Synergistically acting herbicidal mixtures

A synergistic herbicidal mixture comprising

• A) at least one 3-heterocyclyl-substituted benzoyl derivative of the formula I
• in which the variables have the following meanings:
• R1, R3 are halogen, C1-C6-alkyl, C1-C6-haloalkyl, C1-C6-alkoxy, C1-C6-haloalkoxy, C1-C6-alkylthio, C1-C6-alkylsulfinyl or C1-C6-alkylsulfonyl;
• R2 is a heterocyclic radical selected from the group:
• isoxazol-3-yl, isoxazol-4-yl, isoxazol-5-yl, 4,5-dihydroisoxazol-3-yl, 4, 5-dihydroisoxazol-4-yl and 4,5-dihydroisoxazol-5-yl, it being possible for the six radicals mentioned to be unsubstituted or mono- or polysubstituted by halogen, C1-C4-alkyl, C1-C4-alkoxy, C1-C4-haloalkyl, C1-C4-haloalkoxy or C1-C4-alkylthio;
• R4 is hydrogen, halogen or C1-C6-alkyl;
• R5 is C1-C6-alkyl;
• R6 is hydrogen or C1-C6-alkyl;
• or one of its environmentally compatible salts;
• and
• B) two herbicides selected from the group including imazapyr, imazaquin, imazamethabenz-methyl, imazamox, imazapic and imazethapyr;
• or one of its environmentally compatible salts;
• and, if desired,
• C) at least one herbicidal compound from the group of the acetyl-CoA carboxylase inhibitors (ACC), acetolactate synthase inhibitors (ALS), amides, auxin herbicides, auxin transport inhibitors, carotenoid biosynthesis inhibitors, enolpyruvylshikimate 3-phosphate synthase inhibitors (EPSPS), glutamine synthetase inhibitors, lipid biosynthesis inhibitors, mitosis inhibitors, protoporphyrinogen IX oxidase inhibitors, photosynthesis inhibitors, synergists, growth substances, cell wall biosynthesis inhibitors and a variety of other herbicides;
• in a synergistically effective amount.