NOMENCLATURE
Common name deltamethrin (BSI, draft E-ISO); deltaméthrine ((f) draft F-ISO)
IUPAC name (S)-a-cyano-3-phenoxybenzyl (1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate
Roth: (S)-a-cyano-3-phenoxybenzyl (1R)-cis-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate
Chemical Abstracts name [1R-[1a(S*),3a]]-cyano(3-phenoxyphenyl)methyl 3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylate
Other names decamethrin* (rejected common name proposal) CAS RN [52918-63-5]; [52820-00-5] ((RS)- (1R)-cis- isomer pair) EEC no. 258-256-6 Development codes NRDC 161; RU 22 974 (Roussel Uclaf); AE F032640 (AgrEvo) Official codes OMS 1998
PHYSICAL CHEMISTRY
Composition Tech. produced industrially by Aventis contains ³98% deltamethrin (i.e. the single isomer). Mol. wt. 505.2 M.f. C22H19Br2NO3 Form Colourless crystals. M.p. 100-102 ºC V.p. 1.24 ´ 10-5 mPa (25 °C, gas saturation method) KOW logP = 4.6 (25 ºC) Henry 3.13 ´ 10-2 Pa m3 mol-1 (calc.) S.g./density Bulk density 0.55 g/cm3 (25 ºC) Solubility In water <0.2 mg/l (25 ºC). In dioxane 900, cyclohexanone 750, dichloromethane 700, acetone 500, benzene 450, dimethyl sulfoxide 450, xylene 250, ethanol 15, isopropanol 6 (all in g/l, 20 ºC). Stability Extremely stable on exposure to air. Stable £190 ºC. Under u.v. irradiation and in sunlight, a cis-trans isomerisation, splitting of the ester bond, and loss of bromine occur. More stable in acidic than in alkaline media; DT50 2.5 d (pH 9, 25 ºC). Specific rotation [a]D +61?(40 g/l benzene)
APPLICATIONS
Biochemistry Like all pyrethroids, prevents the sodium channels from functioning, so that no transmission of nerve impulses can take place. Mode of action Non-systemic insecticide with contact and stomach action. Fast-acting. Uses A potent insecticide, effective by contact and ingestion against a wide range of pests. Crop protection uses include: Coleoptera (2.5-7.5 g/ha), Heteroptera (5.0-7.5 g/ha), Homoptera (6.2-12.5 g/ha), Lepidoptera (5.0-21 g/ha) and Thysanoptera (5-10 g/ha) in cereals, citrus, cotton, grapes, maize, oilseed rape, soya beans, top fruit and vegetables. It controls Acrididae (5.0-12.5 g/ha), and is recommended against locusts. Soil surface sprays (2.5-5.0 g/ha) control Noctuidae. It is used against indoor crawling and flying insects (12.5 mg/m2) and pests of stored grain (0.25-0.5 g/t) and timber (Blattodea, Culicidae, Muscidae). Dip or spray (12.5-75 mg/l), and pour-on (0.75 mg/kg b.w.) applications give good control of Muscidae, Tabanidae, Ixodidae and other Acari on cattle, sheep and pigs, etc. Formulation types DP; EC; EG; EW; GR; HN; PO; SC; SL; TB; UL; WG; WP.
