Thidiazuron

Product Details

CasNo： 51707-55-2

MF： C9H8N4OS

Appearance： crystals

Delivery Time： 15 days

Packing： 25kg/drum

Purity： 97%

1. Basic Information

• English Common Name: Thidiazuron
• Other Names: Dropp, Defoliant Urea, etc.
• Chemical Name: 1-Phenyl-3-(1,2,3-thiadiazol-5-yl)urea
• Molecular Formula: C₉H₈N₄OS
• Molecular Weight: 220.2
• CAS Registry Number: 51707-55-2

2. Physicochemical Properties

• Appearance: Colorless and odorless crystals.
• Melting Point: 210.5-212.5℃ (decomposes).
• Vapor Pressure: 3×10⁻³ mPa (at 25℃).
• Solubility (at 20℃):
  • 0.002 g/100 mL in water
  • 0.0035 g/100 mL in benzene
  • 0.8 g/100 mL in acetone
  • 21 g/100 mL in cyclohexanone
  • 50 g/100 mL in dimethylformamide (DMF)
• Stability: Molecularly stable in the pH range of 5-9; stable for more than 30 days when stored at 60℃, 90℃, and 120℃.

3. Toxicity

It is a low-toxicity plant growth regulator:

• Acute oral LD₅₀ for rats: >4000 mg/kg
• Acute dermal LD₅₀ for rats: >1000 mg/kg
• Acute inhalation LD₅₀ for rats: >2.3 mg/L
• It causes mild irritation to rabbit eyes but no irritation to the skin. It has no teratogenic, carcinogenic, or mutagenic effects.

4. Mechanism of Action

Thidiazuron can be absorbed through the stems and leaves of plants and then transported to the junction of petioles and stems:

• At higher concentrations: It stimulates ethylene production and enhances the activity of pectinase and cellulase, thereby promoting the defoliation of mature leaves and accelerating boll opening in cotton.
• At lower concentrations: It exhibits cytokinin-like activity, which can induce bud differentiation from callus in some plants.

5. Efficacy

• Primarily used as a defoliant for cotton.
• Also applicable to defoliation of apple trees, grapevines, and Hibiscus species; and growth regulation of crops such as kidney beans, soybeans, and peanuts.
• At high concentrations, it can control weeds like barnyard grass, crabgrass, and crabgrass.
• At ultra-low concentrations, it can be used as a fruit-enlarging agent.

6. Formulations

Main formulations include:

• 50% Thidiazuron Wettable Powder (WP)
• 0.2% Thidiazuron Soluble Concentrate (SC)
• 0.5% Thidiazuron Soluble Concentrate (SC)

7. Suitable Crops & Application Methods

• Cotton:
  • When 70% of cotton bolls crack (at a temperature of 14-22℃), spray the foliage with a 1000 mg/L solution to achieve defoliation and early boll opening.
  • Alternatively, use 540 g/L thidiazuron + diuron suspension concentrate: When the cotton boll opening rate reaches approximately 40%, apply 9-12 mL per mu (1 mu ≈ 0.0667 hectares) diluted in 30-50 kg of water for uniform spraying.
• Grapes:
  • During the young fruit enlargement stage after physiological fruit drop, spray with a 800-1000x dilution of 0.2% thidiazuron soluble concentrate for excellent fruit-enlarging effects.
• Cucumbers:
  • After harvest, spray the receptacles of female flowers with a 2 mg/L solution to promote fruit set and increase single fruit weight.
• Celery:
  • Spray the green leaves with a 1-10 mg/L solution to maintain their green color for an extended period.