Active ingredient

Cyhalofop-butyl

Chemical name

butyl (R)-2-[4-(4-cyano-2-fluorophenoxy)phenoxy]propanoate

Classification

Herbicide  / Agrochemical

Formulation

10%EC, 18%EC, 10%SC, 200g/l OD

Biochemistry

Fatty acid synthesis inhibitor, by inhibition of acetyl CoA carboxylase (ACCase). Selectivity between susceptible grasses and dicotyledonous plants is attributed to the forms of ACCase present and their compartmentalisation within plant cells. Susceptible grasses contain the susceptible eukaryotic form of ACCase; dicotyledonous plants contain both susceptible eukaryotic and herbicide-resistant prokaryotic forms of ACCase, rendering them resistant to cyhalofop-butyl. Rice tolerance to cyhalofop-butyl is due to rapid metabolism to the herbicidally inactive diacid (t1/2 <10 hr), whereas susceptible grasses metabolise cyhalofop-butyl to the herbicidally active monoacid.

 Mode of action

Post-emergence herbicide with foliar uptake only and no soil activity. A systemic herbicide that is readily absorbed by plant tissue, is moderately phloem-mobile and accumulates in meristematic regions. Grass weeds cease growth immediately after treatment, with yellow patches appearing within 2-3 days to one week, leading to necrosis and death of the whole plant within 2 to 3 weeks.

Usage

For post-emergence control of grass weeds in rice. Applied at 75-100 g/ha in tropical rice and 180-310 g/ha in temperate rice. For selectivity in Poaceae species, see M. Ito et al., J. Weed Sci. & Tech. 43(2) 122-128 (1998).

Mammalian Toxicology

Oral: Acute oral LD50 for male and female rats, and for male and female mice >5000 mg/kg. 

Skin and eye: Acute percutaneous LD50 for male and female rats >2000 mg/kg.

Inhalation: LC50 for rats >5.63 mg/l.

Cyhalofop-butyl 18%EC

Item

Appearance

A.I. Content

pH value

Water content

Density

Emulsion stability

Yellow Liquid

≥18.0%

4.0-7.0

≤0.5%

0.955

0.5h, Cream does not exceed 1ml, no Free Oil

1h, Cream does not exceed 2ml, no Free Oil

24h, re-emulsified again, can be emulsified completely

24.5h, Cream does not exceed 2ml, no Free Oil

  Item

Appearance

A.I. Content

pH value (1% aqueous solution)

Suspensibility

Gravity

  Specification

Light brown liquid

≥200g/l

4.0-7.0

≥90%

0.90-1.10 g/mL