MESOSULFURON-METHYL
 
Introduction: A systemic herbicide used for post-emergence control of grasses and other weeds in cereals including spring wheat, winter wheat, durum wheat, winter rye.
Common name: Mesosulfuron-methyl
Another name: Mesomaxx, etc.
Chemical name: methyl 2-[(4,6-dimethoxypyrimidin-2-ylcarbamoyl)sulfamoyl]-a-(methanesulfonamido)-p-toluate
Empirical formula: C17H21N5O9S2
Structural formula:
Mol. Weight: 503.51 g/mol
CAS No.: 208465-21-8
Specifications
Leading Mesosulfuron-methyl supplier
Mesosulfuron-methyl 30 g/L OF
Mesosulfuron-methyl 95% TC
Packing:
BULK PACKING
Solid: 25kg/Bag, 25kg/Drum, 50kg/Drum etc.
Liquid: 200L/Drum, 20L/Drum, 10L/Drum ect.
SMALL PACKING
Solid: 1kg/Alu bag, 500g/Alu bag, 200g/Alu bag, 100g/Alu bag, 50g/Alu bag, 15g/Alu bag etc.
Liquid: 5L/Drum, 1L/Bottle, 500ml/Bottle, 250ml/Bottle, 100ml/Bottle, 50ml/Bottle etc.
Customerized packing label
Mesosulfuron-methyl FAO standard
Professional registration
HAZARDS IDENTIFICATION
Hazard statement(s)
H400 (100%): Very toxic to aquatic life.
Precautionary statement(s)
P273: Avoid release to the environment.
P391: Collect spillage.
P501: Dispose of contents/container to ...
Supplemental Hazard Statements: none
MAMMALIAN TOXICOLOGY
Acute toxicity: 1) Acute oral LD50 for rat: >5000 a.i.mg/kg. 2) Acute dermal LD50 for rat: >5000 a.i.mg/kg. 3) Inhalation LC50 (4 h) for rat: >1.33 a.i.mg/L. 4) Non-irritating to skin (rabbits). 5) Slightly-irritating to eye (rabbits). 6) Not a skin sensitiser (guinea pigs).
Not mutagenic.
ADI: 1.0 mg/kg b.w./day [Mouse, SF=100]
Classification:
EC Risk Classification: N - Dangerous for the environment: R50/53
ECOTOXICOLOGY
Effect on birds: low toxicity to birds, acute oral LD50 for Mallard ducks is >2000 a.i.mg/kg. Effect on fish: low toxicity to fish, acute 96 hour LC50 for Rainbow trout is >100 a.i.mg/L. Effect on aquatic invertebrates: low toxicity to aquatic invertebrates, acute 48 hour EC50 for Daphnia magna is >100 a.i.mg/L. Effect on algae: moderate toxicity to algae, acute 72 hour EC50 for Raphidocelis subcapitata is 0.2 a.i.mg/L. Effect on honeybees: moderate toxicity to honeybees, contact acute 48 hour LD50 is >13 a.i.μg/bee, oral acute 48 hour LD50 is 5.6 a.i.μg/bee. Effect on earthworms: low toxicity to earthworms, acute 14 day LC50 for Eisenia foetida is >1000 a.i.mg/kg.
ENVIRONMENTAL FATE
Mesosulfuron-methyl's production may result in its release to the environment through various waste streams; its use as a herbicide will result in its direct release to the environment. If released to air, a vapor pressure of 8.25×10-14 mm Hg at 25 deg C indicates mesosulfuron-methyl will exist solely in the particulate phase in the atmosphere. Particulate-phase mesosulfuron-methyl will be removed from the atmosphere by wet or dry deposition. The compound is stable to photolysis. If released to soil, mesosulfuron-methyl is expected to have very high mobility based upon an estimated Koc of 11. The pKa of mesosulfuron-methyl is 4.35, indicating that this compound will exist almost entirely in anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 1.1×10-16 atm-cu m/mole. Biodegradation of mesosulfuron-methyl is expected in soil and water with reported aerobic products of 2-amino-4,6-dimethoxypyrimidine, 4,6-dimethoxypyrimidin-2-ylurea and mesosulfuron acid. If released into water, mesosulfuron-methyl is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Mesosulfuron-methyl will undergo hydrolysis in the environment and has reported half-lives of 3.5, 253 and 319 days at pH 4, 7 and 9, respectively, at 25 deg C.
Usage: Reported by E Hacker et al., (Proc. BCPC Conf. - Weeds, 2001, 1, 43), discovered in 1996, and under development by Aventis CropScience (now Bayer CropScience). Manufacturers: Bayer CropScience. Biochemistry: Branched chain amino acid synthesis (ALS or AHAS) inhibitor. Acts by inhibiting biosynthesis of the essential amino acids valine and isoleucine, hence stopping cell division and plant growth. Mefenpyr-diethyl enhances metabolism of the herbicide selectively in cereal crop plants.
Application: For early to mid post-emergence control of grass and some broad-leaved weeds in winter, spring and durum wheat, triticale and rye, at 15 g/ha. For use in combination with mefenpyr-diethyl at 45 g/ha.
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