The present invention teaches a surfactant blend composition of at least one alcohol alkoxylate and at least one alkoxylated quaternary, and its use as an adjuvant for auxin-based pesticides. The pesticidal composition employing the surfactant blend composition of the invention realizes an efficacy that is unexpectedly superior to similar pesticidal compositions which employ only the individual surfactant components. The composition of the present invention is useful as a tank side additive, or as a component in the mention pesticidal formulations.