A heterocyclyltriazolinone of the formula ##STR249## wherein R.sup.1 represents hydrogen, hydroxyl, cyano, amino or straight-chain or branched alkyl having 1 to 6 carbon atoms, which is optionally monosubstituted or polysubstituted by identical or different substituents, wherein the alkyl substituents art halogen, cyano, or alkoxy, alkylthio, alkylamino or dialkylamino each having 1 to 4 carbon atoms in the individual alkyl moieties and each of which is straight-chain or branched, and phenyl which is optionally monosubstituted or polysubstituted by identical or different halogen substituents and/or straight-chain or branched alkyl substituents having 1 to 4 carbon atoms;
- additionally represents alkenyl or alkinyl each having 2 to 6 carbon atoms and each of which is straight-chain or branched, alkoxy, alkylthio, alkylsulphinyl or alkylsulphonyl each having 1 to 6 carbon atoms and each of which is straight-chain or branched, or cycloalkyl having 3 to 8 carbon atoms;
- additionally represents arylalkyl or arylsulphonyl each having 6 to 10 carbon atoms in the aryl moiety and optionally 1 to 6 carbon atoms in the straight-chain or branched alkyl moiety and each of which is optionally monosubstituted or polysubstituted in the aryl moiety by identical or different substituents, wherein the aryl substituents in each case are halogen, cyano, nitro, or alkyl, alkoxy or alkylthio each having 1 to 4 carbon atoms and each of which is straight-chain or branched, halogenoalkyl, halogenoalkoxy or halogenoalkylthio each having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms and each of which is straight-chain or branched, alkoxycarbonyl or alkoximinoalkyl each having 1 to 4 carbon atoms in the individual alkyl moieties and each of which is straight-chain or branched, and phenyl which is optionally monosubstituted or polysubstituted by identical or different halogen substituents and/or straight-chain or branched alkyl substituents having 1 to 4 carbon atoms;
- and additionally represents a radical ##STR250## R.sup.2 represents hydrogen, hydroxyl, mercapto, amino, halogen or straight-chain or branched alkyl having 1 to 6 carbon atoms, which is optionally monosubstituted or polysubstituted by identical or different substituents, wherein the alkyl substituents are halogen, cyano, or alkoxy, alkylthio, alkylamino or dialkylamino each having 1 to 4 carbon atoms in the individual alkyl moieties and each of which is straight-chain or branched, and phenyl which is optionally monosubstituted or polysubstituted by identical or different halogen substituents and/or straight-chain or branched alkyl substituents having 1 to 4 carbon atoms;
- additionally represents alkenyl or alkinyl each having 2 to 6 carbon atoms and each of which is straight-chain or branched, alkoxy, alkylthio, alkylsulphinyl or alkylsulphonyl each having 1 to 6 carbon atoms and each of which is straight-chain or branched, or cycloalkyl having 3 to 8 carbon atoms;
- additionally represents arylalkyl having 6 to 10 carbon atoms in the aryl moiety and 1 to 6 carbon atoms in the straight-chain or branched alkyl moiety which is optionally monosubstituted or polysubstituted in the aryl moiety by identical or different substituents, wherein the aryl substituents are halogen, cyano, nitro, or alkyl, alkoxy or alkylthio each having 1 to 4 carbon atoms and each of which is straight-chain or branched, halogenoalkyl, halogenoalkoxy or halogenoalkylthio each having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms and each of which is straight-chain or branched, alkoxycarbonyl or alkoximinoalkyl each having 1 to 4 carbon atoms in the individual alkyl moieties and each of which is straight-chain or branched, and phenyl which is optionally monosubstituted or polysubstituted by identical or different halogen substituents and/or straight-chain or branched alkyl substituents having 1 to 4 carbon atoms;
