What Is Diquat? An Overview of This Fast-Acting Contact Herbicide

Diquat is a fast-acting, non-selective contact herbicide widely used to control broadleaf weeds and aquatic vegetation by disrupting photosynthesis.

Diquat is a non-selective contact herbicide widely used for controlling unwanted vegetation in both agricultural and non-crop settings. It is especially known for its rapid action, quickly desiccating plant tissues upon contact, and is often chosen when speed of control is critical. The active ingredient, diquat dibromide, belongs to the bipyridyl class of herbicides and works by disrupting the photosynthetic process, effectively burning down green tissues in a matter of hours.

Unlike systemic herbicides such as glyphosate, which travel through the plant’s vascular system to kill from root to shoot, diquat remains on the surface tissues where it lands. This makes it ideal for pre-harvest desiccation, aquatic weed control, and non-selective burndown in industrial or roadside areas. It is commonly formulated as diquat 20% SL or diquat 150 SL, offering flexibility for different application needs.

Diquat is also favored for aquatic weed management, thanks to its strong performance against algae and submerged species like hydrilla and water hyacinth. Its broad use profile, combined with fast visual results and minimal soil persistence, makes it a popular tool in integrated vegetation management (IVM) programs across farming, landscaping, forestry, and public works.

How Diquat Works: Chemical Profile and Mode of Action

Diquat’s herbicidal power comes from its active ingredient diquat dibromide, a bipyridyl compound that acts quickly upon contact with green plant tissue. Once applied, diquat interferes with the photosynthetic electron transport system in chloroplasts. This action causes the rapid formation of reactive oxygen species, which in turn destroy cell membranes and lead to the collapse of plant cells within hours.

Because diquat is a contact herbicide, it doesn’t move through the plant’s vascular system. Instead, it only affects the parts it touches, making uniform coverage essential for effective results. This unique mechanism results in fast visual symptoms—typically wilting, browning, and desiccation—often within the same day of application.

Primary Uses of Diquat in Agriculture and Vegetation Management

Diquat is valued for its broad-spectrum utility across multiple environments where rapid burndown of green vegetation is required. In agriculture, it’s commonly used for:

• Pre-harvest desiccation in crops such as potatoes, beans, and oilseed rape to accelerate drying and ease mechanical harvesting.
• Burndown before planting to clear fields of existing weeds without soil disturbance.
• Spot treatment in perennial crops like orchards and vineyards for localized weed control.

Outside of cultivated fields, diquat also plays a key role in non-crop areas, including:

• Aquatic environments: for managing submerged and floating weeds in ponds, lakes, canals, and irrigation ditches.
• Public spaces and infrastructure: such as roadsides, railways, airport runways, and industrial zones, where quick vegetation suppression is essential for visibility and safety.

Thanks to its fast action and short soil residual, diquat is often selected when quick weed control is needed without long-term environmental persistence.

Diquat vs. Glyphosate: Key Differences and When to Use Each

While both diquat and glyphosate are non-selective herbicides, they differ significantly in how they work, how fast they act, and what they are best suited for:

Feature	Diquat	Glyphosate
Mode of Action	Contact, disrupts photosynthesis	Systemic, inhibits amino acid synthesis
Speed of Action	Rapid (visible effects in hours)	Slow (visible effects in days)
Translocation	No – remains on surface tissues	Yes – moves through entire plant
Best For	Quick desiccation, aquatic weed control	Deep-rooted perennial weed control
Residual Activity	Minimal	Moderate

When to choose diquat: when you need fast visual results, such as pre-harvest dry-down, aquatic weed suppression, or burndown in non-crop areas.
When to choose glyphosate: when you require deep systemic control, especially for perennial weeds or no-till field preparation.

How to Apply Diquat Safely and Effectively

Diquat is typically applied as a foliar spray using ground sprayers, aerial equipment, or aquatic application systems depending on the target area. Because it is a contact herbicide, effective coverage of all green tissue is critical. Uniform droplet distribution across leaf surfaces ensures maximum efficacy.

Recommended Application Tips:

• Use sufficient water volume (200–600 L/ha) for better leaf coverage.
• Apply in calm weather to reduce drift.
• Add a non-ionic surfactant to enhance adhesion and penetration.
• Avoid use on dusty or stressed plants, as effectiveness may drop.

Safety and PPE Guidelines:

• Always wear protective clothing, gloves, and goggles when mixing or applying.
• Diquat is toxic by ingestion and eye contact, so follow local safety regulations strictly.
• Observe re-entry intervals (REI) and pre-harvest intervals (PHI) as per label directions.
• Avoid contamination of water sources used for drinking or irrigation, especially in aquatic weed control programs.

When handled correctly, diquat provides highly effective weed control with manageable safety risks. Many formulations are registered with specific buffer zones and EPA or FAO guidelines for safe use.

Environmental Behavior and Rainfastness of Diquat

Diquat is known for its limited environmental mobility and low soil persistence, making it a suitable choice for use in environmentally sensitive areas. Once applied, it rapidly binds to clay particles and organic matter in the soil, rendering it biologically inactive. This means there is minimal risk of leaching into groundwater or affecting non-target crops when used correctly.

