The present invention relates to a method of applying an aqueous, pesticide-comprising dispersion of a polyurethane which is composed of diisocyanates (a) and diols (b), to plants or plant parts. Furthermore, the invention relates to an aqueous, pesticide-comprising dispersion of a polyurethane which is composed of diisocyanates (a) and diols (b). It furthermore relates to the use of the dispersion for controlling phytopathogenic fungi and/or undesired plant growth and/or undesired attack by insect or mites and/or for regulating the growth of plants, by allowing the dispersion to act on the respective pests, their environment and/or the plants to be protected from the respective pest, on plant parts, on the soil and/or on undesired plants and/or on the useful plants and/or their environment.