Acaricide, insecticide
amidine


NOMENCLATURE
Common name amitraz (BSI, E-ISO, ANSI, ESA, BAN, JMAF); amitraze ((m) F-ISO)
IUPAC name N-methylbis(2,4-xylyliminomethyl)amine 
Chemical Abstracts name N'-(2,4-dimethylphenyl)-N-[[(2,4-dimethylphenyl)imino]methyl]-N-methylmethanimidamide 
Other names N,N-bis(2,4-xylyliminomethyl)methylamine; N-methyl-N'-2,4-xylyl-N-(N-2,4-xylylformimidoyl)formamidine; 1,5-di-(2,4-dimethylphenyl)-3-methyl-1,3,5-triazapenta-1,4-diene  CAS RN [33089-61-1]  EEC no. 251-375-4  Development codes BTS 27 419 (Boots)  Official codes OMS 1820; ENT 27 967

PHYSICAL CHEMISTRY
Mol. wt. 293.4  M.f. C₁₉H₂₃N₃ Form White/pale yellow crystalline solid.  M.p. 86-88 ºC  V.p. 0.34 mPa (25 ºC) using clapeyron-clausius analysis  K_OW logP = 5.5 (25 ºC, pH 5.8)  Henry 1.0 Pa m³ mol-1 (measured)  S.g./density 1.128 (20 ºC)  Solubility In water <0 .1 mg/l (20 °C). Soluble in most organic solvents; in acetone, toluene, xylene >300 g/l.  Stability Hydrolysis DT50 (25 ºC) 2.1 h (pH 5), 22.1 h (pH 7), 25.5 h (pH 9). U.V. light appears to have little effect on stability.  pKa 4.2, weak base

APPLICATIONS
Biochemistry Mode of action probably involves an interaction with octopamine receptors in the tick nervous system, causing an increase in nervous activity.  Mode of action Non-systemic, with contact and respiratory action. Expellent action causes ticks to withdraw mouthparts rapidly and fall off the host animal.  Uses Control of all stages of tetranychid and eriophyid mites, pear suckers, scale insects, mealybugs, whitefly, aphids, and eggs and first instar larvae of Lepidoptera on pome fruit, citrus fruit, cotton, stone fruit, bush fruit, strawberries, hops, cucurbits, aubergines, capsicums, tomatoes, ornamentals, and some other crops. Also used as an animal ectoparasiticide to control ticks, mites and lice on cattle, dogs, goats, pigs and sheep.  Phytotoxicity At high temperatures, young capsicums and pears may be injured.  Formulation types EC; PO; WP.  Compatibility Incompatible with alkaline materials, parathion, and others.

ANALYSIS
Product analysis by glc (CIPAC Handbook, 1995, G, 5-10). Residue analysis also by glc. Details available from Aventis.

MAMMALIAN TOXICOLOGY
Reviews FAO/WHO 83, 85 (see part 2 of the Bibliography).  Oral Acute oral LD₅₀ for rats 650, mice >1600 mg/kg.  Skin and eye Acute percutaneous LD₅₀ for rabbits >200, rats >1600 mg/kg.  Inhalation LC₅₀ (6 h) for rats 65 mg/l air.  NOEL In 2 y feeding trials, no adverse effect observed in rats receiving 50-200 ppm diet, or in dogs dosed 0.25 mg/kg daily. Human NOEL >0.125 mg/kg daily.  ADI (JMPR) 0.01 mg/kg b.w. [1998].  Toxicity class WHO (a.i.) III; EPA (formulation) III  EC hazard Xn; R22

ECOTOXICOLOGY
Birds LD₅₀ for bobwhite quail 788 mg/kg. LC₅₀ (8 d) for mallard ducks 7000, Japanese quail 1800 mg/kg.  Fish LC₅₀ (96 h) for rainbow trout 0.74, bluegill sunfish 0.45 mg/l. Due to rapid hydrolysis, it is unlikely that this toxicity will be expressed in natural aquatic systems.  Daphnia LC₅₀ (48 h) 0.035 mg/l. Due to rapid hydrolysis, it is unlikely that this toxicity will be expressed in natural aquatic systems.  Algae EC₅₀ for Selenastrum capricornutum >12 mg/l.  Bees Low toxicity to bees and predatory insects. LD₅₀ (contact) 50 mg/bee (formulation).  Worms LC₅₀ (14 d) for earthworms >1000 mg tech./kg.

ENVIRONMENTAL FATE
Animals Rapid breakdown leading to excretion as a conjugate of 4-amino-3-methylbenzoic acid and, to a lesser extent, to N-(2,4-dimethylphenyl)-N'-methylformamidine.  Plants Rapidly degraded, mainly to N-(2,4-dimethylphenyl)-N'-methylformamidine and, to a smaller extent, to 2,4-dimethylformanilide.  Soil/Environment Rapidly broken down in soil under aerobic conditions (J. Appl. Bacteriol., 1977, 42, 187; ibid. 1978, 44, 383); DT₅₀ in soil <1 d. Degradation occurs more rapidly in acid than in neutral or alkaline soils. Very strongly adsorbed to soil; K_oc c. 1000-2000.