Tankmix additive concentrates containing a phosphate ester and/or polymeric surfactant and a triglyceride fatty acid ester and the use of aqueous herbicide spray mixtures incorporating such tankmix additive concentrates are described. The tankmix additive concentrates described herein include from 1 to 50 weight percent of a phosphate ester surfactant, a polymeric surfactant, or mixtures thereof, and from 1 to 90 weight percent of a triglyceride fatty acid ester. The tankmix additive concentrates form a stable emulsion upon dilution into a pesticide spray mixture.