Compounds of Formula (I), their N-oxides and agriculturally suitable salts are disclosed which are useful as fungicides formula (I), (II) wherein A is a substituted pyridinyl ring; B is a substituted pyridinyl ring; W is C=L or SO.sub.n is O or S; R.sup.1 and R.sup.2 are each independently H; or C.sub.1-C.sub.6 alkyl, C.sub.2-C.sub.6 alkenyl, C.sub.2-C.sub.6 alkynyl or C.sub.3-C.sub.6 cycloalkyl, each optionally substituted; R.sup.3 is H; or C.sub.1-C.sub.6 alkyl, C.sub.2-C.sub.6 alkenyl, C.sub.2-C.sub.6 alkynyl or C.sub.3-C.sub.6 cycloalkyl, C.sub.2-C.sub.6 alkylcarbonyl, C.sub.2-C.sub.6 alkoxycarbonyl, C.sub.2-C.sub.6 alkylaminocarbonyl or C.sub.3-C.sub.8 dialkylaminocarbonyl; R.sup.4 is C1-C6 alkyl, C.sub.2-C.sub.6 alkenyl, C.sub.2-C.sub.6 alkynyl or C.sub.3-C.sub.6 cycloalkyl, each optionally substituted; X is O or S; and n is 1 or 2; provided that when W is C.dbd.O and R.sup.1, R.sup.2 and R.sup.3 are H; then B is other than 4-trifluoromethyl-3-pyridinyl, 2-chloro-4-pyridinyl and 2,6-dihalo-4-pyridinyl. Also disclosed are compositions containing the compounds of Formula (I) and a method for controlling plant diseases caused by fungal plant pathogens that involves applying an effective amount of a compound of Formula (I) ##STR00001##