Since aerial applications normally are made with highly concentrated spray mixtures, spray nozzles that create small droplets are often used. Since small droplets can travel farther than larger droplets, some drift retardants work by increasing mean droplet size. Extenders are adjuvants that can extend the useful life of a spray chemical. They work by increasing the chemical's adhesion to the leaf, by reducing any factor that can diminish chemical effectiveness, or by enhancing chemical weatherability. Since many pesticides are broken down by ultraviolet light, some extenders have the ability to intercept ultraviolet light.
Organosilicon surfactants are a new class of surfactants.
Generally they are more effective per unit of active ingredient than the more traditional surfactants. Penetrants are adjuvants that help chemicals penetrate plants. Spreaders are surfactants. See Surfactant . Spreader-stickers are compounds that perform two functions at the same time.