Agriculture: Citrus Pest Management Guidelines

General Properties of Fungicides Used in Citrus

Common name
(Example trade name)
Chemical class Activity Mode of action (Group number)1 Resistance potential Comments
PREHARVEST
azoxystrobin (Abound) Qol2 (strobilurin) local systemic single-site (11) high  
azoxystrobin/difenoconazole (Quadris Top) QoI2/DMI3 locally systemic multi-site (3/11) med. premixture
bordeaux inorganic contact multi-site (M1) low copper and lime based mixture that often includes a zinc adjuvant.
copper inorganic contact multi-site (M1) low fixed coppers (non-copper sulfate materials such as copper hydroxide and copper oxide)
fluopyram/trifloxystrobin (Luna Sensation) SDHI4/Qol2 locally systemic multi-site (7/11) low premixture
fluxapyroxad/pyraclostrobin (Priaxor) SDHI4/Qol2 locally systemic multi-site (7/11) low premixture
fosetyl-al (Aliette) phosphonate systemic multi-site (33) low resistant pathogen populations reported
hydrated lime inorganic contact multi-site (M1) low  
mefenoxam (Ridomil Gold) acylalanine systemic single-site (4) high  
oxathiapiprolin (Orondis) oxysterol binding proteins mostly contact single-site (U15) high  
oxytetracycline (Fireline) tetracycline antibiotic contact protein synthesis (41) high  
polyoxin-D (Tavano/Oso) polyoxin contact single-site (19) med. biopesticide
potassium phosphite (Fungi-Phite, Prophyt) phosphonate systemic multi-site (33) low biopesticide, resistant pathogen populations reported
streptomycin (Firewall) glucopyranosyl antibiotic systemic protein synthesis (25) high  
POSTHARVEST  
fludioxonil (Graduate) phenylpyrrole contact few (multi-site) (12) med.  
fludioxonil/azoxystrobin (Graduate A+) phenylpyrrole/ Qol2 (strobilurin) contact/ locally systemic few (multi-site) (11/12) med. premixture
imazalil (FungaFlor 500EC) DMI3 locally systemic single-site (3) high resistant pathogen populations reported
pyrimethanil (Penbotec) AP5 locally systemic single-site (9) high resistant pathogen populations reported
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 3, 4, 9, 11, 12, or 33, 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 QoI = Quinone outside inhibitor (strobilurin)
3 DMI = Demethylation inhibitors
4 SDHI = Succinate dehydrogenase inhibitors
5 AP = Anilino-pyrimidine
6 MBC = methylbenzimidazole carbamate
Text Updated: 01/19