The present invention relates to 4-substituted phenylamidine derivatives of the general formula (I), wherein R5-R6, ArA4, D, G, B, Q and an integer m have the meanings as defined in the description. The invention further relates to methods for their preparation and use of said compounds for controlling undesired phytopathogenic microorganisms, and agents for said purpose, comprising said phenylamine derivatives. This invention further relates to a method for controlling undesired phytopathogenic microorganisms by application of said 4-substituted phenylamidine derivatives of general formula (I) to such undesired microorganisms and/or to their habitat, according to the invention.