Chances are that if you have a pest problem you probably are going to use a pesticide to eliminate the pest. In addition, you are most likely going to use an adjuvant or surfactant in your pesticide spray.
An adjuvant is a chemical substance that is either added to a herbicide formulation or added to the spray tank to modify pesticidal activity or application characteristics. A surfactant, or surface acting agent, is a class of adjuvant comprised of chemical compounds that improve the emulsifying, dispersing, spreading, wetting, or other surface modifying properties of liquids.
When you use an adjuvant, some of the benefits include:
- Better mixing and handling of pesticide
- Increased pesticide droplet coverage on the target pest
- Better spray retention and droplet drying on the target pest
- Increased pesticide penetration of leaf cuticles, insect exoskeletons, etc.
- Increased cellular accumulation of pesticide thereby reducing environmental losses
There are a variety of adjuvant and pesticide products available for all manner of pest infestation scenarios. This makes picking the best pesticide and adjuvant combination challenging. For starters, interactions between adjuvants and pesticides are complex and depend on factors that include:
- Target pest surface characteristics
- Droplet characteristics
- Adjuvant type
- The chemical form of the herbicide
- Environmental conditions
With a clear understanding of adjuvant and pesticide interactions, a spray solution may be formed that will have one or more of the following nine functions while providing safe and effective application:
- Wetting of pest – necessary to provide good coverage and retention of spray solution on the target pest.
- Modifying rate of evaporation of spray – to help retain spray solution in aqueous form or to dry rapidly, depending on circumstances.
- Improving weatherability of spray deposits – to help retain pesticide spray on target pest considering heavy dew, rainfall, or sprinkler irrigation.
- Enhancing penetration and translocation – to improve pesticide absorption and performance.
- Adjusting pH of spray solutions and deposits – to overcome mildly alkaline conditions found in some water and pest surfaces and prolong the life of pesticide spray.
- Improving uniformity of deposit – enhanced coverage of target pests where needed for improved control.
- Compatibility of mixtures – to enable the mixture of pesticides with liquid fertilizer, for example, in simultaneous applications.
- Safety of the crop – to ensure the proper adjuvant is used to make the pesticide less phytotoxic to the crop.
- Reducing drift – to thicken the spray solution by increasing viscosity and thereby protect non-targets and the environment.