Substituted 1-methyl-3-phenylpyrazoles and the use thereof as herbicides and for the desiccation or defoliation of plants

A substituted 1-methyl-3-phenylpyrazole of the formula I ##STR22## where the substituents have the following meanings:

• R.sup.1 is C.sub.1 -C.sub.4 -haloalkoxy or C.sub.1 -C.sub.4 -haloalkylthio;
• R.sup.2 is halogen;
• R.sup.3 is fluorine or chlorine;
• R.sup.4 is cyano, C.sub.1 -C.sub.4 -fluoroalkyl, C.sub.2 -C.sub.4 -fluoroalkenyl or --C(R.sup.5)(X-R.sup.6)(Y-R.sup.7), where
• R.sup.5 is hydrogen or C.sub.1 -C.sub.4 -alkyl,
• X and Y independently of one another are oxygen or sulfur and
• R.sup.6 and R.sup.7 independently of one another are C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -haloalkyl, C.sub.3 -C.sub.4 -alkenyl, C.sub.3 -C.sub.4 -haloalkenyl or C.sub.3 -C.sub.4 -alkynyl;
• and to the agriculturally useful acid addition salts of I.