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

Butachlor 60% EC (Emulsifiable Concentrate) is a selective pre-emergence herbicide from the chloroacetanilide family, specifically developed for annual grass and sedge control in paddy and upland rice. As a very long-chain fatty acid (VLCFA) synthesis inhibitor, it disrupts cell membrane formation in germinating weeds, leading to growth arrest. The 60% EC formulation (600 g/L butachlor) offers high solubility and ease of application, making it a cornerstone in global rice weed management.

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

Soil & Root Uptake: Absorbed by germinating weed roots and young shoots in flooded or moist soils.
Biochemical Blockade: Inhibits acetyl-CoA carboxylase, preventing elongation of fatty acid chains.
Growth Arrest: Disrupts meristematic tissue development in coleoptiles (grasses) and hypocotyls (sedges).
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

Rice Type	Target Weeds	Dosage (L/ha)	Application Timing
Paddy Rice	Barnyardgrass, crabgrass	2.0–3.0	Pre-emergence (0–3 days after sowing)
Upland Rice	Green foxtail, flatsedge	2.5–3.5	Pre-emergence (before weed germination)
Direct-Seeded Rice	Junglerice, sprangletop	1.5–2.5	Pre-emergence (within 7 days of planting)

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

Rice-Specific Selectivity: Safe for rice due to metabolic detoxification (glucoside conjugation).
Residual Activity: 3–4 weeks of soil protection, reducing post-emergence herbicide needs.
Cost-Effective: Low application rates (1.5–3.5 L/ha) compared to post-emergence options.
Flooded System Compatibility: Stable in waterlogged soils, ideal for paddy rice.
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

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

Contact us for bulk orders or technical support. Optimize your rice weed management with Butachlor 60% EC—proven efficacy for flooded and upland rice systems.