- and additionally represents a radical ##STR251## Het represents a heterocycle of the formula ##STR252## which is optionally monosubstituted or polysubstituted by identical or different substituents, wherein the substituents are halogen, hydroxyl, mercapto, amino, cyano, nitro, carbamoyl, or alkyl, alkoxy, alkylthio, alkylsulphinyl, alkylsulphonyl, alkylamino, dialkylamino, alkanoylamino or alkylaminocarbonylamino each having 1 to 8 carbon atoms in the individual alkyl moieties and each of which is straight-chain or branched, alkenyl or alkinyl each having 2 to 6 carbon atoms and each of which is straight-chain or branched, halogenoalkyl, halogenoalkoxy, halogenoalkylthio, halogenoalkylsulphinyl or halogenoalkylsulphonyl each having 1 to 6 carbon atoms and 1 to 13 identical or different halogen atoms and each of which is straight-chain or branched, straight-chain or branched alkoxycarbonyl having 1 to 7 carbon atoms, cycloalkyl having 3 to 8 carbon atoms and aryl, arylalkyl, arylalkylideneamino or arylalkylaminocarbonylamino each having 6 to 10 carbon atoms in the aryl moiety and optionally 1 to 4 carbon atoms in the straight-chain or branched alkyl moiety and each of which is optionally monosubstituted or polysubstituted in the aryl moiety by identical or different halogen substituents and/or straight-chain or branched alkyl and/or alkoxy substituents each having 1 to 4 carbon atoms and/or halogenoalkyl substituents having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms;
- R.sup.3 represents hydrogen or straight-chain or branched alkyl having 1 to 6 carbon atoms, which is optionally monosubstituted or polysubstituted by identical or different substituents, wherein the alkyl substituents are halogen, cyano, or alkoxy, alkylthio, alkylamino or dialkylamino each having 1 to 4 carbon atoms in the individual alkyl moieties and each of which is straight-chain or branched, and phenyl which is optionally monosubstituted or polysubstituted by identical or different halogen substituents and/or straight-chain or branched alkyl substituents having 1 to 4 carbon atoms;
- additionally represents alkenyl or alkinyl each having 2 to 6 carbon atoms and each of which is straight-chain or branched, straight-chain or branched alkoxy having 1 to 6 carbon atoms or cycloalkyl having 3 to 8 carbon atoms and
- R.sup.4 represents straight-chain or branched alkyl having 1 to 6 carbon atoms, which is optionally monosubstituted or polysubstituted by identical or different substituents, wherein the alkyl substituents are halogen, cyano, or alkoxy, alkylthio, alkylamino or dialkylamino each having 1 to 4 carbon atoms in the individual alkyl moieties and each of which is straight-chain or branched, and phenyl which is optionally monosubstituted or polysubstituted by identical or different halogen substituents and/or straight-chain or branched alkyl substituents having 1 to 4 carbon atoms;
- additionally represents alkenyl or alkinyl each having 2 to 6 carbon atoms and each of which is straight-chain or branched, straight-chain or branched alkoxy having 1 to 6 carbon atoms or cycloalkyl having 3 to 8 carbon atoms or
- R.sup.3 and R.sup.4, together with the nitrogen atom to which they are bonded, represent a saturated or unsaturated heterocycle which optionally contains 1 to 3 additional heteroatoms wherein said heteroatoms are nitrogen, oxygen and/or sulphur, and which is optionally monosubstituted or polysubstituted by identical or different substituents, wherein said substituents on the heterocyclyl are halogen, hydroxyl, mercapto, amino, cyano, nitro, carbamoyl, or alkyl, alkoxy, alkylthio, alkylsulphinyl, alkylsulphonyl, alkylamino, dialkylamino, alkanoylamino or alkylaminocarbonylamino each having 1 to 8 carbon atoms in the individual alkyl moieties and each of which is straight-chain or branched, alkenyl or alkinyl each having 2 to 6 carbon atoms and each of which is straight-chain or branched, halogenoalkyl, halogenoalkoxy, halogenoalkylthio, halogenoalkylsulphinyl or halogenoalkylsulphonyl each having 1 to 6 carbon atoms and 1 to 13 identical or different halogen atoms and each of which is straight-chain or branched, straight-chain or branched alkoxycarbonyl having 1 to 7 carbon atoms, cycloalkyl having 3 to 8 carbon atoms and aryl, arylalkyl, arylalkylideneamino or arylalkylaminocarbonylamino each having 6 to 10 carbon atoms in the aryl moiety and optionally 1 to 4 carbon atoms in the straight-chain or branched alkyl moiety and each of which is optionally monosubstituted or polysubstituted in the aryl moiety by identical or different halogen substituents and/or straight-chain or branched alkyl and/or alkoxy substituents each having 1 to 4 carbon atoms and/or halogenoalkyl substituents having 1 to 4 carbon atoms and 1 to 9 identical or different halogen atoms.