A copolymer obtainable by polymerization of a) at least one compound of the formula (I) (monomer α) where R1 and R2, independently of one another, are in each case H or CH3, R3 is C6-C10-aryl or C7-C12-aralkyl which can carry one or more identical or different C1-C9-alkyl and/or C1-C5-alkoxy substituents, and n is an integer from 0 to 100, b) at least one compound chosen from the group of N-vinylamides, N-vinyllactams, N-vinylimines and N-vinylamines with 2 to 15 carbon atoms (monomer &bgr;), c) if appropriate one or more different difunctional crosslinker components and d) if appropriate one or more different regulators and e) if appropriate one or more further copolymerizable components (monomer γ) is useful for increasing the systemicity of a pesticide.