Hydroxypyridonecarboxamides, their manufacture and use as herbicides

A method of combating the growth of unwanted plants, wherein the unwanted plants and/or their habitat are treated with a herbicidally effective amount of a hydroxypyridonecarboxamide of the formula I ##STR56## where:

• X is oxygen or sulfur;
• R.sup.1, R.sup.2 independently of each other are hydrogen, straight-chain or branched C.sub.1 -C.sub.25 -alkyl, C.sub.3 -C.sub.25 -alkenyl, C.sub.3 -C.sub.25 -alkynyl, C.sub.3 -C.sub.8 -cycloalkyl, C.sub.3 -C.sub.8 -cycloalkyl-C.sub.1 -C.sub.17 -alkyl or C.sub.1 -C.sub.25 -alkoxy, the organic radicals being optionally substituted by halogen, cyano, C.sub.1 -C.sub.5 -alkylcarbonyl, C.sub.1 -C.sub.5 -alkoxycarbonyl, C.sub.1 -C.sub.6 -alkoxy, C.sub.1 -C.sub.6 -haloalkoxy, C.sub.1 -C.sub.6 -alkylthio, C.sub.1 -C.sub.6 -haloalkylthio, or phenyl which in turn is optionally substituted by from one to five halogen atoms and/or from one to three members selected from the group consisting of cyano, nitro, C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -haloalkyl or C.sub.1 -C.sub.4 -haloalkoxy;
• R.sup.3 is hydrogen, C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -haloalkyl, C.sub.1 -C.sub.6 -alkoxy, C.sub.1 -C.sub.6 -haloalkoxy, C.sub.1 -C.sub.6 -alkylthio, C.sub.1 -C.sub.6 -haloalkylthio, halogen or nitro;
• R.sup.4 is C.sub.1 -C.sub.10 -alkyl, C.sub.2 -C.sub.10 -alkenyl, C.sub.2 -C.sub.10 -alkynyl, C.sub.3 -C.sub.10 -cycloalkyl, C.sub.1 -C.sub.10 -alkoxy, C.sub.1 -C.sub.10 -alkylthio, phenyl, the said radicals being optionally substituted by halogen, C.sub.1 -C.sub.3 -alkyl, C.sub.1 -C.sub.3 -haloalkyl, C.sub.1 -C.sub.3 -alkoxy, C.sub.1 -C.sub.3 -haloalkoxy, C.sub.1 -C.sub.3 -haloalkylthio, or phenyl optionally substituted by a member selected from the group consisting of halogen, C.sub.1 -C.sub.3 -alkyl, C.sub.1 -C.sub.3 -alkoxy, C.sub.1 -C.sub.3 -haloalkyl and C.sub.1 -C.sub.3 -haloalkoxy.