Glean® Herbicide (Chlorsulfuron) by FMC: Technical Guide & Usage
A definitive guide to FMC Corporation's Glean®, the industry-standard sulfonylurea herbicide for broadleaf weed control in cereal crops.
Originally discovered by DuPont and now a cornerstone of the FMC Agricultural Solutions portfolio, Glean® (active ingredient: Chlorsulfuron) offers powerful, low-dose weed control. This guide covers technical specifications, dosage rates, and the critical distinction between this agricultural product and the "Glean AI" technology platform.
Best for: Wheat, Barley, Oats, and Fallow systems requiring long-term residual weed suppression.
Why Choose This Product? Key Benefits
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High Efficiency Low-Dose Chemistry: Revolutionary sulfonylurea technology allows for effective weed control at just grams per hectare (e.g., 20g/ha) rather than kilograms.
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Extended Residual Control: Provides long-lasting soil activity that suppresses weed emergence for months, keeping fields clean between rotations.
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Application Flexibility: Versatile timing allows for use both Pre-emergence (before weeds appear) and Post-emergence (from 2-leaf up to boot stage).
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Systemic Action: Absorbed through both roots and foliage, translocating rapidly to stop weed growth within hours of application.
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Broad Spectrum Performance: Specifically targets difficult broadleaf weeds like Wild Mustard, Pigweed, and Thistles while being safe for cereal crops.
Technical Specifications (Table 1)
| Parameter | Details |
|---|---|
| Brand Name | Glean® (Various formulations: 750 WDG, XP) |
| Technical Name | Chlorsulfuron |
| IRAC/HRAC Code | Group 2 (formerly Group B) - ALS Inhibitor |
| Chemical Group | Sulfonylurea |
| Solubility | pH Dependent: Low at pH 5 (~300 mg/L), High at pH 7 (~27,900 mg/L) |
| Manufacturer | FMC Corporation (Acquired from DuPont, 2017) |
How It Works: Mode of Action
Glean functions as a potent ALS (Acetolactate Synthase) Inhibitor.
- Uptake: The herbicide is rapidly absorbed by the roots and foliage of the weed.
- Translocation: It moves systematically to the meristematic tissues (growing points) of the plant.
- Inhibition: It blocks the ALS enzyme, preventing the biosynthesis of essential amino acids (valine, leucine, isoleucine). This halts cell division immediately.
Result: Susceptible weeds stop growing within hours. Visual symptoms like yellowing (chlorosis) appear in 1-3 weeks, followed by necrosis and death.
Target Crops & Pests (Table 3 Data)
| Crop / System | Target Weed Spectrum |
|---|---|
| Wheat & Barley | High Control: Wild Mustard, Blue Mustard, Redroot Pigweed, Shepherd's Purse. |
| Oats & Fallow | Variable/Time Dependent: Canada Thistle (Rosette stage), Nodding Thistle. |
| Pre-Emergence Use | Suppression Only: Annual Bluegrass, Green Foxtail, Cheatgrass. (Note: Wild Oats are generally tolerant). |
Dosage & Application Guide
The Golden Rule: Always follow the "Dose per Acre" exactly as per your local label. Rates are extremely low due to high potency.
Global Use Rates & Restrictions (Table 2 Data)
| Region / Product | Standard Rate | Application Note | Key Restriction |
|---|---|---|---|
| New Zealand (Glean 750 WDG) | 20 g / ha | Use Non-Ionic Surfactant for POST | Do not use on soils pH > 7.9 |
| USA / Plains (Glean XP) | ~0.33 oz / acre (23 g/ha) | Pre or Post-emergence | Once every 36 months (West of Hwy 183) |
| Resistance Testing (Lab) | 15 g ai / ha | Used to screen for ALS resistance | N/A |
*PHI and detailed water volumes vary by local label. Always consult the official product booklet for rotational intervals.
How to Apply: Best Practices
- Timing: Apply when weeds are small and actively growing. For thistles, apply at the rosette stage (10-15 cm) for best translocation.
- Mixing: Always add a Non-Ionic Surfactant (NIS) at 0.125% - 0.5% v/v for post-emergence sprays to help penetrate waxy leaves.
- Tank Mixing: Compatible with MCPA, 2,4-D, and Bromoxynil to manage resistance. Warning: Do not mix with organophosphates under crop stress conditions.
- Safety: Always wear PPE (gloves, mask, goggles). Wash hands thoroughly after use.
Frequently Asked Questions
1. Is "Glean" the same as "Glean AI"?
No. Glean® (FMC) is an agricultural herbicide for crops. Glean AI is a separate enterprise software company for search and knowledge management. They are unrelated entities.
2. How long does Glean stay in the soil?
It depends heavily on Soil pH. In acidic soils (pH < 6), it breaks down quickly. In high pH soils (>7.9), it can persist for 2-3 years, potentially damaging sensitive follow-crops like lentils or canola.
3. What is the active ingredient?
The active ingredient is Chlorsulfuron. It belongs to the sulfonylurea chemical family.
4. Can I use it on lawns?
Glean allows for some turf uses (like industrial sites), but it controls specific grasses. Using it on residential lawns without consulting a specific turf label can kill desired grass varieties.
5. How do I manage resistance?
Do not rely solely on Glean year after year. Rotate with herbicides from Group 4 (Auxins) or Group 6 to prevent ALS-resistant weed populations from developing.
Safety & Disclaimer
Always read and follow the instructions on the official product label. The information provided here is for guidance only. Use personal protective equipment (PPE) during application. FMC, Ally®, Express®, and Glean® are trademarks of FMC Corporation.
