FLUMETSULAM

Common name: Flumetsulam

Chemical Name:

2′,6′-difluoro-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonanilide

N-(2,6-difluorophenyl)-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine-2-sulfonamide

Other names: Broadstrike, Python, Scorpion (Dow)

Molecular formulae:C₁₂H₉F₂N₅O₂S Chemical Structure:

Physical and Chemical Properties:

Molecular weight: 325.3; Physical form: Off-white, odourless solid. Density:1.77 (21 °C); Melting point: 251-253 °C; Flash point:>93 °C; Vapour pressure:3.7 ×10-7 mPa (25 °C); Partition coefficient(n-octanol and water): logP = -0.68 (25 °C, unstated pH); pKa:4.6; Solubility: In water 49 mg/l ( pH 2.5); solubility increases with pH. Very slightly soluble in acetone and methanol. Insoluble in hexane and xylene; Stability: Aqueous photolysis DT50 6-12 mo. Soil photolysis DT50 3 mo.

Purity: 97%

Uses: Small-grain cereals, maize, soybeans, peas, clover, medic and turf.

Mode of actions:

Flumetsulam is active following applications to soil and to foliage. It can be applied prior to planting and pre-emergence in soybeans and pre-emergence to early post-emergence (from 2-4 true leaves in weeds) in maize. Flumetsulam is safe to maize, soybeans and small-grain cereals, but phytotoxic to oilseed rape, cotton and sugar beet.

Toxicology:

Oral:Acute oral LD₅₀ for rats >5000 mg/ kg. Percutaneous: Acute percutaneous LD₅₀ for rabbits >2000 mg/kg. Slightly irritating to eyes (rabbits). Non-sensitising to skin (guinea pigs). Inhalation: LC₅₀ (4 h) >1.2 mg/l. Phytotoxicity: Crops damaged by soil application of flumetsulam include sugar beet, cotton, oilseed rape, grain sorghum, tomatoes, and sunflowers. ADI:0.17 mg/ kg.

Environmental Profile

Ecotoxicology:

Bees: LC₅₀ >100 μg/bee. NOEL 36 μg/bee. Birds: Acute oral LD₅₀ for bobwhite quail >2250 mg/l. Dietary LC₅₀ (8 d) for bobwhite quail and mallard ducks >5620 mg/l.

Daphnia: Non-toxic. Fish: LC₅₀ (96 h) for silverside minnow >379 mg/l. Non-toxic to fathead minnow and bluegill sunfish. Other aquatic spp.: LC₅₀ for shrimp >349.

Environmental fate:

Animals: Rapidly cleared via urine and faeces with no metabolites. 5-Hydroxy metabolite found in the hen. Soil: Availability of flumetsulam in soil is principally dependent upon soil pH and organic matter. Herbicidal activity increases as pH increases and organic matter decreases. DT50 in soil (25 °C, Plant: DT50 in maize 2 h, soya beans 18 h, Chenopodium 131 h. Metabolites depend on the species; 5-hydroxy or 5-methoxy derivatives are common.

Transport Information

Hazard Class: III(Slightly hazardous)

Other products:

Straight formulated products: Flumetsulam 80% WDG

Mixtures:

Thifensulfuron-methyl+bentazone+flumetsulam Florasulam+flumetsulam