Agrochemical Formulation Guide: SC, SE, EC, WDG and SL

Why formulation type matters

The same active ingredient can be delivered as an emulsifiable concentrate (EC), suspension concentrate (SC), suspoemulsion (SE), water-dispersible granule (WDG), soluble liquid (SL), emulsion in water (EW), or oil dispersion (OD). Each code defines the physical form, dilution behaviour, regulatory dossier, storage stability, and the surfactant package required for shelf life and field performance. A pyrethroid insecticide formulated as a 2.5% EC in aromatic solvent behaves entirely differently from the same active in a 10% SC — even though both are diluted into the same spray tank before application.

Indian generic manufacturers export all major formulation codes globally, from Latin America and Africa to Southeast Asia and the Middle East. Local emulsifier and dispersant supply shortens development cycles, reduces import dependency, and supports cost-competitive tenders. Venus Ethoxyethers manufactures nonionic emulsifiers, anionic dispersants, silicone spreaders, wetting agents, and defoamers for every code described below, with technical support for CIPAC-aligned stability testing and scale-up from pilot to commercial batch.

Formulation type comparison

See our dedicated emulsifiable concentrates guide for EC emulsifier design in depth, including Ca-DDBS pairing, HLB matching, and CIPAC MT 36 dilution stability.

Emulsifiable concentrates (EC)

EC formulations remain the dominant delivery form for lipophilic insecticides, fungicides, and many herbicides. The active is dissolved in organic solvent together with an emulsifier package; on dilution in the spray tank, the system spontaneously forms a fine oil-in-water emulsion. Typical emulsifier blends pair calcium dodecylbenzene sulfonate (Ca-DDBS) with fatty alcohol ethoxylates such as C9–C11 oxo alcohol, 6 EO, or tridecyl alcohol ethoxylate at total emulsifier levels of 5–15% in the concentrate.

Solvent selection drives emulsifier requirements. Aromatic solvents (Solvesso 100/150 equivalents) suit pyrethroids and organophosphates; polar solvents such as cyclohexanone or NMP appear in herbicide ECs where actives have limited aromatic solubility. Venus supplies pre-balanced emulsifier blends through the emulsification range and supports HLB matching for new active-solvent combinations.

Worked example: 25% deltamethrin EC

• 25.0% deltamethrin technical (min. 98%)
• 8.0% emulsifier blend (4% Ca-DDBS + 4% C9–C11 alcohol, 6 EO)
• 67.0% aromatic solvent (Solvesso 100 equivalent)

Dissolve emulsifiers in solvent at 45°C, add active under agitation, mix until clear, cool and filter. Target: CIPAC MT 36 pass; cold test 0°C/7 days pass; active content 25.0 ± 1.0%.

Suspension concentrates (SC)

SC formulations suspend micronized active particles in water with dispersants that prevent aggregation, sedimentation, and crystal growth. Typical components include: wetting agent (0.5–2%) to aid milling and redispersion; dispersant (2–6%) — often phosphate esters, sulfonates, or block copolymers; antifreeze (propylene glycol, 5–10%); thickener (xanthan gum, 0.1–0.3%); and defoamer (0.1–0.5%).

Milling to D90 below 5 µm is critical. Poor particle size distribution causes nozzle blocking, inconsistent field dose, and visible residue on treated crops. Wet milling with zirconia or glass media is standard; the wetting agent must reduce surface tension enough to allow efficient comminution without excessive foam. Venus phosphate esters and dispersing agents are used in herbicide and fungicide SC platforms exported from India.

Worked example: 250 g/L azoxystrobin SC

• 250 g/L azoxystrobin technical (wet milled to D90 < 3 µm)
• 3.0% phosphate ester dispersant
• 1.0% C9–C11 alcohol, 7 EO (wetting agent)
• 8.0% propylene glycol (antifreeze)
• 0.2% xanthan gum (suspending aid)
• 0.3% silicone defoamer
• Balance: demineralized water

After milling, verify viscosity (typically 200–800 cP), 14-day heat stability at 54°C, and centrifuge or tumble test for sedimentation. Venus defoamers help control foam during milling and filling operations.

Suspoemulsions (SE)

SE combines a dispersed solid phase with an emulsified oil phase in one aqueous concentrate — common for combination products (e.g. fungicide + insecticide), actives with different solubility profiles, or when one component is oil-soluble and another is solid. The surfactant package must stabilize both the solid–water and oil–water interfaces simultaneously without competitive adsorption that collapses either phase.

