NOVELTY - Triphenyl-substituted pyridone compound (I), and its N-oxide or salt is new.    USE - In fungicidal composition; and for controlling plant diseases caused by fungal plant pathogens (claimed). Also useful in controlling a broad spectrum of plant diseases, particularly foliar pathogens of ornamental, turf, vegetable, field, cereal, and fruit crops. The pathogens include: Oomycetes including Phytophthora diseases such as Phytophthora infestans, Pythium diseases such as Pythium aphanidermatum; Ascomycetes including Alternaria diseases such as Alternaria solani and Alternaria brassicae.    ADVANTAGE - The compounds (I) are more effective, less costly, less toxic, environmentally safer or have different sites of action.    DETAILED DESCRIPTION - Triphenyl-substituted pyridone compound of formula (I), and its N-oxide or salt is new.    R1=halo, cyano, hydroxy, amino, nitro, -CHO, 1-6C alkyl, 2-6C alkenyl, 2-6C alkynyl, 1-6C haloalkyl, 2-6C haloalkenyl, 2-6C haloalkynyl, 3-6C cycloalkyl, 3-6C halocycloalkyl, 4-8C alkylcycloalkyl, 4-8C cycloalkylalkyl, 5-8C alkylcycloalkylalkyl, 3-6C cycloalkenyl, 2-6C alkoxyalkyl, 2-6C alkylthioalkyl, 2-6C alkylsulfinylalkyl, 2-6C alkylsulfonylalkyl, 2-6C alkylaminoalkyl, 3-6C dialkylaminoalkyl, 2-6C alkylcarbonyl, 2-6C haloalkylcarbonyl, 2-6C alkoxycarbonyl, 2-6C alkylaminocarbonyl, 3-8C dialkylaminocarbonyl, 2-6C cyanoalkyl, 1-6C hydroxyalkyl, 1-6C alkoxy, 1-6C haloalkoxy, 3-6C cycloalkoxy, 3-6C halocycloalkoxy, 2-6C alkoxyalkoxy, 3-6C alkoxycarbonylalkyl, 1-6C alkylthio, 1-6C haloalkylthio, 1-6C alkylsulfinyl, 1-6C haloalkylsulfinyl, 1-6C alkylsulfonyl, 1-6C haloalkylsulfonyl, 3-9C trialkylsilyl, 1-6C alkylamino, 2-6C dialkylamino, 2-6C haloalkylamino, 2-6C halodialkylamino, 2-6C alkylcarbonylamino, 2-6C haloalkylcarbonylamino, 1-6C alkylsulfonylamino or 1-6C haloalkylsulfonylamino;    R2=F or Cl;    R3=halo or methoxy;    R4=H or halo;    n=0-5.    An INDEPENDENT CLAIM is included for a fungicidal composition comprising the compound (I), and at least one other fungicide; or the compound (I), and at least one additional component selected from surfactant, solid diluent and liquid diluent.