Cyclohexenone compounds of the formula I ##STR1## where the substituents have the following meanings: R.sup.1 is C.sub.3 -C.sub.4 -alkenyl, C.sub.3 -C.sub.4 -alkynyl, C.sub.2 -C.sub.4 -haloalkyl, C.sub.2 -C.sub.4 -haloalkenyl, C.sub.2 -C.sub.4 -alkoxyalkyl or a radical CH.sub.2 --R.sup.3, whereR.sup.3 is a 5 ring heterocycle with one to three nitrogen atoms and/or one to two oxygen atoms and/or one sulfur atom as hetero-atoms, which may bear up to two double bonds and one or two of the following substituents: C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkylthio, halogen, trifluoromethyl, C.sub.1 -C.sub.4 -alkoxymethyl, C.sub.1 -C.sub.4 -alkylthiomethyl and/or vinyl, or phenyl which may bear one to three of the following groups: C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkylthio, halogen, trifluoromethyl, nitro and/or C.sub.1 -C.sub.4 -dialkylamino, andR.sup.2 is C.sub.1 -C.sub.4 -alkyl,and their agriculturally acceptable salts, processes for their manufacture, and their use.