Benzylidenepyrazolones of the formula I, where the substituents and the index n have the following meanings: R1 is unsubstituted or substituted C1-C6-alkyl; R2 is unsubstituted or substituted C1-C6-alkyl, unsubstituted or substituted C1-C6-alkoxy, halogen, nitro, cyano; R3 is hydrogen, halogen, nitro, cyano, a group NR5R6, OCOR5, NR5COR6, CO2R5, —COSR5, —CONR5R6, C1-C4-alkoxyiminoalkyl, C1-C6-alkylcarbonyl, unsubstituted or substituted C1-C6-alkyl, unsubstituted or substituted C1-C6-alkoxy, unsubstituted or substituted C1-C6-alkylthio, unsubstituted or substituted C2-C6-alkenyl, unsubstituted or substituted C2-C6-alkynyl, unsubstituted or substituted phenyl, unsubstituted or substituted phenoxy, an unsubstituted or substituted 5- or 6-membered saturated or unsaturated heterocycle which may contain up to 4 nitrogen atoms and/or up to 2 oxygen or sulfur atoms as ring members; R4 is C1-C6-alkyl, C1-C4-haloalkyl; R3 and R4 form an optionally substituted saturated or unsaturated 2- or 3-membered bridge which may contain a sulfur atom which may be oxidized to the sulfoxide or sulfone; R5 is hydrogen or unsubstituted or substituted C1-C6-alkyl; R6 is unsubstituted or substituted C1-C6-alkyl; R7 is hydrogen, C1-C6-alkyl or C1-C4-haloalkyl; n is 0,1 or 2, X is hydrogen, chlorine or bromine; where the compounds claimed may be present both in the trans and in the cis form or as a mixture of these isomers, are described.