Fomesafen Herbicide | Selective Weed Control for Legume Crops

Fomesafen, a selective systemic herbicide from the diphenylether family, is engineered for post-emergence control of broadleaf weeds in soybeans, peanuts, and cotton. As a protoporphyrinogen oxidase (PPO) inhibitor, it disrupts photosynthesis and membrane integrity in target plants, delivering rapid necrosis and long-lasting residual activity. Its single formulation (25% SL) simplifies application while maintaining versatility across diverse cropping systems.

Technical Specifications

Active Ingredient: Fomesafen (CAS No. 72178-02-0)
Molecular Formula: C₁₅H₁₀ClF₃N₂O₆S
Mode of Action: Inhibits protoporphyrinogen oxidase (PPO), blocking chlorophyll synthesis and causing oxidative membrane damage.
Formulation: 25% SL (Soluble Liquid)
Target Crops: Soybeans, peanuts, cotton.
Target Weeds:
- Annual Broadleaf: Pigweed, lambsquarters, morningglory, velvetleaf, ragweed.
- Perennial Broadleaf: Bindweed, Canada thistle (suppression).
- Partial Grass Control: Crabgrass (at higher rates).

Mode of Action

Foliar & Root Uptake: Absorbed by leaves and roots, translocating to meristems.
PPO Inhibition: Blocks protoporphyrinogen oxidase, halting chlorophyll production.
Oxidative Stress: Generates reactive oxygen species (ROS), causing membrane lipid peroxidation.
Symptom Timeline:
- 4–6 hours: Light-dependent leaf bleaching.
- 1–2 days: Necrotic lesions at leaf margins.
- 7–10 days: Complete plant death.

Application Guide

Crop	Target Weeds	Dosage (L/ha)	Application Timing
Soybeans	Pigweed, lambsquarters	0.68–1.36	Post-emergence (1–3 trifoliate stage)
Peanuts	Morningglory, spurge	0.82–1.36	Post-emergence (2–4 true leaves)
Cotton	Velvetleaf, smartweed	0.54–0.82	Post-emergence (cotyledon to 1st true leaf)

Application Tips:

Water Volume: Use 200–400 L/ha for uniform coverage.
Adjuvants: Add non-ionic surfactant (0.25% v/v) for enhanced uptake.
Rainfastness: 4–6 hours post-application.
Temperature: Avoid spraying above 28°C to minimize crop stress.

Key Advantages

Single Formulation: 25% SL simplifies mixing and application.
Dual Action: Foliar knockdown plus 3–4 weeks of soil residual control.
Resistance Management: Ideal tank mix partner for glyphosate or ALS inhibitors (e.g., chlorimuron-ethyl).
Crop Safety: Minimal risk of injury to soybeans and peanuts at labeled rates.
Broad Spectrum: Controls 20+ broadleaf weeds, including glyphosate-resistant biotypes.

Safety & Environmental Notes

Toxicity: Low acute toxicity (LD₅₀ >5000 mg/kg); toxic to aquatic organisms.
Environmental Impact:
- Soil half-life: 14–30 days (pH-dependent).
- Avoid runoff into water bodies.
Storage: Store at 5–35°C; protect from freezing.

Resistance Management

HRAC Group: 14 (PPO inhibitors).
Strategies:
- Rotate with Group 2 (ALS inhibitors) or Group 15 (VLCFA inhibitors).
- Tank mix with residual herbicides (e.g., S-metolachlor).

FAQ

Can Fomesafen be used pre-emergence?
No; it requires foliar absorption for activity.
How does it affect rotational crops?
Wheat, corn, and sorghum are tolerant; sensitive crops (e.g., vegetables) may require 12+ months.
Is Fomesafen effective against Palmer amaranth?
Yes, but tank mix with glyphosate for resistance management.
Can it be applied through chemigation?
No; approved only for ground or aerial foliar application.
What is the pre-harvest interval (PHI)?
45 days for soybeans, 60 days for peanuts, 70 days for cotton.

Packaging & OEM Services

Standard Packaging:
- 1L, 5L, 10L HDPE containers (25% SL).
Custom Solutions:
- Private labeling with multilingual artwork.
- Regulatory support for global markets.
- Custom tank mix recommendations.

Why Choose Fomesafen 25% SL?

Simplicity: Single formulation for easy handling.
Efficiency: Low dosage (0.54–1.36 L/ha) reduces application costs.
Sustainability: Minimizes soil persistence compared to longer-residual herbicides.