A typical SE uses: lipophilic emulsifier for the oil droplets (HLB 9–11); hydrophilic dispersant for solids (phosphate ester or sulfonate); and often a polymeric stabilizer or additional nonionic to bridge both interfaces. Compatibility between components is verified through accelerated heat/cold storage, dilution stability per CIPAC methods, and dynamic shake tests simulating farmer tank mixing.

SE surfactant package example:

Emulsion in water (EW)

EW formulations contain the active dissolved or dispersed in fine oil droplets pre-emulsified in water. Unlike EC, the farmer receives a ready-made emulsion rather than a solution that emulsifies on dilution. EW avoids aromatic solvent in the packaged product, which can simplify hazard classification, though manufacturing requires high-shear homogenization and robust emulsion stabilizers. Nonionic emulsifiers with HLB 12–15 and anionic co-emulsifiers are typical; Venus supports EW development alongside EC and SC platforms on the agrochemical applications page.

Water-dispersible granules (WDG)

WDGs are dry granules that disintegrate and disperse when added to the spray tank. Fast wetting is essential — farmers expect complete dispersion within 60 seconds of agitation under field conditions. Nonionic wetting agents (C9–C11 alcohol ethoxylates, tridecyl alcohol ethoxylates) at 1–3% in the granule formula are standard. The wetting agent may be incorporated via pre-mix with the active, spray-dried onto the powder blend, or added during extrusion.

Extrusion or pan granulation processes require surfactants that survive heat drying without losing wetting power. Lignosulfonate and PVP binders are common; surfactant compatibility with these binders must be confirmed. Venus supplies wetting agents compatible with WDG binders used in Indian export formulations targeting tropical and temperate markets.

Worked example: 75% WG herbicide granule

• 75% active ingredient (technical, micronized)
• 2.0% C9–C11 alcohol, 7 EO (wetting agent)
• 1.5% lignosulfonate (binder/dispersant)
• 0.5% silicone defoamer
• Balance: filler (kaolin or diatomaceous earth)

Target: complete dispersion in 342 ppm hard water within 60 s; no visible granule residue after 5 min agitation.

Soluble liquids (SL)

SL formulations dissolve the active directly in water, sometimes with co-solvents or hydrotropes. Systemic herbicides such as glyphosate salts (isopropylamine, potassium, or ammonium) are classic SL products. While in-can surfactant demand is lower than EC or SC, tank-mix adjuvants and in-can stabilizers still rely on alcohol ethoxylates and amine-based hydrotropes. Glyphosate efficacy is often enhanced by ammonium sulfate tank-mix — a separate mechanism from surfactant wetting — but dedicated glyphosate adjuvants based on tallow amine ethoxylates or silicone blends remain common in certain markets.

Oil dispersions (OD)

OD formulations suspend solid actives in an oil continuous phase, often methyl ester or vegetable oil bases. They suit actives with poor water stability or when oil-based delivery improves leaf penetration. Dispersants must function in non-aqueous media — typically oil-soluble surfactants with low HLB. OD is growing as formulators seek alternatives to aromatic solvent ECs; Venus dispersants and emulsifiers support OD development alongside traditional EC platforms.

Stability testing checklist

Regulatory dossiers and export tenders require documented stability data. The following tests are standard across CIPAC, FAO, and national authorities:

• Heat storage: 54°C for 14 days (tropical shelf life simulation)
• Cold storage: 0°C for 7 days (no crystallization, separation, or viscosity change)
• Centrifuge or tumble test: SC/SE/CS sedimentation after accelerated separation
• CIPAC MT 36: dilution stability for emulsion types in 342 ppm CaCO₃ hard water
• Hard-water compatibility: 500–1000 ppm CaCO₃ where field water is known to be hard
• Jar test: compatibility with common tank-mix partners (fertilizers, copper fungicides, adjuvants)
• Freeze–thaw: three cycles for temperate market registration

Failure at any stage leads to phase separation, nozzle blocking, creaming in the spray tank, or poor field efficacy. Root causes are often incorrect surfactant selection, insufficient dose, or incompatibility between formulation components.

Choosing surfactants by formulation

Indian manufacturing advantage

India is a global hub for generic agrochemical production, with formulation plants clustered in Gujarat, Maharashtra, Andhra Pradesh, and Telangana. Local surfactant supply from Venus Ethoxyethers in Goa reduces lead times, avoids import duties and currency risk, and supports custom EO blends for export formulations targeting specific climate and water conditions. With dedicated alkoxylation reactors and 24/7 R&D, Venus provides samples, formulation guides, and scale-up support for EC, SC, SE, WDG, and SL platforms.

Contact Venus for emulsifier samples, dispersant recommendations, and partnership on next-generation formulation development via contact. Explore the full portfolio on agrochemical applications and read related guides on silicone spreaders and pesticide wetting adjuvants.