Understanding adjuvants and surfactants for improved pest management in ornamental crop production – Part II
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EmailUnderstanding what surfactants are and when to use them can improve pest management in ornamental crop production.
Many growers use the terms adjuvant and surfactant interchangeably, but they are not the same. All surfactants are adjuvants, but not all adjuvants are surfactants. In Part I of this article series, we discussed adjuvants and their types. In Part II, we are focusing on surfactants. Surfactants are a special category of adjuvants designed to change how spray droplets interact with plant surfaces.
Surfactant’s main functions are to:
- Improve spreading of spray droplets
- Enhance wetting of leaves and plant surfaces
- Promote better absorption of pesticides
In simple terms, surfactants help the pesticide “stick” and spread more evenly across the treated surface, making it more effective.
Types of surfactants
Surfactants are classified based on how they break into charged particles (ions) in water. There are three types of surfactants:
- Anionic surfactants. These surfactants carry a negative charge and are commonly used with contact pesticides, which act by directly hitting the pest rather than being absorbed by the plant.
- Cationic surfactants. These have a positive charge. They are generally not recommended for agricultural sprays as they may be phytotoxic and can damage treated plants or surfaces.
- Non-ionic surfactants. These surfactants have no electrical charge and are widely used with systemic pesticides, which are absorbed into the plant. Non-ionic surfactants are compatible with most pesticides and help improve penetration through plant cuticles.
Adjuvants and surfactants can significantly enhance pesticide performance, but only when used correctly. Not all adjuvants are needed for every application (Photo 1). Always read the label instructions, as it may recommend specific adjuvants or prohibit others. The label will also help you understand the role of each additive and then choose products that suit your specific growing needs. When in doubt, seek advice from Michigan State University Extension experts, product manufacturers or trusted agronomy professionals, as using the right adjuvant can improve pesticide performance, save money and protect crops.