Contact us for bulk orders, technical data sheets, or custom application guidelines. Elevate your legume weed management with Fomesafen 25% SL—precision herbicide technology for modern agriculture.

Tank Mixtures and Rotational Crop Restrictions for Fomesafen

1. Tank Mix Compatibility

Fomesafen (25% SL) is highly versatile in tank mixtures, but compatibility depends on target weeds, crop stage, and regional regulations. Here’s a breakdown:

Recommended Tank Mixes

Partner Herbicide	Target Weeds	Crop	Benefits	Example Rates
Glyphosate	Broadleaf + grasses	Soybeans, cotton	Resistance management	Fomesafen 0.68–1.36 L/ha + glyphosate 1.0–1.5 L/ha
S-metolachlor	Pre-emergence residual	Soybeans	Extended soil activity	Fomesafen 0.68 L/ha + S-metolachlor 1.0–1.5 L/ha
Acifluorfen	Tough broadleaf weeds	Soybeans	Synergistic knockdown	Fomesafen 0.54 L/ha + acifluorfen 0.75–1.0 L/ha
Clethodim	Annual/perennial grasses	Soybeans, peanuts	Dual-spectrum control	Fomesafen 0.82 L/ha + clethodim 0.2–0.3 L/ha
Chlorimuron-ethyl	Broadleaf weeds in soybeans	Soybeans	Enhanced residual	Fomesafen 0.68 L/ha + chlorimuron-ethyl 10–15 g a.i./ha

Avoid These Combinations

Organophosphate Insecticides (e.g., chlorpyrifos, malathion): Risk of phytotoxicity (leaf burn) in soybeans.
Coarse Spray Nozzles: Reduces coverage; use fine-medium droplets (200–300 μm) for PPO herbicides.
High pH Water: Fomesafen efficacy drops in alkaline conditions (pH >7.5). Add a buffering agent if needed.

2. Rotational Crop Restrictions

Fomesafen’s soil residual varies by soil pH, temperature, and application rate. Key restrictions:

Sensitive Crops (Avoid Planting Within)

Crop	Pre-Harvest Interval (PHI)	Restriction After Last Application
Cereals (wheat, barley)	45–60 days	4 months (low rate) to 10 months (high rate)
Vegetables (tomatoes, lettuce)	90–120 days	12–18 months
Brassicas (canola, cabbage)	90 days	12 months
Corn	45 days	4 months (low rate) to 8 months (high rate)
Sugar Beets	90 days	18 months

Tolerant Crops

Soybeans, Peanuts, Cotton: Can be replanted immediately after harvest.
Sunflowers: Safe after 4 months if soil pH <7.5.

3. Resistance Management

Fomesafen (Group 14) is critical for ALS-resistant weeds (e.g., Palmer amaranth), but rotate with other modes of action:

Alternate With:
- Group 2 (ALS inhibitors, e.g., chlorimuron-ethyl).
- Group 15 (VLCFA inhibitors, e.g., S-metolachlor).
- Group 4 (synthetic auxins, e.g., dicamba).
Tank Mixes: Always combine with a herbicide from a different group to delay resistance.

4. Environmental & Safety Notes

Water Contamination: Toxic to fish and algae. Avoid spraying within 100 meters of water bodies.
Drift Risk: Volatility is low, but fine droplets can drift. Use DRT nozzles and apply in calm conditions (<16 km/h wind).
pH Management: Soil residual increases in alkaline soils (pH >7.5). Test soil pH before planting rotational crops.

5. Example Rotation Plan

Year 1: Soybeans with fomesafen (0.68 L/ha) + glyphosate.
Year 2: Wheat (planted 4 months after soybean harvest).
Year 3: Corn (planted 8 months after wheat harvest).

Always consult the product label for region-specific restrictions and tank mix guidelines.

What is the recommended application rate of Fomesafen for different crops?

The recommended application rates of fomesafen (25% SL) vary by crop and target weeds, with adjustments based on weed size, soil conditions, and regional guidelines. Below is a detailed breakdown:

1. Soybeans

Fomesafen is a cornerstone herbicide for broadleaf weed control in soybeans, offering both foliar and residual activity.

