Welcome to Adjuvant 101: What is an adjuvant? Let’s start with the basics. Adjuvants are not new – in fact, they have been around as long as herbicides. However, with many new traits and herbicide technologies entering the market, adjuvants are getting a lot more discussion, as they rightfully should. But if you have found yourself confused as to what an adjuvant is, what it does, and how to use it properly, you are not alone. Many questions still exist about this growing product category, perhaps because the term is so broad or because adjuvants can serve many functions. Garnering a better understanding of what adjuvants are and how they are used, however, can prove to be a powerful asset to any crop protection plan.

What is an Adjuvant?

An adjuvant is a broad term for any substance in a spray solution used to improve pesticide activity or application characteristics. Adjuvants help to make chemical, environmental, and physical factors work more efficiently together to increase crop protection product performance and can perform one or several functions, including:

• Improved pesticide coverage, adherence, and penetration to a pest
• Water conditioning
• Increased water droplet size for less drift
• Additional stability, solubility, and compatibility of a solution
• Decreased foam in a tank mix
• Aid in field marking

While a broad and growing product category, adjuvants can be broken into two groups based on the ways they improve crop protection: activator adjuvants and special purpose/utility adjuvants.

Activator Adjuvants

Activator adjuvants get their name from what they do: activate crop protection products. These adjuvants enhance the biological activity of a specific crop protection product for increased absorption and penetration rates, allowing for better weed, insect, or disease control. This group of adjuvants includes:

• Surfactants: Known as wetter-spreaders, surfactants help spread herbicide over the entire surface of a pest by reducing the surface tension between the spray solution and the target surface.
• Oil concentrates: Allow active pesticide ingredients to penetrate a target pest more effectively.
• Liquid fertilizer solutions: Increase a fertilizer’s absorption within a targeted pest while enhancing the physical characteristics of a spray solution.

To read more about activator adjuvants check out our blog “Get to Know Adjuvants: Activators”.

Special Purpose/Utility Adjuvants

Special purpose/utility adjuvants contain a broader list of adjuvant types that all serve to make tank mix ingredients work better together. They work by altering the physical characteristics of the spray solution for maximum performance while correcting issues in the tank mix that could negatively affect spray applications. This group of adjuvants includes:

• Drift control agents: Help improve the precise placement of a pesticide spray by increasing the spray droplet size.
• Deposition aids: Known as stickers, deposition aids increase the ability of water-soluble pesticide particles to stick to a plant’s surface and create a waterproof coating.
• Compatibility agents: Reduce clumps and uneven chemical distribution in the tank to mitigate application problems.
• Water conditioners: Address the hardness, acidity, or alkalinity of water in the tank to ensure an effective crop protection solution.

To read more about special purpose/utility adjuvants check out our blog “Get to Know Adjuvants: Special Purpose/Utility”.

Multifunctional Adjuvants

While some adjuvants only perform one function, multifunctional adjuvants can be used to perform several functions simultaneously, according to product label needs. Multifunctional adjuvants offer added convenience and can help growers avoid specific compatibility issues, which can be costly and time-consuming.

To read more about selecting the right adjuvant, check out our blog “How To Select the Right Adjuvant”.

CHS Agronomy develops and offers a full range of activator, special purpose/utility and multifunctional adjuvants, from drift inhibitors and buffers to compatibility agents, deposition aids, and surfactants to enhance herbicide, fungicide, and insecticide technologies.

For more information about adjuvants, download the CHS Agronomy white paper "Using Adjuvants to Improve Crop Protection Performance". For a listing of available adjuvants visit the CHS Agronomy website.