A triazolinone derivative of the formula ##STR209## in which R.sup.1 represents C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkyl substituted by one or more members selected from the group consisting of fluorine, chlorine, bromine, cyano, C.sub.1 -C.sub.4 -alkoxy, C.sub.1 -C.sub.4 -alkylcarbonyl and C.sub.1 -C.sub.4 -alkoxycarbonyl, or represents C.sub.3 -C.sub.6 -alkenyl or C.sub.3 -C.sub.6 -alkinyl, or represents C.sub.3 -C.sub.6 -alkenyl or C.sub.3 -C.sub.6 -alkinyl each of which is substituted by one or more members selected from the group consisting of fluorine, chlorine and bromine, or represents C.sub.3 -C.sub.7 -cycloalkyl or C.sub.4 -C.sub.7 -cycloalkenyl, or represents C.sub.3 -C.sub.7 -cycloalkyl or C.sub.4 -C.sub.7 -cycloalkenyl each of which is substituted by one or more members selected from the group consisting of fluorine, chlorine, bromine and C.sub.1 -C.sub.4 -alkyl, or represents phenyl-C.sub.1 -C.sub.3 -alkyl, or phenyl C.sub.1 -C.sub.3 -alkyl which is substituted by one or more members selected from the group consisting of fluorine, chlorine, bromine, cyano, nitro, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, C.sub.1 -C.sub.4 -alkoxy and C.sub.1 -C.sub.4 -alkoxycarbonyl,
- R.sup.2 represents C.sub.1 -C.sub.6 -alkyl or C.sub.1 -C.sub.6 -alkyl which is substituted by one or more members selected from the group consisting of fluorine, chlorine, bromine, cyano, C.sub.3 -C.sub.6 -cycloalkyl, C.sub.1 -C.sub.4 -alkoxy and C.sub.1 -C.sub.4 -alkoxycarbonyl, or represent C.sub.3 -C.sub.6 -alkenyl or C.sub.3 -C.sub.6 -alkinyl, or represent C.sub.3 -C.sub.6 -alkenyl or C.sub.3 -C.sub.6 -alkinyl each of which is substituted by one or more selected from the group consisting of fluorine, chlorine, and bromine, or represents C.sub.3 -C.sub.6 -cycloalkyl, or C.sub.3 -C.sub.6 -cycloalkyl which is substituted by one or more members selected from the group consisting of fluorine, chlorine, bromine and C.sub.1 -C.sub.4 -alkyl, or represents cyclohexenyl, or represents phenyl-C.sub.1 -C.sub.3 -alkyl, or phenyl-C.sub.1 -C.sub.3 -alkyl which is substituted by one or more members selected from the group consisting of fluorine, chlorine, bromine, cyano, nitro, C.sub.1 -C.sub.4 -alkyl, trifluoromethyl, C.sub.1 -C.sub.4 -alkoxy and C.sub.1 -C.sub.4 -alkoxy-carbonyl, and
- Z represents chlorine, C.sub.1 -C.sub.4 -alkoxy, benzyloxy or phenoxy.