NOVELTY - Substituted 4-thiazol-2-yl-piperidine derivatives (I) are new.    USE - (I) are useful for controlling plant-pathogenic fungi in farming, gardening, forestry, animal health, material protection, and in domestic and hygiene applications, and for treating seeds, transgenic plants and their seeds (all claimed).    ADVANTAGE - (I) exhibit strong fungicidal effect, good plant tolerance and less toxicity, are environmentally friendly, enhance crop yields, and improve quality of the crop.    DETAILED DESCRIPTION - Substituted 4-thiazol-2-yl-piperidine derivatives of formula (I) and their salts, metal complexes and N-oxides are new.    Y1 = O or S;    R2 = H or halo;    Q = 4,5-dihydroisoxazole-3,5-diyl moieties of formula (IIa), (IIb), (IIc) or (IIe) or isoxazole-3,5-diyl moieties of formula (IId) or (IIf);    x = bond that is directly bonded to thiazole moiety;    y = bond that is directly bonded to L1 or R1;    R5 = H, CN, 1-3C (halo)alkyl;    L1 = direct bond, -CH2-, -(C=O)-, S or O;    R1 = phenyl (substituted by at least one Z4, and further substituted by 2-4 Z4 or Z1) or naphthyl, dihydronaphthalenyl, tetrahydronaphthalenyl, hexahydronaphthalenyl, octahydronaphthalenyl or indenyl (all substituted by at least one Z5, and further substituted by 2-4 Z5 or Z1) or 5-6-membered heteroaryl (optionally benzo-fused, substituted by at least one Z6, and further substituted at C by 2-4 Z1 or Z6 and at N by Z6 or Z2) or 3-8C cycloalkyl or 5-8C cycloalkenyl (both substituted by at least one Z7, and further substituted by 2-4 Z7 or Z1);    Z1 = H, halo, OH, NO2, CN, (halo)alkyl, (halo)alkenyl, (halo)alkynyl, (halo)cycloalkyl, alkoxyalkyl, hydroxyalkyl, (halo)alkoxy, alkylcarbonyl, alkoxycarbonyl, alkyl-cycloalkyl, cycloalkoxy-alkyl, cycloalkylamino, (halo)alkylthio, cycloalkylthio, cycloalkylalkyl, alkylcarbonyloxy, (halo)alkylcarbonylamino, alkyl-carbonylthio, (halo)alkylsulfinyl, (halo)alkylsulfonyl-oxy, alkyl-cycloalkylalkyl, -C(=O)NR3R4, -NR3R4, tri(1-2C alkyl)silyl or -L3Z3;    Z2 = H, halo, OH, NO2, CN, (halo)alkyl, (halo)alkenyl, (halo)alkynyl, (halo)cycloalkyl, alkoxyalkyl, hydroxyalkyl, (halo)alkoxy, alkylcarbonyl, alkoxycarbonyl, alkyl-cycloalkyl, cycloalkoxy-alkyl, cycloalkylamino, (halo)alkylthio, cycloalkylthio, cycloalkylalkyl, alkylcarbonyloxy, (halo)alkylcarbonylamino, alkyl-carbonylthio, (halo)alkylsulfinyl, (halo)alkylsulfonyl-oxy, alkyl-cycloalkylalkyl, -C(=O)NR3R4, -NR3R4, tri(1-2C alkyl)silyl;    Z3 = phenyl, naphthalenyl or 5-6-membered heteroaryl (all substituted at C by 0-3 halo, CN, NO2, OH, NH2, -SH, (halo)alkyl, (halo)alkenyl, (halo)alkynyl, (halo)cycloalkyl, alkoxyalkyl, (halo)alkylcarbonyl, alkoxycarbonyl, (halo)alkoxy, (halo)cycloalkoxy, alkenyloxy, alkynyloxy, alkoxy-alkoxy, alkylamino, dialkylamino, (halo)alkylthio, (halo)alkylsulfinyl, (halo)alkylsulfonyl, trisilyl-alkyl or phenyl, and at N by H, -C(=O)H, (halo)alkyl, (halo)alkenyl, (halo)alkynyl, (halo)cycloalkyl, alkyl-cycloalkyl, cycloalkylalkyl, alkoxyalkyl, (halo)alkylsulfonyl, cycloalkylsulfonyl, phenylsulfonyl, (halo)alkylcarbonyl, (halo)alkoxycarbonyl, cycloalkoxycarbonyl, -C(=O)NR3R4, phenyl or benzyl);    Z4 = SH, C(=O)H, 7-8C (halo)cycloalkyl, cycloalkyl-cycloalkyl, halo-cycloalkylalkyl, (halo)cycloalkenyl, 5-6C alkoxyalkyl, alkoxy-alkoxyalkyl, alkylthioalkyl, alkylsulfinyl-alkyl, alkylsulfonyl-alkyl, dialkylaminoalkyl, (halo)alkylaminoalkyl, cycloalkyl-aminoalkyl, 5-6C alkylcarbonyl, halo-alkylcarbonyl, cycloalkylcarbonyl, cycloalkoxycarbonyl, cycloalkyl-alkoxycarbonyl, cycloalkylaminocarbonyl, haloalkoxyalkyl, 5-6C hydroxyalkyl, 5-6C (halo)alkoxy, (halo)cycloalkoxy, cycloalkyl-alkoxy, (halo)alkenyloxy, (halo)alkynyloxy, alkoxy-alkoxy, halo-alkylcarbonyloxy, cycloalkylcarbonyloxy, alkylcarbonyl-alkoxy, 5-6C (halo)alkylthio, 5-6C (halo)alkylsulfinyl, alkylsulfonyl, 1-4C haloalkylsulfonyl, cycloalkylsulfonyl, tri(3-4C alkyl)silyl or (halo)alkylsulfonylamino;    Z5 = tri(2-4C alkyl)silyl, benzyl, phenyl, SH, 5-6C (halo)alkoxy, 2-6C alkenyloxy, 2-6C alkynyloxy or 5-6C (halo)alkylthio;    Z6 = group (substituted on C by SH, cycloalkyl-cycloalkyl or tri(3-4C alkyl)silyl, and at N by haloalkyl, (halo)alkenyl, (halo)alkynyl, (halo)cycloalkyl, alkyl-cycloalkyl, cycloalkylalkyl, cycloalkyl-cycloalkyl, alkylsulfonyl, C(=O)H, benzyl or phenyl);    Z7 = CN, halo, OH, oxo, 1-4C (halo)alkyl, 1-4C (halo)alkoxy, 1-4C (halo)alkylthio or phenyl;    L3 = direct bond, -CH2-, -C(=O)-, S, O, -C(=O)O-, -C(=O)NH-, -OC(=O)- or -NHC(=O)-; and    R3, R4 = H, alkenyl, alkynyl, (halo)alkyl, cycloalkyl, benzyl or phenyl.    INDEPENDENT CLAIMS are also included for:    (1) substituted thiazolyl-piperidine derivatives of formula (XIII) and their salts, metal complexes and N-oxides;    (2) substituted thiazolyl-piperidine derivatives of formula (II) and their salts, metal complexes and N-oxides;    (3) substituted thiazolyl-piperidine derivatives of formula (III) and their salts, metal complexes and N-oxides; and    (4) (3,5-bis-difluoromethyl-pyrazol-1-yl)-acetyl fluoride and their salts, metal complexes and N-oxides.    W7 = Cl, Br, I, p-toluenesulfonyloxy or methylsulfonyloxy; and    W8 = acetyl, 1-4C alkoxycarbonyl, benzyl or benzyloxycarbonyl.