metsulfuron-mythyl 10% 60% WP WDG 97% TC super herbicide

metsulfuron-mythyl 10% 60% WP WDG 97% TC super herbicide

NOMENCLATURE

metsulfuron-methyl

Common name metsulfuron-methyl

IUPAC name methyl 2-(4-methoxy-6-methyl-1,3,5-triazin-2-ylcarbamoylsulfamoyl)benzoate  

Chemical Abstracts name methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoate  

CAS RN [74223-64-6]  Development codes DPX-T6376 (); IN-T6376  

metsulfuron

Common name metsulfuron (BSI, WSSA, ANSI, draft E-ISO, (m) draft F-ISO)

IUPAC name 2-(4-methoxy-6-methyl-1,3,5-triazin-2-ylcarbamoylsulfamoyl)benzoic acid  

Chemical Abstracts name 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]amino]sulfonyl]benzoic acid  

CAS RN [79510-48-8]  

COMMERCIALISATION

History Herbicidal properties of metsulfuron-methyl reported by R. I. Doig et al. (Proc. Int. Congr. Plant Prot., 10th, 1983, 1, 324). Introduced by E. I. du Pont de Nemours and Co.; first approval in 1984.  Patents US 4370480

APPLICATIONS

metsulfuron-methyl

Biochemistry Affects sensitive weeds through inhibition of the enzyme acetolactate synthase (ALS). Inhibition of ALS leads to the rapid cessation of cell division and subsequent growth processes in plants.  Mode of action Selective systemic herbicide absorbed through the roots and foliage and translocated to the apex of the plants. Symptoms appear within days with death within 2-4 weeks.  Uses Controls a wide range of grass and broad-leaved weeds in wheat, barley, rice, oats and triticale by post-emergence application, at 4-8 g/ha. Formulation types WG.  

ANALYSIS

Product and residue analysis by hplc/ms/ms (Handbook of Residue Analytical Methods, pages 400-410; CIPAC Handbook, 1998, H, 204)  

MAMMALIAN TOXICOLOGY

metsulfuron-methyl

Oral Acute oral LD50 for male and female rats >5000 mg/kg.  Skin and eye Acute percutaneous LD50 for rabbits >2000 mg/kg. Not a skin or eye irritant (rabbits). Not a skin sensitiser (guinea pigs).  Inhalation LC50 (4 h) for male and female rats >5 mg/l air.  NOEL (18 mo) for mice 5000 ppm; (2 y) for rats 500 ppm; (1 y) for male dogs 500 ppm; (1 y) for female dogs 5000 ppm.  ADI 0.22 mg/kg  Other Not genotoxic; non-teratogenic.  Toxicity class WHO (a.i.) U; EPA (formulation) IV  EC classification N; R50, R53  

ECOTOXICOLOGY

metsulfuron-methyl

Birds Acute oral LD50 for mallard ducks >2510 mg/kg. Dietary LC50 (8 d) for mallard ducks and bobwhite quail >5620 mg/kg diet.  Fish LC50 (96 h) for rainbow trout and bluegill sunfish >150 mg/l.  Daphnia EC50 (48 h) >120 mg/l.  Algae EC50 (72 h) for green algae 0.157 mg/l.  Other aquatic spp. EC50 for Lemna gibba 0.36 mg/l.  Bees Non-toxic to bees; LD50 (oral) >44.3 mg/bee; (contact) >50 mg/bee.  Worms LC50 >1000 mg/kg.  

ENVIRONMENTAL FATE

Animals In mammals, following oral administration, metsulfuron-methyl is excreted predominantly unchanged. The methoxycarbonyl and sulfonylurea groups are only partly degraded, by O-demethylation and hydroxylation.  Plants In plants, undergoes complete degradation within a few days, by hydrolysis and conjugation. In addition to the hydroxymethyl analogue, other metabolites identified include methyl 2-(aminosulfonyl)benzoate and 2-(aminosulfonyl)benzoic acid. Rapidly metabolised within cereal plants.  Soil/Environment In soil, metsulfuron-methyl is broken down both by chemical hydrolysis and by microbial degradation. DT50 (ave.) in a range of field soils is 52 days, with faster degradation in acidic soils.