Cyflufenamid

Cyflufenamid is an oxime amide fungicide that inhibits the formation of haustoria, colonies, and spores of Blumeria graminis f.sp. tritici, a wheat-specialized pathogen, and prevents the germ tube elongation of Monilinia fructicola. It is used in studies related to powdery mildew and brown rot.

Cyflufenamid, applied at concentrations ranging from 0.01 to 100 ppm for 3-20 days, effectively inhibits the growth of hyphae in certain Ascomycetes and Deuteromycetes in vitro, with the highest activity against Monilinia fructicola (EC50 = 0.01 ppm). At concentrations of 1-100 ppm over 2-24 hours, cyflufenamid does not affect early spore germination or germ tube elongation in Monilinia fructicola but inhibits germ tube growth after 16 hours, causing structural damage by 24 hours. When exposed to 1 ppm for 24 hours, this compound induces ultrastructural changes in Monilinia fructicola hyphae, including loss of electron-dense materials in vacuoles, septal abnormalities, and hyphal rupture. In greenhouse conditions, cyflufenamid at 6.3-25 ppm for 10 days, post-inoculation, shows excellent residual activity against cucumber powdery mildew (Sphaerotheca cucubitae) on seedlings (Sagamihanjiro), providing 100% control at 12.5 ppm and 25 ppm, and 77% efficacy at 6.3 ppm. It also demonstrates superior systemic activity when applied to cucumber seedlings at 12.5-50 ppm and evaluated 10 days post-inoculation, with 100% efficacy at 25 ppm and 50 ppm, and 83% at 12.5 ppm for systemic transmission after 10 days. Cyflufenamid applied via root treatment for 5 days exhibits low translocation to leaves, achieving only 25% control at 50 ppm and 12.5 ppm, and 13% at 3.1 ppm in cucumber seedlings (Sagamihanjiro) with powdery mildew. Additionally, concentrations of 3.1-50 ppm over 10 days demonstrate strong vapor-phase activity, with inhibition zone diameters of 41 mm at 50 ppm, 38 mm at 12.5 ppm, and 33 mm at 3.1 ppm.