The present invention relates to the promotion of a continuous chemical barrier of a soil-born invertebrate pest control agent in soil in a locus where soil-borne invertebrate pests are suspected or known to exist. In particular the present invention relates to compositions of liquid soil-borne invertebrate pest control agents and selected adjuvants wherein the adjuvant improves the downward and lateral movement in the soil of the soil-born invertebrate pest control agent contained in the liquid soil-borne invertebrate pest control agent. The invention set forth herein finds particular utility with soil-born invertebrate pest control agents with a water solubility of 3 ppm, or less, such as bifenthrin.