Agriculture: Lettuce Pest Management Guidelines

General Properties of Fungicides

Common name
(Example trade name)
Chemical class Activity Mode of action
(FRAC number)1
Resistance Comments
acibenzolar-S-methyl (Actigard) BTH2 systemic — (P1) low
azoxystrobin (Quadris) QoI3 contact, systemic4 single-site (11) high
boscalid (Endura) SDHI5 contact, systemic4 single-site (7) medium to high
copper inorganic contact multi-site (M1) low
cyprodinil/fludioxonil (Switch) AP/PP6 multi-site (9/12) low
dicloran (Botran) AH7 locally systemic single-site (14) high
dimethomorph (Forum) CAA8 locally systemic single-site (40) low to medium
famoxadone/cymoxanil (Tanos) QoI3/cyanoacetamide-oximes —/systemic multi-site (11/27) low
fenamidone (Reason) QoI3 systemic4 single-site (11) high
fludioxonil (Cannonball) phenylpyrrole contact few to multi-site (12) medium
fluopicolide (Presidio) benzamide locally systemic single-site (43) low
fosetyl-Al (Aliette) phosphonate systemic multi-site (33) low
iprodione (Rovral) dicarboximide locally systemic multi-site (2) medium to high toxic to honey bee larvae; do not apply during bloom.
mancozeb (Mancozeb 75WDG) dithiocarbamate contact multi-site (M3) low
mandipropamid (Revus) CAA8 systemic single-site (40) low to medium
mefenoxam (Ridomil Gold) phenylamide systemic single-site (4) high
myclobutanil (Rally) triazole systemic single-site (3) medium
penthiopyrad (Fontelis) SDHI5 contact, systemic single-site (7) medium to high
phosphorus acid (Fosphite) phosphonate systemic multi-site (33) low
quinoxyfen (Quintec) quinoline single-site (13) medium
sulfur (Microthiol Disperss) inorganic contact multi-site (M2) low toxic to predatory mites and parasites.
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. For fungicides with mode-of-action group numbers 1, 4, 9, 11, or 17, make no more than one application 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 BTH = benzo-thiadiazole
3 QoI = quinone outside inhibitor (strobilurin)
4 Generally considered to have systemic action based on performance data but has not been proven experimentally.
5 SDHI = succinate-dehydrogenase inhibitor
6 AP/PP = anilinopyrimidine/phenylpyrrole
7 AH = aromatic hydrocarbon
8 CAA = carboxylic acid amide
No information

Acknowledgment: This information was adapted from the Fungicide Resistance Action Committee website.

Text Updated: 04/17