The invention relates to the use of arylcarbonic acid biphenylamides of formula (I) wherein X is halogen or methyl; n is zero, 1 or 2; Y is cyano, nitro, halogen, C 1 -C 4 -alkyl, C 1 -C 4 -haloalkyl, C 1 -C 4 -alkoxy, C 1 -C 4 -halo-alkoxy, C 1 -C 4 -alkylthio, C 1 -C 4 -haloalkylthio, C 1 -C 4 -alkoxy-iminomethyl or allyloxy- iminomethyl; m is zero to 5; Ar is an aryl radical of the formula IIa, IIb or IIc wherein R 1 is hydrogen, halogen, C 1 -C 4 -alkyl or C 1 -C 4 -haloalkyl, R 2 is C 1 -C 4 -alkyl, R 3 is hydrogen, halogen or methyl, R 4 is hydrogen, halogen or C 1 -C 4 -alkyl, R 5 is C 1 -C 4 -alkyl or C 1 -C 4 -haloalkyl, Z is CH or N and R 6 is halogen, C 1 -C 4 -alkyl or C 1 -C 4 -haloalkyl, for seed treatment for protecting plants after germination from the attack of foliar phytopathogenic fungi and corresponding methods of seed treatment for protecting plants after germination from the attack of foliar phytopathogenic fungi. The invention also relates to seed treatment formulations comprising the arylcarboxylic acid biphenylamides of formula (I), and to seeds treated therewith.