The present invention relates to novel imidazole derivatives of formula (I) as active ingredients which have microbiocidal activity, in particular fungicidal activity: wherein R1 is halogen, C1-C4alkyl or C1-C4haloalkyl; R2 is an optionally substituted aryl or heteroaryl; R3 is halogen; R4 is hydrogen, halogen, C1-C4alkyl, C1-C4haloalkyl, hydroxyl, C1-C4alkoxy, OR6, C1-C4haloalkoxy or cyano; R5 is halogen; R6 is hydrogen, C3-C7 cycloalkyl, C3-C10 alkylcycloalkyl, C1-C6 haloalkyl, C2-C6 alkenyl, C2-C6 haloalkenyl, C3-C7 cycloalkenyl, C2-C6 alkynyl, C2-C6 haloalkynyl or C2-C6 alkyloxyalkyl; X is N or C(R); and R is hydrogen, halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy, C1-C4haloalkoxy or cyano; or an agrochemically usable salt form thereof; provided that when X is C(R), R2 cannot be an optionally substituted aryl.