Pesticide adjuvant

Pesticide adjuvants are chemicals applied alongside pesticides to enhance the effectiveness of the active ingredient. They are used together with the pesticide itself (i.e. the active ingredient) to produce the mixture (pesticide formulation) which is then applied. The adjuvants do not control or kill pests, but they improve such properties as spreading, penetration, droplet size or other characteristics. Over twenty different types of adjuvants are on the market, including surfactants, oils, compatibility agents, buffering and conditioning agents, defoaming agents, deposition agents, drift control agents, and thickeners.

Adjuvants may be part of an already formulated pesticide as purchased (in-can adjuvants), or may be added separately when the spray solution is being prepared (tank mix adjuvant). Nearly all pesticides are sold by the manufacturers already formulated, and this formulation is effective, but not for all applications. Those applications may then profit from an in-tank adjuvant.

Annual worldwide adjuvant sales are estimated to be worth more than $1.5 billion, most of which is used by manufacturers in-can.

The use-rate on the pesticide label is mandatory by law. If an adjuvant improves the effectiveness of a pesticide, so that the farmer feels confident in spraying a lower amount, this is only legally allowed if the information on the pesticide label allows it.