Undesired plant growth in cultivations of useful plants which are resistant to phospho-herbicides, may be controlled with herbicidal compositions, which contain, in addition to the usual inert formulation assistants, a phospho-herbicide and a synergistic amount of at least one further herbicide selected from the group comprising prosulfuron, primisulfuron, dicamba, pyridate, dimethenamide and its S-enantiomer, metolachlor and its S-enantiomer, fluometuron, propaquizafop, atrazine, clodinafop, norflurazone, ametryn, terbutylazine, simazine, prometryn, NOA-402989, as well as the compounds of formulae (I), (II) and (III).