Interest in replacing petroleum oil derivatives in adjuvants with value- added agricultural commodity products has spawned considerable research, development, and marketing effort. The benefits derived from adding ammonium salts to counter the effects of cationic such as Ca, Mg, and Fe in hard water are obvious and have triggered interest in combination adjuvants that supply the ammonium and also the surfactant portion of the activator adjuvants. Interest in nonylphenol ethyoxlates has waned after implication of nonylphenol, a breakdown product, as a endocrine modifier. Adjuvants which reduce drift have received renewed interest, especially with the development of some of the new herbicide-resistant crops. Drift is primarily a function of droplet size and wind.
Adjuvants can alter droplet size and spray retention.
Current research clearly shows that adjuvants need to be matched to the specific herbicide, weed, and environmental conditions. The 5th Edition of this Compendium of Herbicide Adjuvants contains 391 entries from 36 companies. The 1st Edition of this Compendium was assembled in 1992 with 76 entries from 22 companies. The increase in the number of adjuvants from 1992 to 2000 is amazing and probably reflects several developments. First, substantially more postemergence herbicides are now used than in 1992, with most requiring one or more adjuvants.