The invention relates to aqueous active ingredient compositions in which the active ingredient or ingredients are present in the form of an aqueous dispersion of finely divided polymer-active ingredient particles which comprise at least one water-insoluble polymer P, at least one surface-active substance, and at least one organic active crop protection ingredient which is present in the polymer particles and has a solubility in water of not more than 5 g/l at 25° C./101.325 hPa, in which the polymer-active ingredient particles have an average particle diameter, determined by dynamic light scattering, in the range from 300 to 1200 nm, preferably in the range from 310 to 1000 nm, and more particularly in the range from 320 to 800 nm, the polymer P being a polymer of ethylenically unsaturated monomers M which comprise 0.1% to 10%, more particularly 0.2% to 7%, and especially 0.3% to 5%, by weight, based on the total amount of the constituent monomers M of the polymer P, of at least one monoethylenically unsaturated compound M2 which is selected from monoethylenically unsaturated sulfonic acids, monoethylenically unsaturated phosphonic acids, and monoethylenically unsaturated phosphoric monoesters, and also the salts thereof, the amounts in % by weight being based on the acid form of the monomer M2.The invention also relates to a process for preparing them and to the use of active ingredient compositions of this kind.
