Improving pesticide effectiveness is a key role of adjuvants, said Kai Umeda, UA area extension agent, Maricopa County.

“Adjuvants are added to the spray tank to improve the physical characteristics of the spray mixture and/or to modify the action of an applied agrichemical,” Umeda said.

Adjuvants are either added to the spray mix in the tank or come already mixed in the pesticide container as an inert ingredient.

Commonly-used adjuvants include activators, stickers, spreaders, wetters, and extenders. Stickers help a sprayed pesticide to stick to the leaf surface versus dripping off. Other types can break down the leaf’s waxy cuticle layer to allow the chemical to more effectively enter the plant. A buffer adjuvant can increase pesticide performance when less quality water is in the tank mix.

Adjuvants are important pesticide enhancers but may also come at a cost.

“The main thing is do your homework to watch the bottom line,” Umeda said.

Farmers should consult their pest control adviser and chemical dealer to learn more about the wide range of adjuvants available. Umeda says compare similar products to get the best deal. Experience over time will determine which products perform better than others. Some adjuvants are “all-in-one” and can fulfill multiple purposes.

“Adjuvants improve the economics of pesticide applications,” Umeda said. “Do not cut corners and eliminate needed adjuvants from the tank to reduce costs.”

Another good resource for adjuvant information is through a voluntary certification program developed by the Chemical Products and Distributors Association. Online information is located at

When applying pesticides, Umeda urges applicators to always use personal protective equipment. At the minimum, most pesticide labels instruct applicators to at least wear long-sleeve shirts, long pants, plus shoes and socks. Sealed goggles are critical to protect the eyes. Full body Tyvek-type suits provide a good barrier to eliminate chemical absorption into the body.

Umeda says use a respirator to keep fumes and volatiles out of the lungs when working with insecticides and fumigants. Use the appropriate respirator cartridge for the specific chemical. Conduct a ‘fit check’ to ensure the respirator is tightly sealed around the face. Wear rubber boots if walking in spray.