The present invention relates to 3-substituted phenylamidines of the general formula (I), to a process for their preparation, to the use of the amidines according to the invention for controlling unwanted microorganisms and also to a composition for this purpose, comprising the phenoxyamidines according to the invention. Furthermore, the invention relates to a method for controlling unwanted microorganisms by applying the compounds according to the invention to the microorganisms and/or their habitat.