Target Weeds: Pigweed, lambsquarters, morningglory, velvetleaf, ragweed, and glyphosate-resistant biotypes 12.
Application Rate:
- Standard Rate: 0.68–1.36 L/ha (25% SL) applied post-emergence when soybeans have 1–3 trifoliate leaves and weeds are at the 2–4 leaf stage 12.
- Resistant Weeds: Higher rates (up to 1.36 L/ha) are recommended for tough species like Palmer amaranth 1.
Key Notes:
- Add a non-ionic surfactant (0.25% v/v) for enhanced efficacy 1.
- Avoid spraying above 28°C to minimize crop stress 1.
- Water volume: 200–400 L/ha for uniform coverage 1.

2. Peanuts

Fomesafen provides selective control of broadleaf weeds in peanuts without significant crop injury.

Target Weeds: Morningglory, spurge, pigweed, and lambsquarters 1.
Application Rate: 0.82–1.36 L/ha (25% SL) applied post-emergence at the 2–4 true leaf stage of peanuts 1.
Key Notes:
- Tank mixing with clethodim (0.2–0.3 L/ha) improves grass control 1.
- Pre-harvest interval (PHI): 60 days 1.

3. Cotton

Fomesafen is registered for early post-emergence use in cotton, targeting broadleaf weeds.

Target Weeds: Velvetleaf, smartweed, and pigweed 1.
Application Rate: 0.54–0.82 L/ha (25% SL) applied when cotton is at the cotyledon to 1st true leaf stage 1.
Key Notes:
- Avoid mixing with organophosphate insecticides to prevent phytotoxicity 1.
- PHI: 70 days 1.

4. Dry Beans & Snap Beans

Fomesafen is labeled for use in dry beans (e.g., navy beans) and snap beans, with rates adjusted for weed pressure.

Target Weeds: Common ragweed, lambsquarters, and pigweed 20.
Application Rate:
- Dry Beans: 0.36–0.72 L/ha (25% SL) applied post-emergence at the 1–2 trifoliate stage 20.
- Snap Beans: 0.36–0.72 L/ha (25% SL) applied early post-emergence (weeds ≤4 inches tall) 20.
Key Notes:
- In wet seasons, a second application may be needed to sustain control 20.
- Tank mixing with S-metolachlor (1.0–1.5 L/ha) extends residual activity 1.

5. Potatoes

Fomesafen is used in potatoes for selective broadleaf weed control, particularly yellow nutsedge suppression.

Target Weeds: Yellow nutsedge, pigweed, and nightshade 21.
Application Rate: 0.54–0.82 L/ha (25% SL) applied post-emergence when weeds are small (≤3 inches) 21.
Key Notes:
- Avoid contact with potato foliage to prevent temporary chlorosis 21.
- PHI: 45 days 1.

6. Cassava

While fomesafen is not widely registered for cassava, research indicates its potential for broadleaf weed control.

Application Rate: 0.4–0.6 L/ha (25% SL) applied post-emergence to young weeds 211.
Key Notes:
- Phytotoxicity risk is low, but avoid spraying during drought stress 11.
- Local trials are recommended to validate efficacy and crop safety 11.

7. Field Cucumbers (Minor Use)

Fomesafen is approved for banded applications in field cucumbers in specific regions.

Application Rate: 1.0 L/ha (25% SL) applied pre-emergence or pre-transplant as a banded spray 12.
Key Notes:
- PHI: 42 days 12.
- Avoid drift onto cucumber foliage to prevent injury 12.

Factors Influencing Application Rates

Weed Size & Density:
- Smaller weeds (2–4 leaf stage) require lower rates, while larger weeds may need higher doses 120.
Soil pH & Organic Matter:
- In alkaline soils (pH >7.5), fomesafen’s soil residual activity increases, potentially affecting rotational crops 13.
Adjuvants & Water Volume:
- Non-ionic surfactants enhance uptake, while higher water volumes (200–400 L/ha) improve coverage 120.
Resistance Management:
- Tank mix with glyphosate or ALS inhibitors (e.g., chlorimuron-ethyl) to delay resistance development 120.

Rotational Crop Restrictions

Fomesafen’s soil persistence (14–30 days) varies by pH and rate, impacting rotational crops:

Sensitive Crops: Wheat, corn, and vegetables require 4–18 months before replanting, depending on rate 12.
Tolerant Crops: Soybeans, peanuts, and cotton can be replanted immediately after harvest 1.

Safety & Environmental Considerations

Toxicity: Low mammalian toxicity (LD₅₀ >5000 mg/kg) but highly toxic to aquatic organisms 1.
Drift Management: Use low-drift nozzles and avoid spraying near water bodies 112.
Label Compliance: Always follow regional label instructions for rates, timing, and rotational intervals