Snapshot

Surfactants (surface active agents) are a type of adjuvant designed to improve the dispersing/emulsifying, absorbing, spreading, sticking and/or pestpenetrating properties of the spray mixture. Pure water will stand as a droplet, with a small area of contact with the waxy leaf surface. Water droplets containing a surfactant will spread in a thin layer over a waxy leaf surface. Because postemergence herbicide effectiveness is greatly influenced by plant factors such as age, size and the growing conditions encountered before application, herbicide performance can vary. A way to minimize the variations in postemergence herbicide performance is to use an adjuvant or surfactant in the spray solution.

Adjuvants, specifically surfactants, generally improve the effectiveness of postemergence herbicides. Typically, surfactants are not added to herbicides that are soil applied (pre-emergence). Adjuvants usually have multiple functions in relation to pesticide ef?cacy.  Increasing the foliar uptake of active ingredients is of particular importance for herbicides, growth regulators, and defoliants. Therefore, the choice of the adjuvant in an agrochemical formulation is crucial. 

Adjuvants are fascinating compounds. Typically showing no biological activity at all on their own, they help to exploit the full biological potential of many active ingredients. They can be absolutely necessary for some actives or to preserve activity, for example, under unfavourable environmental conditions or adverse water quality.

Examples of adjuvants include:

• Compatibility agents

• Drift retardants

• Suspension aids

• Spray buffers

• Surfactants