Herbicidal triazinones

A compound of the formula ##STR4## wherein:

• R.sup.1 represents C.sub.1 -C.sub.6 alkyl, C.sub.3 -C.sub.6 cycloalkyl, phenyl or phenyl monosubstituted with C.sub.1 -C.sub.3 alkyl, C.sub.1 -C.sub.3 alkoxy, halogen, C.sub.1 -C.sub.3 haloalkyl or C.sub.1 -C.sub.3 haloalkoxy;
• R.sup.2 represents hydrogen, C.sub.1 -C.sub.6 alkyl or C.sub.3 -C.sub.6 cycloalkyl;
• and
• X.sup.1 and X.sup.2 represent hydrogen atoms or combine to form a carbon-carbon bond;
• with the provisos that when R.sup.2 is methyl, R.sup.1 is other than phenyl;
• and when X.sup.1 and X.sup.2 combine to form a carbon-carbon bond and R.sup.2 is ethyl, R.sup.1 is other than phenyl, 4-chlorophenyl and 4-methoxyphenyl.