Metribuzin 70% WDG Herbicide | Selective Pre- and Post-Emergent Weed Control

Metribuzin 70% WDG (Water-Dispersible Granule) is a triazinone-class selective herbicide designed for pre-emergent and post-emergent control of broadleaf weeds and annual grasses in row crops. As a photosystem II (PSII) inhibitor, it disrupts electron transport in chloroplasts, preventing weed photosynthesis and leading to chlorosis and necrosis. The 70% WDG formulation offers superior water dispersibility, reduced dust, and precise dosing, making it a staple in soybean, corn, potato, and vegetable cropping systems worldwide.

Technical Specifications

Active Ingredient: Metribuzin (CAS No. 21087-64-9)
Molecular Formula: C₈H₁₄N₄OS
Molecular Weight: 214.29 g/mol
Mode of Action: Inhibits PSII electron transport, blocking ATP and NADPH production
Formulation: 70% WDG (700 g/kg active ingredient)
Physical State: Off-white water-dispersible granules
Solubility: 1.2 g/L in water at 20°C
Soil Half-Life: 30–60 days (varies with pH and microbial activity)
Toxicity: WHO Class III (slightly hazardous); LD₅₀ > 2000 mg/kg (rat oral)

Mode of Action

Dual Uptake Pathways:
- Root Absorption: Pre-emergent application inhibits germinating seedlings.
- Foliar Uptake: Post-emergent spray is absorbed by leaves, translocating to meristematic tissues.
Photosynthetic Disruption:
- Binds to the D1 protein in PSII, blocking electron flow from water to plastoquinone.
- Disrupts carbon fixation, leading to oxidative stress and pigment degradation.
Symptom Progression:
- 3–5 days: Initial chlorosis in older leaves
- 7–10 days: Widespread necrosis and plant death

Application Guide

Crop	Target Weeds	Dosage (g/ha)	Application Timing
Soybeans	Pigweed, lambsquarters	280–560	Pre-emergent (0–3 days post-planting)
Corn (tolerant varieties)	Foxtail, crabgrass	220–500	Pre-emergent (before weed germination)
Potatoes	Nightshade, chickweed	550–1120	Pre-plant incorporated or pre-emergent
Tomatoes	Ragweed, cocklebur	200–400	Post-transplant, directed spray
Wheat	Mustard, wild oats	220–440	Early post-emergent (2–4 leaf stage)

Application Best Practices

Water Volume: 200–400 L/ha for uniform coverage
Soil Moisture: Optimal efficacy requires 10–20 mm rainfall/irrigation post-application
Tank Mixes:
- With acetochlor for enhanced grass control in corn
- With sulfentrazone for resistant broadleaves in soybeans
Adjuvants: Add non-ionic surfactant (0.25% v/v) for post-emergent applications

Key Advantages

Broad-Spectrum Efficacy: Controls 40+ weed species, including Amaranthus, Setaria, and Chenopodium.
Residual Activity: 4–6 weeks of soil protection reduces re-application needs.
Crop Selectivity: Safe for soybeans, potatoes, and tolerant corn when used at labeled rates.
Flexible Application: Suits no-till, conventional tillage, and aerial spraying systems.
Resistance Management: Compatible with Group 15 (e.g., S-metolachlor) and Group 9 (glyphosate) for rotation.

Safety & Environmental Notes

Ecotoxicity:
- Toxic to fish and algae (LC₅₀ < 1 mg/L); maintain 100 m buffer from water bodies.
- Low toxicity to birds (LD₅₀ > 1000 mg/kg).
Environmental Fate:
- Moderate soil mobility in sandy soils; potential groundwater risk.
- Degrades via microbial action and photolysis, slower in alkaline soils (pH >7).
Storage: Store at 5–30°C, protected from moisture and direct sunlight.

Packaging & Compliance

Standard Packs: 1kg, 5kg, 25kg moisture-proof bags
Custom Solutions:
- Private labeling with multilingual instructions
- OEM formulations for regional registration
Regulatory Support:
- COA, MSDS, and residue data for EU, EPA, and APAC markets
- Compliance with FAO/WHO Good Agricultural Practices

FAQ

What crops is Metribuzin 70% WDG registered for?
Registered for soybeans, corn (tolerant varieties), potatoes, tomatoes, wheat, alfalfa, and sugarcane. Always consult local labels for crop-specific approvals.

Can Metribuzin control grassy weeds?
Yes, effective against annual grasses like foxtail, crabgrass, and barnyardgrass, though control may vary vs. broadleaf weeds.

How does soil type affect Metribuzin efficacy?

High OM soils ( >3%) require higher rates (560 g/ha)
Sandy soils risk leaching; use lower rates (280 g/ha) and avoid pre-rain application

Is Metribuzin safe for post-emergent use on soybeans?
Yes, but apply before the 3-trifoliate stage; avoid during drought stress to prevent crop chlorosis.

What is the pre-harvest interval (PHI)?
PHI ranges from 21 days (soybeans) to 90 days (potatoes); check regional regulations for specifics.

Can Metribuzin be tank-mixed with herbicides like glyphosate?
Yes, compatible with glyphosate, atrazine, and acetochlor. Jar-test first and follow label rates.

How to mitigate crop injury risks?

Avoid application under stress (drought, flooding)
Test on a small plot before full-scale use in sensitive crops like corn

What is the shelf life of Metribuzin 70% WDG?
2 years when stored in original containers at cool, dry conditions.

Tank Mix Combinations

Crop	Partner Herbicide	Target Weeds	Synergistic Benefit
Soybeans	Sulfentrazone	Waterhemp, lamb’s-quarters	Enhanced broadleaf control
Corn	Atrazine	Annual grasses, broadleaves	Extended residual in corn production
Potatoes	Flumioxazin	Early-season broadleaves	Long-term soil residual
No-till Systems	Glyphosate	Emerged weeds	Burndown + soil residual combo

Resistance Management

FRAC Group: 5 (PSII inhibitors)
Rotation Strategies:
- Alternate with Group 15 (S-metolachlor) or Group 2 (chlorimuron-ethyl)
- Avoid consecutive applications; limit to 2–3 times per season
Resistance Warning:
- Reported in Amaranthus palmeri and Chenopodium album in continuous soybean systems

Real-World Applications

Midwestern Soybeans: 420 g/ha Metribuzin + 1.5 L/ha acetochlor controlled 90% of annual weeds in no-till systems.
Potato Farms in Idaho: 840 g/ha pre-emergent reduced weed competition, increasing yield by 18%.
Corn in Argentina: 350 g/ha + 2.0 L/ha atrazine provided season-long control of Setaria viridis.

Environmental Stewardship

Reduced Spray Passes: Residual activity minimizes tractor traffic and fuel use.
Bee Safety: Apply before crop flowering; avoid drift to blooming plants.
Soil Health: Compatible with conservation tillage practices.

Contact us for technical data sheets, custom formulation quotes, or regional application support – tailored solutions for global agricultural markets.