Pesticides >> Insecticides >> Dicamba

Dicamba

Dicamba 98%TC
Dicamba 48%SL

Herbicide
HRAC O WSSA 4; benzoic acid (auxin)

NOMENCLATURE
dicamba
Common name dicamba (BSI, E-ISO, (m) F-ISO, ANSI, WSSA); dianat* (former exception, USSR); MDBA (JMAF)
IUPAC name 3,6-dichloro-o-anisic acid
Chemical Abstracts name 3,6-dichloro-2-methoxybenzoic acid
CAS RN [1918-00-9]; 5-hydroxy derivative [7600-50-2] EEC no. 217-635-6 Development codes Velsicol 58-CS-11; SAN 837 H (Sandoz)

dicamba-dimethylammonium
CAS RN [2300-66-5] EEC no. 218-951-7

dicamba-potassium
CAS RN [10007-85-9] EEC no. 233-002-7

dicamba-sodium
CAS RN [1982-69-0]

PHYSICAL CHEMISTRY
dicamba
Composition Tech. grade purity is 85% w/w, remainder being mainly 3,5-dichloro-o-anisic acid. Mol. wt. 221.0 M.f. C8H6Cl2O3 Form Colourless crystals; (tech. is a buff crystalline solid). M.p. 114-116 ºC B.p. >200 ºC V.p. 1.67 mPa (25 ºC, calc.) KOW logP = -0.55 (pH 5.0), -1.88 (pH 6.8), -1.9 (pH 8.9) (OECD 105) Henry 6.1  10-5 Pa m3 mol-1 S.g./density 1.488 (25 ºC) Solubility In water 6.1 g/l (25 ºC). In ethanol 922, cyclohexanone 916, acetone 810, dichloromethane 260, dioxane 1180, toluene 130, xylene 78 (all in g/l, 25 ºC). Stability Resistant to oxidation and hydrolysis under normal conditions. Stable in acids and alkalis. Decomposes at c. 200 ºC. pKa 1.97

dicamba-dimethylammonium
Mol. wt. 266.1 M.f. C10H13Cl2NO3

dicamba-diolamine
Mol. wt. 326.2 M.f. C12H17Cl2NO5

dicamba-potassium
Mol. wt. 259.1 M.f. C8H5Cl2KO3

dicamba-sodium
Mol. wt. 243.0 M.f. C8H5Cl2NaO3

COMMERCIALISATION
History Herbicide reported by R. A. Darrow & R. H. Haas (Proc. South. Weed Conf., 14th, 1961, p. 202). Introduced by Velsicol Chemical Corp., later manufactured and marketed by Sandoz AG (now Syngenta AG). Now marketed in USA and Canada by BASF, and elsewhere by Syngenta. Patents US 3013054 Manufacturers BASF; Gharda; Sannong

APPLICATIONS
Biochemistry Synthetic auxin (acting like indolylacetic acid). Mode of action Selective systemic herbicide, absorbed by the leaves and roots, with ready translocation throughout the plant via both the symplastic and apoplastic systems. Acts as an auxin-like growth regulator. Uses Control of annual and perennial broad-leaved weeds and brush species in cereals, maize, sorghum, sugar cane, asparagus, perennial seed grasses, turf, pastures, rangeland, and non-crop land. Used in combinations with many other herbicides. Dosage varies with specific use and ranges from 0.1 to 0.4 kg/ha for crop use, higher rates in pasture. Phytotoxicity Most legumes are sensitive. Formulation types GR; SL. Compatibility Precipitation of the free acid from water may occur if the dimethylammonium salt is combined with lime sulfur, heavy-metal salts, or strongly acidic materials.

dicamba
Selected products: 'Camba' (Agrimix); 'Diptyl' (Agriphar); mixtures: 'Hyprone-P' (+ MCPA+ mecoprop-P) (as mixed sodium and potassium salts) (Agrichem Int.)

dicamba-dimethylammonium
Selected products: 'Banvel' (Syngenta, BASF); 'Sivel' (Siapa)

dicamba-potassium
Selected products: mixtures: 'Marksman' (+ atrazine) (Syngenta, BASF)

dicamba-sodium
Selected products: 'Banvel SGF' (Syngenta, BASF); mixtures: 'Distinct' (+ diflufenzopyr) (diflufenzopyr also as sodium salt) (BASF); 'Lintur' (+ triasulfuron) (Syngenta); 'Overdrive' (+ diflufenzopyr) (diflufenzopyr also as sodium salt) (BASF)