Acaricide

NOMENCLATURE

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

IUPAC name (4RS,5RS)-5-(4-chlorophenyl)-N-cyclohexyl-4-methyl-2-oxo-1,3-thiazolidine-3-carboxamide 

Chemical Abstracts name trans-5-(4-chlorophenyl)-N-cyclohexyl-4-methyl-2-oxo-3-thiazolidinecarboxamide 

CAS RN [78587-05-0]  Development codes NA-73 (Nippon Soda) 

PHYSICAL CHEMISTRY

Mol. wt. 352.9  M.f. C17H21ClN2O2S  Form Colourless crystals.  M.p. 108.0-108.5 ºC  V.p. 0.0034 mPa (20 ºC)  KOW logP = 2.53  Henry 2.40 ´ 10-3 Pa m3 mol-1 (calc.)  Solubility In water 0.5 mg/l (20 ºC). In chloroform 1379, xylene 362, methanol 206, acetone 160, acetonitrile 28.6, hexane 4 (all in g/l, 20 ºC).  Stability Stable to light, air and heat, and in acidic and alkaline media. Stable to 300 ºC. Aqueous solution in sunlight DT50 16.7 d. 

COMMERCIALISATION

History Acaricide reported by T. Yamada (Proc. Int. Congr. Pestic. Chem., Kyoto, 5th, 1982), see also Jpn. Pestic. Inf., 1984, No. 44, p. 21. Introduced by Nippon Soda Co., Ltd. Registered in Japan in 1985.  Patents GB 2059961; US 4442116  Manufacturers Nippon Soda

APPLICATIONS

Mode of action Non-systemic acaricide with contact and stomach action. Good translaminar activity. Has ovicidal, larvicidal, and nymphicidal activity. Not active against adults, but eggs laid by treated females are non-viable.  Uses Control of eggs and larvae of many phytophagous mites (particularly Panonychus, Tetranychus, and Eotetranychus spp.) on fruit, citrus, vegetables (all at 150-300 g/ha), vines and cotton.  Formulation types EC; FU; WP.  Selected tradenames: 'Nissorun' (Nippon Soda); 'Cesar' (Aventis); 'Hexygon' (Gowan); 'Matacar' (Sipcam); 'Ordoval' (BASF); 'Savey' (Gowan); 'Zeldox' (Syngenta)

OTHER TRADENAMES

'Acarflor' (Sipcam); 'Calibre' (BASF); 'Stopper' (Aventis)

ANALYSIS

Product and residue analysis by hplc (M. Tokieda et al., J. Pestic. Sci., 1987, 12, 711). 

MAMMALIAN TOXICOLOGY

Reviews FAO/WHO 62, 64 (see part 2 of the Bibliography).  Oral Acute oral LD50 for rats and mice >5000 mg/kg.  Skin and eye Acute percutaneous LD50 for rats >5000 mg/kg. Mild eye irritant; non-irritating to skin (rabbits). Non-sensitising to skin (guinea pigs).  Inhalation LC50 (4 h) for rats >2 mg/l air.  NOEL (2 y) for rats 23.1 mg/kg b.w.; (1 y) for dogs 2.87 mg/kg b.w.; (90 d) for rats 70 mg/kg diet.  ADI (JMPR) 0.03 mg/kg [1991].  Other Non-teratogenic. Not mutagenic in the Ames assay.  Toxicity class WHO (a.i.) III (Table 5); EPA (formulation) IV  EC hazard N; R50, R53 

ECOTOXICOLOGY

Birds Acute oral LD50 for mallard ducks >2510, Japanese quail >5000 mg/kg. Dietary LC50 (8 d) for mallard ducks and bobwhite quail >5620 mg/kg diet.  Fish LC50 (96 h) for rainbow trout >300, bluegill sunfish 11.6 mg/l; (48 h) for carp 3.7 mg/l.  Daphnia LC50 (48 h) 1.2 mg/l.  Bees Not toxic to bees. LD50 by topical application >200 mg/bee. 

ENVIRONMENTAL FATE