The present invention relates to novel imidazole derivatives of formula I as active ingredients which have microbiocidal activity, in particular fungicidal activity: wherein R 1 is halogen, C 1 -C 4 alkyl or C 1 -C 4 haloalkyl； R 2 is an optionally substituted aryl or heteroaryl； R 3 is halogen； R 4 is hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, hydroxyl. C 1 -C 4 alkoxy, OR 6 , C 1 -C 4 haloalkoxy or cyano； R 5 is halogen； R 6 is hydrogen, C 3 -C 7 cycloalkyl, C 3 -C 10 alkylcycloalkyl, C 1 -C 6 haloalkyl, C 2 -C 6 alkenyl, C 2 -C 6 haloalkenyl, C 3 -C 7 cycloalkenyl, C 2 -C 6 alkynyl, C 2 -C 6 haloalkynyl or C 2 -C 6 alkyloxyalkyl； X is N or C(R)； and R is hydrogen, halogen, C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, C 1 -C 4 alkoxy, C 1 -C 4 haloalkoxy or cyano； or an agrochemically usable salt form thereof； provided that when X is C(R), R 2 cannot be an optionally substituted aryl.
