Chlorsulfuron
Chlorsulfuron: The Ultimate Herbicide for Effective Weed Control
Chlorsulfuron is a highly effective sulfonylurea herbicide widely used in agricultural applications. It provides excellent control of broadleaf weeds and some annual grasses while being safe for most cereal crops.
Key Features of Chlorsulfuron
- Systemic action that moves throughout the plant
- Low use rates (typically 10-40 g ai/ha)
- Long residual activity
- Excellent crop safety in registered crops
- Effective against resistant weed biotypes
Technical Specifications
| Parameter | Value |
|---|---|
| Chemical Name | 1-(2-Chlorophenylsulfonyl)-3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)urea |
| Molecular Formula | C12H12ClN5O4S |
| Molecular Weight | 357.77 g/mol |
| CAS Number | 64902-72-3 |
| Formulation Types | 75% WG, 50% WP, 25% DF |
| Solubility in Water | 3000 mg/L (pH 5), 279,000 mg/L (pH 7) |
Chlorsulfuron Application Guide
| Crop | Weeds Controlled | Application Rate | Timing |
|---|---|---|---|
| Wheat | Mustards, chickweed, prickly lettuce | 15-30 g ai/ha | Pre-emergence or early post-emergence |
| Barley | Wild buckwheat, kochia, lamb's quarters | 10-25 g ai/ha | Post-emergence |
| Oats | Smartweed, wild radish, shepherd's purse | 10-20 g ai/ha | Post-emergence |
Chlorsulfuron FAQ
Question: What is the mechanism of action of Chlorsulfuron?
Answer: Chlorsulfuron inhibits the enzyme acetolactate synthase (ALS), which is essential for branched-chain amino acid synthesis in plants. This inhibition stops cell division and leads to plant death within 1-3 weeks of application.
Question: How long does Chlorsulfuron remain active in soil?
Answer: Chlorsulfuron has a typical soil half-life of 4-6 weeks, but this can vary from 1-12 weeks depending on soil pH, moisture, and microbial activity. In high pH soils (>7.5), residues may persist longer and affect sensitive rotational crops.
Question: What safety precautions should be taken when handling Chlorsulfuron?
Answer: Always wear protective clothing, chemical-resistant gloves, and eye protection when handling Chlorsulfuron. Avoid inhalation of dust and prevent contamination of water sources. Wash thoroughly after handling and before eating, drinking, or using tobacco products.
Benefits of Using Chlorsulfuron
- Provides season-long weed control with single application
- Highly cost-effective due to low application rates
- Excellent tank-mix compatibility with other herbicides
- Flexible application timing (pre- and post-emergence)
- Reduces tillage requirements and soil erosion
Crop Rotation Restrictions
Following Chlorsulfuron application, observe these minimum rotation intervals:
- Canola: 10 months
- Sugar beets: 22 months
- Potatoes: 24 months
- Sunflowers: 11 months
- Lentils: 24 months
Chlorsulfuron Environmental Considerations
Chlorsulfuron is classified as slightly toxic to birds and mammals, but highly toxic to aquatic plants. Avoid application near water bodies and maintain buffer zones according to local regulations. The herbicide breaks down primarily through microbial degradation and hydrolysis.
Storage and Handling
- Store in original container in a cool, dry place
- Keep away from food, feed, and drinking water
- Do not store near heat or open flame
- Store above 0°C (32°F) to prevent freezing
- Keep container tightly closed when not in use
Chlorsulfuron FAQ Continued
Question: Can Chlorsulfuron be used in organic farming?
Answer: No, Chlorsulfuron is a synthetic herbicide and is not approved for use in organic farming systems. Organic producers should use mechanical weed control methods or approved organic herbicides.
Question: What is the best application method for Chlorsulfuron?
Answer: Chlorsulfuron is most effective when applied as a broadcast spray using equipment that provides uniform coverage. Use flat-fan nozzles and maintain proper boom height. Spray volume should be 80-200 L/ha depending on weed size and density.
Question: How does soil pH affect Chlorsulfuron performance?
Answer: Soil pH significantly impacts Chlorsulfuron's persistence. In acidic soils (pH <6), degradation is faster (half-life 3-4 weeks). In alkaline soils (pH >7.5), it may persist 8-12 weeks or more, potentially affecting sensitive rotational crops.
Troubleshooting Guide
| Problem | Possible Cause | Solution |
|---|---|---|
| Poor weed control | Weed resistance, improper timing, drought stress | Use recommended rate at proper growth stage, ensure adequate soil moisture |
| Crop injury | Over-application, sensitive varieties, cold stress | Follow label rates, avoid stressed crops, consider variety tolerance |
| Short residual activity | High rainfall, low pH soils | May require sequential applications in high rainfall areas |
Regulatory Status
Chlorsulfuron is registered for use in over 50 countries worldwide. Always check local regulations before use as approval status and use restrictions vary by country. In the United States, it is classified as a Restricted Use Pesticide (RUP) in some formulations.