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  • What Are Adjuvants?

     

    An adjuvant is a chemical designed to improve the activity of pesticides and overcome the factors that limit pesticide performance

    The activity of an adjuvant can either enhance the biological efficacy of the pesticide or modify the physical characteristics of the spray solution.

    Why do we need adjuvants?

    The application of crop protection products is a highly inefficient process. It is estimated that only around 15% of applied pesticide reaches its target and as little as 0.1% reaches its site of action. This means that 85% of pesticide misses the target, going into the environment as spray drift, leaching into the soil or into ground water.

    This leads to higher costs to the farmer, potential damage to the environment and a poor public image.Farmers today are under pressure to produce crops cost-effectively, but with the environment very much in mind. They need to justify each input. Farmers are looking for ways to apply lower spray volumes per unit area in the most cost-effective way. From a practical viewpoint with the limited number of spray days available, they may also be unable to apply the products under the most optimal conditions.

    How can adjuvants help the end-user?

    • enhancing biological performance of the active ingredient
    • improving the speed of action and target spectrum
    • aiding coverage, penetration and uptake into the plant
    • improving rainfastness, particularly in showery weather
    • reducing or eliminating variables of spray performance such as dry or cold conditions
    • extending the spray window or increasing the size of target controlled
    • adjusting the pH of the spray solution for optimum availability
    • helping to reduce costs through better performance
    • improving crop safety

    How can they help the environment?

    • improving the performance of reduced rates and so reducing overall pesticide loading
    • having an intrinsically low biological activity
    • reducing drift and loss of pesticide to soil, minimising impact on non-targets
    • help to reduce leaching of pesticides in the soil environment

     

  • Adjuvants In The Spray Process


    Spray adjuvants and additives have the ability to maximise pesticide and trace element performance throughout the various stages of the spray process

    Improve activity within the spray tank by:

    • Improving chemical compatibility
    • improving water quality (adjust pH (buffering), removing antagonistic calcium and magnesium ions
    Improve spray quality by:

    • reducing drift
    • reducing evaporation of the spray mixture
      Improve spray retention by:

    • reducing bounce
    • improving coverage (of waxy leaves, upright grass-weeds)
    • improving spray distribution (in dense crops or through the soil structure)
    Improve spray penetration, allowing:

    • improved uptake through waxy cuticles
    • improved activity at lower temperature
      Improve translocation of the spray. This will:

    • improve speed of kill
    • improve activity against ‘difficult-to-control’ weeds (target spectrum)
    The use of adjuvants is growing because they are often the best way to increase pesticide efficacy, especially where reduced rates are routinely used, in difficult growing conditions (e.g. low temperatures, resistant weed/disease situations), where bigger weeds have to be controlled, and to minimise adverse environmental impact.

    Sound development, field trials and marketing have ensured that adjuvants have come of age and are recognised as playing an important role in optimising the performance of pesticides.




  • Adjuvant Chemistry

    Adjuvants have been used with pesticides for over 40 years, initially with the use of mineral and paraffinic based adjuvant oils and standard spreaders. Over the years new improved adjuvant chemistry has been introduced and Interagro has been at the forefront of developing new adjuvant technology, with the introduction of methylated vegetable oils, organosilicones, alkoxylated amines and pyrrolidone based adjuvants.

    Kantor is the latest result of this development process. It is based on a brand new class of adjuvant chemistry – the alkoxylated triglycerides – which gives Kantor a comparatively safe and ‘green’ environmental profile, but also importantly gives Kantor its unique penetrative properties.

    Adjuvant Chemistry

    Examples

    When Initially Developed

    Mineral / Paraffinic Oils

    Actipron

    1970s

    Lecithin

    LI-700

    1980s

    Synthetic Latex

    Bond

    1980s

    Organosilicones

    Slippa, Silwet L-77, Rhino

    1990s

    Methylated Vegetable Oils

    Toil

    1990s

    Alkoxylated Amines

    Spartan

    Late 1990s

    Pyrrolidones

    Banka

    Late 1990s

    Alkoxylated Triglycerides

    Kantor

    2006 - 2009






  • Adjuvant Glossary

     

    Anti-evaporants

    These reduce the evaporation rate of a spray mixture during and/or after application.

    Buffering agent

    These cause a solution to resist change in pH.

    Humectants

    These increase the equilibrium water content and increase the drying time of a water-based spray deposit by drawing moisture from the environment or resisting evaporation.

    Penetrants

    Penetrants are materials that enhance the ability of an agrochemical to enter or penetrate a surface. They work by disrupting the waxy cuticle thereby allowing active transport across the leaf.

    Spreaders

    These adjuvants increase the area that a droplet of a given volume of spray mixture will cover on any target without affecting the concentration of the active ingredient. Organosilicone spreaders allow spray droplets to cover an area 2-3 times of that covered by the initial spray.

    Stickers

    These assist the spray deposit to adhere or stick to the target and can be measured in terms of wind, water or mechanical action.

    Super Spreaders

    This chemistry reduces surface tension dramatically so that maximum wetting and spreading over the leaf is achieved. The increase in spreading can be as high as 10-100 times the original droplet size.

    Water conditioner

    These reduce the effect that hard water ions in spray water have on pesticide performance.

    Wetters

    These are substances that reduce surface and interfacial tensions and cause the spray solutions to make better contact with treated surfaces. Wetters make the droplet less spherical so that the contact angle decreases and the droplet flattens on the leaf. They can be divided into anionic, cationic and non-ionic.