NOVELTY - A pyridine derivative, and its N-oxides or salts are new.    USE - A pyridine derivative for a fungicidal composition for controlling plant diseases (claimed).    ADVANTAGE - The derivative is less costly, less toxic, and environmentally safer, thus improving the crop yield efficiency.    DETAILED DESCRIPTION - A pyridine derivative of formula (I), and its N-oxides or salts are new.    R1=halo, CN, OH, NH2, 1-4C alkyl, 2-4C alkenyl, 2-4C alkynyl, 1-4C haloalkyl, 2-4C haloalkenyl, 2-4C haloalkynyl, cyclopropyl, halocyclopropyl, 2-4C alkoxyalkyl, 2-4C alkylthioalkyl, 2-4C alkylsulfinylalkyl, 2-4C alkylsulfonylalkyl, 2-4C alkylcarbonyl, 2-4C alkoxycarbonyl, 1-3C hydroxyalkyl, 1-3C alkoxy, 1-3C haloalkoxy, 1-3C alkylthio, 1-3C haloalkylthio, 1-3C alkylsulfinyl, 1-3C haloalkylsulfinyl, 1-3C alkylsulfonyl, 1-3C haloalkylsulfonyl, 1-3C alkylamino or dialkylamino;    W1, Y1=CH2, O, C(=0), S(=O), NR8 or a direct bond;    R2-R3=Ph (optionally substituted with up to 5 substituents R6), or 3-6-membered heterocyclic ring containing ring members from carbon atoms or up to 4 heteroatoms from up to two O, S or N (optionally substituted with optionally substituted with up to 5 substituents R6 or R6a on nitrogen atom ring member) where the up to 3 carbon atom ring member is selected from C(=0) or C(=S) and the sulfur atom ring member is from S(=O)p(NR9)q;    R4=H, halo, CN, OH, 1-2C alkyl, 1-2C haloalkyl, 2C alkenyl, 2C halo alkenyl or 2C alkynyl;    R5-R6=halo, CN, OH, NH2, NO2, -CHO, 1-6C alkyl, 2-6C alkenyl, 2-6C alkynyl, 1-6C haloalkyl, 2-6C alkylcarbonyl, 2-6C haloalkylcarbonyl, 2-6C alkoxycarbonyl, 2-6C alkylaminocarbonyl, 3-6C dialkylaminocarbonyl, 3-6C alkylaminoalkoxy, 2-6C haloalkenyl, 2-6C haloalkynyl, 3-6C cycloalkyl, 3-6C halocycloalkyl, 4-8C alkylcycloalkyl, 4-8C cycloalkylalkyl, 5-8C alkylcycloalkylalkyl, 2-6C alkoxyalkyl, 2-6C cyanoalkyl, 1-6C hydroxyalkyl, 1-6C alkoxy, 1-6C haloalkoxy, 3-6C cycloalkoxy, 3-6C halocycloalkoxy, 2-6C alkylcarbonyloxy, 1-6C alkylthio, 1-6C haloalkylthio, 1-6C alkylsulfinyl, 1-6C haloalkylsulfinyl, 1-6C alkylsulfonyl, 1-6C haloalkylsulfonyl, 3-9C trialkylsilyl, 2-6C alkylcarbonylthio, 1-6C alkylamino or 2-6C dialkylamino;    R6a=CN, 1-6C alkyl, 2-6 alkenyl, 2-6 alkynyl, 1-6C haloalkyl, 2-6 alkylcarbonyl, 2-6 haloalkylcarbonyl, 2-6 alkoxycarbonyl, 2-6 alkylaminocarbonyl, 3-6C dialkylaminocarbonyl, 2-6 haloalkenyl, 2-6 haloalkynyl, 3-6C cycloalkyl, 3-6C halocycloalkyl, 4-8C alkylcycloalkyl, 4-8C cycloalkylalkyl, 5-8C alkylcycloalkylalkyl, 2-6C alkoxyalkyl, 1-6C alkoxy, 1-6C haloalkoxy, 3-6C cycloalkoxy, 3-6C halocycloalkoxy, 1-6C alkylthio, 1-6C haloalkylthio, 1-6 alkylsulfonyl, 1-6C haloalkylsulfonyl or 3-9C trialkylsilyl;R8-R9=H or 1-3C alkyl;    m=0-5;    n=0-2;and    p, q=0-2.    Provided that when Y1 is a direct bond and R3 is a phenyl ring substituted with two alkoxy substituents attached at the meta positions, then R4 is hydrogen. INDEPENDENT CLAIMS are included for:    (1) a fungicidal composition comprising compound (I), and other fungicide(s) or additional component(s) from surfactants, solid diluents or liquid diluents; and    (2) a method of controlling plant diseases caused by fungal plant pathogens comprising applying compound (I) to the plant, portion(s) of the plant, or to the plant seed.