Fuente: WIPO "tomato" A method for improving rainfastness of an agrochemical active ingredient comprises applying to a plant surface a composition containing at least one agrochemical active ingredient and a rainfastness enhancing agent, the rainfastness enhancing agent comprising an aqueous polymer dispersion, obtainable by radical aqueous emulsion polymerization of a mixture comprising a) ethylenically unsaturated monomers M, with M comprising at least one vinyl ester M1, and at least one (meth)acrylic acid ester M2, b) a carboxyl-groups-containing compound CGCC, c) at least one non-carboxylated saccharide and/or polysaccharide S, and d) at least one emulsifier selected from non-ionic and anionic surfactants, wherein wherein the dispersion has a pH of up to 4. The aqueous polymer dispersion is useful for enhancing the rainfastness of agrochemical active ingredients.