What is described is use of a polymeric solubilizer for increasing the soil mobility of a sparingly soluble insecticide, said polymeric solubilizer having the property that the active insecticidal ingredient in a 1% by weight aqueous solution of the polymeric solubilizer at 25° C. and 1.01325 bar has a solubility at least forty times higher than under the same conditions in pure water, and wherein the active ingredient:solubilizer weight ratio is ≦1.