A compound of the general formula (1) ** Formula ** in which Ar is a radical of the formula in which R 'is hydrogen, halogen, C1-4 alkyl, C2-4 alkenyl, C2-4 alkynyl, trialkylsilylethynyl or 3-hydroxy-3-methyl-but-1-in-1- yl, and R "and R" 'are, independently of each other, hydrogen, C1-3 alkyl or halogen, or Ar is a radical of the formula in which R 'is hydrogen, halogen, C1-4 alkyl or C2-4 alkynyl, and R "and R"' are, independently of each other, hydrogen, methyl, ethyl or halogen, L is O or S； R 1 is C 1-4 alkyl, C 1-4 haloalkyl or C 3-4 cycloalkyl, or C 1-4 alkoxy, C 1-4 haloalkoxy or C 3-4 cycloalkoxy or C 1-4 alkylthio, C 1-4 alkyl-sulfinyl or C 1-4 alkyl 4-sulfonyl, or haloalkylthio (C1-4), haloalkyl (C1-4) -sulfinyl or haloalkyl (C1-4) -sulfonyl or cycloalkylthio C3-4, cycloalkyl C3-4-sulfinyl or cycloalkyl C3-4-sulfonyl； R 2 is hydrogen, C 1-8 alkyl, C 3-4 cycloalkyl, C 2-8 alkenyl, cyanoalkyl (C 1-4), C 1-4 alkoxy-C 1-4 alkyl, C 1-4 alkoxy- (C 1-4 alkoxy) - (C1-4) alkyl or benzyloxyalkyl (C1-4), in which the phenyl ring of the benzyl moiety is optionally substituted with C1-4 alkoxy； Ra is hydrogen or methyl and Rb is hydrogen, methyl, cyano, ethynyl, methoxymethyl, allyloxymethyl or propargiloxymethyl, Rc and Rd are, independently of each other, hydrogen, C1-4 alkyl, halogen, cyano, hydroxy, C1-4 alkoxy or alkoxycarbonyl C1-4, or Ra together with Rb, or Rc together with Rd can be joined together to form together with the carbon atoms to which a 3- to 6-membered carbocyclic or heterocyclic ring is attached containing a heteroatom selected from sulfur, oxygen, nitrogen and NRO, where RO is hydrogen or optionally substituted C1-4 alkyl, Re is hydrogen or C1-4 alkyl, phenyl, benzyl, thienylmethyl or pyridylmethyl, R3 is hydrogen, optionally substituted C1-6 alkyl, C3-6 cycloalkyl optionally substituted optionally containing a heteroatom selected from oxygen, sulfur or nitrogen, optionally substituted C2-4 alkenyl, optionally substituted C2-6 alkynyl, C1-4 alko
