamate
5 DMDC = dimethyl dithiocarbamate
6 MBC = methyl benzimidazole carbamate
7 SDHI = succinate dehydrogenase inhibitor
8 Unsure or lacking scientific evidence. For fungicides, a question mark 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 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).
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.
— = No information

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: 06/17