Adjuvants

An overview of the adjuvants in use in Region 8.

BY Ali Rehman Afridi

Adjuvants

Any material added to a pesticide mixture to modify its behavior; includes wetting

agents, spreader stickers, other surfactants, penetrants, and drift control

agents

Adjuvants – some definitions

Polar vs. non-polar

Polar compounds are compounds which have, due to their structure, have a definite imbalance in charge – resulting in a positive and a negatively charged end - +

Polar bear?

Adjuvants – some definitions

Polar vs. non-polar

Non-polar compounds are compounds which have evenly distributed charge throughout their molecules

Adjuvants – some definitions

R +

-Polar Non-polar

Adjuvants – some definitions

Polar vs. non-polar

Polarity in a chemical aids in spreading the chemical over a polar surface or in penetrating one

Adjuvants – some definitions

Ionic vs. non-ionic

In solution ionic molecules separate into positively and negatively charged subparts (ions) while non-ionic molecules do not

Adjuvants – some definitions

Ionic vs. non-ionic

R +

-

Ions from an ionic compound

Non-ionic molecule

Adjuvants – some definitions

Ionic vs. non-ionic

Ions from an ionic compound can interfere with the activity of a polar or an ionic pesticide while non-ionic compounds do not

Adjuvants

Surfactant

Any material added to a pesticide formulation which is designed to modify the surface characteristics of the target

organism

Surfactants

Wetting Agent

Any material added to a pesticide mixture which serves to make the surface

“wetter” so as to allow more rapid spread of the pesticide on the target –

often called a ‘spreader’

Without wetting agent

With a wetting agent

Wetting agents

Penetrant

Any material which modifies the target surface in a way which allows more

rapid penetration of the surface of the organism by the pesticidal formulation

Penetrants

Mineral oil Napthenic oil

Diesel oil

Penetrants

Vegetable oil Organic silicone

Penetrants

Products designed to create invert emulsions (oil in water)

Spreader

Any material added to a pesticide formulation which improves the

formulations ability to rapidly form a film on the target surface – generally interchanged with “wetting agent”

Sticker

Any material added to a formulated pesticide which improves the ability of the pesticide to adhere to the target

surface

Stickers

Drift Control Agent

Materials added to a mixture to increase the size of droplets and decrease the tendency of the pesticide to drift off-

target

Drift control agents

Materials added to a formulation which marks a treated stem so that later identification of those treated vs. not treated is simplified Dyes in either amine or ester formulations

are the most common pattern indicators

Pattern indicators