Insecticide, acaricide Flufenoxuron

NOMENCLATURE Flufenoxuron

Common name flufenoxuron (BSI, draft E-ISO, (m) draft F-ISO)

IUPAC name 1-[4-(2-chloro-a,a,a-trifluoro-p-tolyloxy)-2-fluorophenyl]-3-(2,6-difluorobenzoyl)urea 

Chemical Abstracts name N-[[[4-[2-chloro-4-(trifluoromethyl)phenoxy]-2-fluorophenyl]amino]carbonyl]-2,6-difluorobenzamide 

CAS RN [101463-69-8] Development codes WL 115 110 (Shell); SKI-8503 

PHYSICAL CHEMISTRY Flufenoxuron

Composition Tech. grade is 98-100% pure. Mol. wt. 488.8 M.f. C₂₁H₁₁ClF₆N₂O₃ Form Tech. is a white, crystalline solid. M.p. 169-172 ºC (decomp.) V.p. 6.52 ´ 10^-9 mPa (20 ºC) K_OW logP = 4.0 (pH 7) S.g./density 1.57 kg/l (20 ºC) (typical value) Solubility In water 7 ´ 10^-11 g/l (pH 7, 15 ºC), 4 mg/l (25 ºC). In acetone 82, xylene 6, dichloromethane 24 (all in g/l, 25 ºC). Stability Stable £190 ºC; to natural sunlight; thin film on glass stable >100 h in simulated sunlight. DT₅₀ 11 d (ambient in water). On hydrolysis (25 ºC), DT₅₀ 206 d (pH 5), 267 d (pH 7), 36.7 d (pH 9), 2.7 d (pH 12). F.p. Not autoflammable; no explosive properties 

APPLICATIONS Flufenoxuron

Biochemistry Chitin synthesis inhibitor. Mode of action Insect and acarid growth regulator with contact and stomach action. Treated larvae die at the next moult or during the ensuing instar. Treated adults lay non-viable eggs. Uses Control of immature stages of many phytophagous mites (Aculus, Brevipalpus, Panonychus, Phyllocoptruta, Tetranychus spp.) and insect pests on pome fruit, vines, citrus fruit, tea, cotton, maize, soya beans, vegetables and ornamentals. Phytotoxicity None recorded. Formulation types EC; DC; DG. Selected tradenames: 'Cascade' (BASF)

MAMMALIAN TOXICOLOGY Flufenoxuron

Oral Acute oral LD₅₀ for rats >3000 mg tech./kg. Skin and eye Acute percutaneous LD₅₀ for rats and mice >2000 mg/kg. Non-irritating to eyes and skin (rabbits). Inhalation LC₅₀ (4 h) for rats 5 mg/l air. NOEL (1 y) for dogs 100 mg/kg diet; (90 d) for rats and mice 50 mg/kg diet. Toxicity class WHO (a.i.) III (Table 5); EPA (formulation) III 

ECOTOXICOLOGY Flufenoxuron

Birds Acute oral LD₅₀ for bobwhite quail >2000 mg/kg. Fish LC₅₀ (96 h) for rainbow trout >100 mg/l. Other beneficial spp. Low hazard to predatory mites and other predatory and parasitic arthropods. 

ENVIRONMENTAL FATE Flufenoxuron

Soil/Environment Strongly adsorbed in soil, DT₅₀ 42 d (clay loam). Use in orchards over 3 years at a dose of 97.5 g/ha gave rise to low residues in soil which did not significantly affect soil organisms, including earthworms (J. M. Gilbert et al., Proc. Br. Crop Prot. Conf. - Pests Dis., 1992, 2, 805-810).