Fluazinam

Fluazinam is a broad-spectrum fungicide used in agriculture. It is classed as a diarylamine and more specifically an arylaminopyridine. Its chemical name is 3-chloro-"N"-(3-chloro-2,6-dinitro-4-trifluoromethylphenyl)-5-trifluoromethyl-2-pyridinamine. The mode of action involves the compound being an extremely potent uncoupler of oxidative phosphorylation in mitochondria and also having high reactivity with thiols. It is unique amongst uncouplers in displaying broad-spectrum activity against fungi and also very low toxicity to mammals due to it being rapidly metabolised to a compound without uncoupling activity. It was first described in 1992 and was developed by researchers at the Japanese company Ishihara Sangyo Kaisha.
Uses.
Fluazinam is a protectant fungicide, but is neither systemic or curative. It acts by inhibiting the germination of spores and the development of infection structures. Although it has activity against many fungi, it is less potent against rusts and powdery mildew and as such has not been commercialised for use in cereal crops. It is widely used to control late blight ("P. infestans") in potato due to its activity against the zoospores of the pathogen which makes it particularly effective at controlling infection of the potato tubers. Despite its common usage to control late blight, there are no reports of resistance to fluazinam appearing in "P. infestans". Fluazinam is also used to control "Sclerotinia" on peanuts and turf, "Botrytis" on grapes and beans and clubroot in brassicas.
Toxicity.
The acute oral median lethal dose in rats is very low at over 5000 mg/kg due to the compound's reactivity with thiols. This reactivity can have negative consequences since repeated exposure can cause skin sensitization and dermatitis to develop in some individuals. Fluazinam also displays low toxicity to birds, bees and worms, but has a high toxicity to fish. The toxicity towards fish is considered to be relatively unimportant, since the compound has a very short half-life (around 1 day) in aquatic systems.