111991-09-4 Herbicide Weed Killer For Lawns Nicosulfuron 4% SC
Sulfonylurea herbicide Nicosulfuron 4% SC
Formulation types: 98%TC,75%WDG,75%WP,4%SC
Biochemistry:Branched chain amino acid synthesis (ALS or AHAS)
inhibitor. Acts by inhibiting biosynthesis of the essential amino
acids valine and isoieucine, hence stopping cell division and plant
growth. Maize selectivity derives from selective metabolism (P450
mediated pyrimidine-5-hydroxylation, followed by conjugation with
Mode of action:Selective systemic herbicide, absorbed by the
foliage and roots, with rapid translocation in xylem and phloem to
the meristematic tissues.
Uses:Selective post-emergence control in maize of annual grass
weeds including Setaria, Echinochtoa, Digitaria, Panicum, Lolium,
and Avena spp., broad-leaved weeds including Amaranthus spp. and
Cruciferae, and perennials such as Sorghum halepense and Agropyron
repens. Applied at 35-70 g/ha.
Oral:Acute oral LD50 for male and female rats and mice >5000 mg/kg.
Skin and eye:Acute percutaneous LD50 for male and female rats >2000 mg/kg. Moderate eye irritant;
not a skin irritant (rabbits); not a skin sensitiser (guinea pigs).
The 75% formulation is not an eye irritant.
Inhalation:LC50 for rats (4 h) 5.47 mg/l.
Noel:In 28 d feeding trials on rats and mice, no adverse effect up
to 30 g/kg diet.
/Other Non-mutagenic in the Ames test.
Toxicity:WHO (a.i.) III (Table 5); EPA (formulation) IV
Birds:Dietary oral LD50 for bobwhite quail >2250 mg/kg.
Dietary LC50 for mallard ducks and bobwhite quail >5620 ppm.
Fish:LC50 (96 h) for bluegill sunfish and rainbow trout >1000 mg/l.
Daphnia:LC50 (48 h) >1000 mg/l.
Algae:NOEC (96 h) for green algae 100 mg/l.
Worms:LC50 (14 d) for earthworms >1000 mg/kg.
Bees: LD50 (contact) >20 μg/bee; dietary LC50 (48 h) >1000 ppm. NOEC 500 ppm.
Plant:Degraded rapidly in maize, DT50 1.5-4.5 d. Residues <0.02 ppm in all crops. Hydrolysis of the
sulfonylurea bridge to form the pyridine sulfonamide and pyrimidine
amine, and hydroxylation on the pyrimidim ring, were the main
Animals:the goat, following a dose of 60 ppm, <0.1 ppm was fount
in tissues and milk; therefore nicosulfuron and its metabotites do
not bioaccumulate. Hydrolysis of the sulfonylurea bridge and
hydroxylation were the main metabolic pathways.
Soil DT50 (aerobic) 26 d (pH 6.1, 5.1% o.m., 25°C). In four sandy loams, Kd (25°C) 0.16 (pH 6.6, 1.1% o.m.) to q.73 (pH 5.4, 4.3% o.m.)
Photoiysis DT50 (soil) 60-67 d; (water) 14-19 d (pH 5), 200-250 d (pH 7), 180-200
d (pH 9). Values from separate studies were: Soil DT50 24-43 d (20~C); DT50 80-143 d (20°C). Kd 0.05-0.7. In water, DT50 15 d (pH 5, 20°C).