Compounds, useful as plant fungicides, having the formula (I): ##STR1## or a stereoisomer thereof, wherein A is CH or N, B is OCH.sub.3 or NHCH.sub.3, X is CH.sub.2, CH.sub.2 O, O or S, Y is R.sup.1 --C.dbd.C--R.sup.2 or R.sup.1 --CH--CH--R.sup.2 wherein R.sup.1 and R.sup.2 are independently H, halo, hydroxy, alkyl, haloalkyl, alkoxy, haloalkoxy, cyano, nitro, amino, mono- or dialkylamino, alkanoylamino, carboxy, alkoxycarbonyl, aminocarbonyl, mono- or di-alkylaminocarbonyl, alkylcarbonyloxy, optionally substituted aryl, optionally substituted aralkyl or optionally substituted aryloxy or R.sup.1 and R.sup.2 join to form with the carbon atoms to which they are attached an optionally substituted benzene ring, and Z is CH.sub.2, CHCH.sub.3, C(CH.sub.3).sub.2 or C.dbd.O.