Key Environmental Traits:

• Soil residual activity: Very low – diquat does not affect subsequent crops.
• Water degradation: In aquatic systems, diquat dissipates quickly through photodegradation and adsorption.
• Impact on non-target organisms: Low toxicity to mammals and birds; however, moderate toxicity to fish and aquatic invertebrates, so care must be taken during aquatic applications.
• Rainfastness: Diquat becomes rainfast typically within 30 minutes to 1 hour after application. This ensures efficacy even under variable weather conditions.

Thanks to its fast degradation profile and low volatility, diquat is often favored in integrated vegetation programs where short-term impact with long-term safety is required.

Available Formulations and Packaging Options

Diquat is available in various commercial formulations tailored to different application needs and market preferences. The most commonly used formulation is:

• Diquat 20% SL (Soluble Liquid): Ideal for foliar sprays and aquatic applications, offering excellent miscibility and ease of handling.

Other regional formulations include diquat 15% SL, diquat dibromide 40% SL, and dual-active blends (e.g., diquat + paraquat), depending on local registration and usage patterns.

Common Packaging Configurations:

• 100mL / 250mL / 500mL: Small-scale retail or horticultural use
• 1L / 5L / 10L HDPE bottles: Agricultural and landscape operations
• 20L / 200L drums & IBC tanks: Bulk use in industrial vegetation control and aquatic weed management

OEM & Customization Support:

We offer full support for:

• Private label design with multi-language artwork
• Custom formulation adjustments to meet local regulatory or crop-specific requirements
• Flexible delivery volumes for trial batches or container load shipments

Whether you’re serving farmers, municipal contracts, or distributors, we can supply compliant, scalable, and brand-ready solutions to fit your market.

Global Market Adoption and Regulatory Notes

Diquat has a long-standing history of use in global agriculture, vegetation control, and aquatic weed management. Its rapid burndown action and low soil persistence made it popular across multiple continents. However, regulatory landscapes vary, and importers must be aware of local restrictions.

Key Regional Markets:

• Asia (China, India, Southeast Asia): Widely used in rice, sugarcane, banana, and rubber plantations; often in pre-harvest or no-till weed management systems.
• South America (Brazil, Argentina): Popular for soybean and cotton desiccation. Still actively used in large-scale commercial farms.
• Africa: Utilized in diverse climates and crops; favored for broad-spectrum weed and aquatic vegetation control.
• Eastern Europe, CIS countries: Registered for both agriculture and infrastructure vegetation management.

Regulatory Notes:

• Banned or restricted in some EU countries due to environmental persistence and aquatic toxicity concerns.
• Still registered in many developing markets under FAO specifications.
• Buyers should always verify local MRLs, PHI guidelines, and registration requirements before importation or resale.

We provide assistance with product dossiers, GLP reports, and registration consultancy to support compliant market entry and distributor operations.

Frequently Asked Questions About Diquat Herbicide

1. What is diquat used for?

Diquat is a non-selective contact herbicide used for desiccation of crops, burndown of pre-plant vegetation, aquatic weed control, and non-crop area weed management. It’s particularly effective in situations where fast-acting results are needed.

2. How long does diquat take to work?

Visible symptoms like leaf wilting and browning appear within hours of application. Full desiccation is typically achieved within 1–3 days, depending on environmental conditions and target plant type.

3. Is diquat systemic?

No, diquat is not systemic. It does not move inside the plant. It only kills the parts it contacts, making thorough spray coverage essential for complete control.

4. Is diquat safe around crops?

Diquat can safely be used as a pre-plant or pre-harvest treatment, depending on the crop and timing. However, because it is non-selective, accidental drift can injure sensitive crops—use shielded sprays and observe buffer zones.

5. Can diquat be mixed with other herbicides?

Yes, diquat is commonly tank-mixed with products like glyphosate, paraquat, or atrazine to enhance control spectrum or add quick knockdown effects in IPM strategies.

6. What are the safety precautions for diquat?

Use proper PPE, avoid skin and eye contact, and strictly follow the label guidelines. Diquat can be harmful if swallowed or absorbed, so storage and handling protocols must be observed closely.

Partner with a Reliable Diquat Supplier for Scalable and Compliant Solutions

If you’re seeking a stable and experienced supplier for Diquat 20% SL or other formulations, we provide end-to-end support to meet your project goals. Whether you’re launching a private label, managing government vegetation contracts, or expanding your agricultural product line, our team is ready to deliver customized, compliant, and cost-effective solutions.

Why Work With Us:

• Full OEM/ODM Service: From formulation to packaging design
• Regulatory Support: Product dossiers, GLP data, compliance consulting
• Flexible MOQs: For trials, local market entry, or container-scale procurement
• Stable Production Capacity: Year-round availability with fast lead times
• Multi-market Experience: Serving clients in Southeast Asia, Africa, Latin America, and CIS regions

Let’s discuss how we can support your herbicide portfolio with high-performance diquat products and consistent technical service.