Know Your Formulation (Part 4) – Suspension Concentrates and Flowables

Suspension Concentrate pesticide formulations are liquid formulations that consist of concentrated active ingredients (usually finally milled solids) combined with liquid suspension agents that, when mixed with water, allow for a uniform sprayable mixture. They are also sometimes referred to as Flowable (F) formulations.

SC Herbicides & Fungicides: A Safer Alternative for Easier Weed & Disease Control

SC formulations are somewhat viscous, opaque liquids. Many are white or off-white in color. Since they contain no petroleum solvents, they are generally non-volatile, have little to no odor, and don’t react with metals or plastics, all sprayer-friendly attributes. In addition, concerns for dermal exposure are lessened, and spill clean-up is simplified with products of this type.

📸: BASF employee/Featuring two examples of Suspension Concentrates. Left: Armezon^® herbicide. Right: Zidua^® SC herbicide.

Beyond Mixing: Understanding the Pros & Cons of SC Formulations

When added to water, they do not form an emulsion but instead form a suspension. Since they are not water-soluble, they will settle out if not agitated. SCs can leave residues, and over time, buildup can occur. This can lead to nozzle or screen plugging, particularly if drying occurs. Residues in tanks can be more difficult to remove.  

📸: BASF employee/Featuring residue build up in spray bottle from SC formulation.

📸: BASF employee/Featuring nozzle plugging after application of SC formulation.

SC vs. Fertilizer Carriers: Why Mixing Can Be a Recipe for Disaster

SC formulations are designed to be applied with water carriers, and most are not compatible with liquid fertilizer carriers. Attempting to directly mix SCs in liquid fertilizer often results in flocculation or curdling, making such mixes un-sprayable. 

📸: BASF employee/Featuring incompatible mix of SC herbicide and fertilizer carrier.

Popular Herbicides & Fungicides Available in SC Formulations 

Many currently available herbicides and fungicides are formulated as suspension concentrates:

• Armezon^® herbicide,
• Sharpen^® herbicide,
• Zidua^® SC herbicide,
• Headline^® AMP fungicide,
• Priaxor^® fungicide,
• Revytek^® fungicide,
• Veltyma^® fungicide

These are some examples from BASF. Atrazine 4L and nearly all atrazine pre-mixes are also SC formulations.

Mixing & Tank-Mixing SC Herbicides & Fungicides: The Right Order Matters 

Many of these products are sprayed alone in water and will be the first product added to the sprayer, followed by any spray adjuvants. If tank mixing, they are the first liquid formulations that should be added, after dry formulations.

Before mixing components, always conduct a compatibility jar test. Always consult respective product labels for specific mixing instructions. The most restrictive label applies.

Always read and follow label directions. Grow Smart, Armezon, Sharpen, Zidua, Headline, Priaxor, Revytek, and Veltyma are registered trademarks of BASF. All other trademarks are the property of their respective owners and use of any such trademark does not imply any affiliation with or endorsement by its owner. © 2024 BASF Corporation. All rights reserved.