Hydroxypyridonecarboxamides of the formula I ##STR1## where: X is oxygen or sulfur;R.sup.1, R.sup.2 independently of each other are hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl or alkoxy, and these organic radicals are substituted or unsubstituted;R.sup.3 is hydrogen, alkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, haloalkylthio, halogen or nitro;R.sup.4 is alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, alkylthio, phenyl or a 5- or 6-membered heterocyclic, aliphatic or aromatic radical containing from one to three heteroatoms selected from the group consisting of oxygen, sulfur and nitrogen, and these radicals are substituted or unsubstituted;with the exception of 6-methyl-4-hydroxypyrid-2-one-3-carboxamide and 6-methyl-4-hydroxypyrid-2-one-3-carboxylic acid-tert-butylamide.