Butachlor 60% EC Herbicide | Pre-Emergence Weed Control for Rice

Technical Specifications

• Active Ingredient: Butachlor (CAS No. 23184-66-9)
• Molecular Formula: C₁₆H₂₂ClNO₂
• Molecular Weight: 293.81 g/mol
• Mode of Action: Inhibits VLCFA synthesis, blocking cell membrane formation in germinating seedlings.
• Formulation: 60% EC (600 g/L Butachlor)
• Physical State: Light amber to brown oily liquid
• Solubility: 20 ppm in water at 25°C; soluble in acetone, xylene
• Vapor Pressure: 2.6×10⁻⁷ mmHg at 25°C
• pH Range: 5.0–8.0 (stable in agricultural waters)

Mode of Action

1. Soil & Root Uptake: Absorbed by germinating weed roots and young shoots in flooded or moist soils.
2. Biochemical Blockade: Inhibits acetyl-CoA carboxylase, preventing elongation of fatty acid chains.
3. Growth Arrest: Disrupts meristematic tissue development in coleoptiles (grasses) and hypocotyls (sedges).
4. Symptom Timeline:
   • 3–7 days: Stunted shoot growth, curled coleoptiles in grasses.
   • 10–14 days: Chlorosis and necrosis in emerging seedlings, failure to produce new leaves.

Application Guide

Application Tips:

• Water Management: Maintain 3–5 cm water depth for 3–5 days post-application in paddy fields.
• Mixing: Dilute in 300–500 L water/ha; add non-ionic surfactant (0.25% v/v) for uniform soil coverage.
• Soil Type Adjustments:
  • High organic matter (OM >2%): Use higher rates (2.5–3.5 L/ha).
  • Sandy soils: Lower rates (1.5–2.0 L/ha) to reduce leaching risk.
• Tank Mixes:
  • With Bentazone: Controls broadleaf weeds in upland rice.
  • With Mefenacet: Enhances sedge control in paddy systems.

Key Advantages

1. Rice-Specific Selectivity: Safe for rice due to metabolic detoxification (glucoside conjugation).
2. Residual Activity: 3–4 weeks of soil protection, reducing post-emergence herbicide needs.
3. Cost-Effective: Low application rates (1.5–3.5 L/ha) compared to post-emergence options.
4. Flooded System Compatibility: Stable in waterlogged soils, ideal for paddy rice.
5. Broad-Spectrum Grass Control: Effective against 15+ annual grass and sedge species.

Safety & Environmental Notes

• Toxicity:
  • Low acute toxicity to mammals (LD₅₀ > 2000 mg/kg for rats).
  • Highly toxic to fish and aquatic invertebrates (keep 50 m from water bodies).
• Environmental Impact:
  • Soil half-life: 10–20 days (degrades via microbial action and hydrolysis).
  • Moderate leaching potential in sandy soils; avoid use in areas with shallow groundwater.
• Storage: Store in cool, dry place; protect from direct sunlight and freezing.

Resistance Management

• HRAC Group: 15 (VLCFA synthesis inhibitors).
• Strategies:
  • Rotate with Group 2 (bensulfuron-methyl) or Group 14 (fomesafen).
  • Tank mix with herbicides of different modes of action to delay resistance.
• Current Resistance Status: Limited resistance reported, primarily in continuous rice systems.

FAQ

1. Can Butachlor 60% EC be used post-emergence?
   No; it requires uptake by germinating seedlings for efficacy.
2. What is the pre-harvest interval (PHI)?
   PHI is 30 days for rice, ensuring residue compliance with food safety standards.
3. Is Butachlor compatible with organic farming?
   No; synthetic herbicide prohibited in organic systems.
4. How does Butachlor affect rotational crops?
   Sensitive crops (e.g., vegetables, crucifers) may require 2–3 months before planting; consult label for specifics.
5. Can it be applied through irrigation systems?
   Yes, via chemigation in upland rice, but ensure uniform distribution.

Real-World Application Cases

• South Asian Paddy Fields: 2.5 L/ha Butachlor 60% EC + 0.5 L/ha bentazone controlled 90% of barnyardgrass and flatsedge in transplanted rice.
• Southeast Asian Upland Rice: 3.0 L/ha Butachlor 60% EC reduced weed competition, increasing rice yield by 20% compared to untreated plots.
• Direct-Seeded Rice in China: 2.0 L/ha Butachlor 60% EC + 1.0 L/ha mefenacet provided season-long control of junglerice and sprangletop.

Packaging & Compliance

• Standard Packaging: 5L, 10L, 20L HDPE containers.
• Regulatory Support: COA, SDS, and MRL data available for global markets (e.g., Asia, Africa, Latin America).
• Custom Solutions: Private labeling and formulation blending (e.g., butachlor + propanil premixes for dual action).