Pyrazosulfuron-ethyl
What is Pyrazosulfuron-ethyl?
Pyrazosulfuron-ethyl is a highly effective sulfonylurea herbicide widely used in rice cultivation. This selective herbicide controls a broad spectrum of annual and perennial weeds while being safe for rice crops when applied correctly.
Key Features and Benefits
- Excellent control against sedges, broadleaf weeds and some grasses
- Systemic action with both pre and post-emergence activity
- Long-lasting residual effect reduces need for multiple applications
- Highly compatible with other herbicides in tank mixtures
- Low use rate provides cost-effective weed control
Technical Specifications
| Parameter | Specification |
|---|---|
| Chemical Name | Ethyl 5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyrazole-4-carboxylate |
| Molecular Formula | C14H18N6O7S |
| Molecular Weight | 414.39 g/mol |
| Appearance | White to off-white crystalline powder |
| Melting Point | 181-182°C |
| Solubility | 14.5 mg/L in water at 25°C |
Application Guidelines
- Recommended crops: Rice (paddy fields)
- Application timing: Pre-emergence to early post-emergence (2-4 leaf stage of weeds)
- Application rate: 15-30 g a.i./ha depending on weed pressure
- Water management: Maintain 3-5 cm water level for 5-7 days after application
FAQ Section 1: Pyrazosulfuron-ethyl Basics
Q: What types of weeds does Pyrazosulfuron-ethyl control?
A: Pyrazosulfuron-ethyl effectively controls sedges (Cyperus spp.), broadleaf weeds (Ludwigia, Monochoria), and some annual grasses appearing in rice fields.
Q: How does Pyrazosulfuron-ethyl work as a herbicide?
A: Pyrazosulfuron-ethyl inhibits acetolactate synthase (ALS), a key enzyme in branched-chain amino acid biosynthesis. This stops cell division and growth in susceptible weeds.
Formulation Types
| Formulation | Concentration | Pack Size |
|---|---|---|
| Wettable Powder (WP) | 10% | 100g, 500g, 1kg |
| Water Dispersible Granules (WG) | 25% | 50g, 250g, 500g |
| Suspension Concentrate (SC) | 50g/L | 100mL, 500mL, 1L |
Mixing and Application Tips
- Always use clean water for mixing solutions
- Maintain proper water levels in rice fields during application
- Avoid application under high-temperature conditions (>35°C)
- Do not apply when rice plants are under stress
- Use recommended adjuvants for better efficacy in hard water conditions
Environmental and Safety Information
| Parameter | Value |
|---|---|
| LD50 (Oral, rat) | >5000 mg/kg (Practically non-toxic) |
| DT50 in soil | 10-30 days depending on conditions |
| PHI (Pre-harvest interval) | 40 days |
| REI (Re-entry interval) | 12 hours |
FAQ Section 2: Pyrazosulfuron-ethyl Application
Q: What is the best application method for Pyrazosulfuron-ethyl?
A: Pyrazosulfuron-ethyl should be applied as a broadcast spray over flooded paddy fields. Uniform application is critical - use proper nozzles and maintain appropriate water levels (3-5 cm) for 5-7 days post-application.
Q: Can Pyrazosulfuron-ethyl be mixed with other herbicides?
A: Yes, Pyrazosulfuron-ethyl shows good compatibility with most commonly used rice herbicides like pretilachlor, butachlor, and bensulfuron-methyl. However, always conduct a jar test before tank mixing.
Storage and Handling
- Store in original containers in a cool, dry place
- Keep away from food, feed and beverages
- Optimal storage temperature: 5-35°C
- Shelf life: 2 years from production date when stored properly
- Dispose of empty containers according to local regulations
Compatibility with Rice Varieties
| Rice Type | Tolerance Level | Notes |
|---|---|---|
| Japonica varieties | Excellent | Most tolerant rice type |
| Indica varieties | Good | Slight yellowing may occur under stress conditions |
| Hybrid varieties | Moderate | Check varietal sensitivity before application |
FAQ Section 3: Pyrazosulfuron-ethyl Safety
Q: What personal protective equipment is needed when handling Pyrazosulfuron-ethyl?
A: Basic PPE including chemical-resistant gloves, protective eyewear, long-sleeved shirt and pants, and waterproof boots should be worn during mixing and application. Respiratory protection is recommended when handling dust formulations in confined spaces.
Q: What should I do if Pyrazosulfuron-ethyl accidentally contacts skin or eyes?
A: Immediately flush eyes with clean water for at least 15 minutes. Wash affected skin areas thoroughly with soap and water. Remove contaminated clothing. If irritation persists, seek medical attention and show the product label to healthcare professionals.