The invention relates to novel 2-acyloxypyrrolin-4-ones of the formula (I) in which A, B, G, W, X, Y and Z have the meaning given above, to a plurality of processes and intermediates for their preparation, and to their use as pesticides and/or herbicides. The invention also relates to selective herbicidal compositions comprising, firstly, the 2-acyloxypyrrolin-4-ones and, secondly, a crop plant compatibility-improving compound.The present invention furthermore relates to the boosting of the action of crop protection compositions comprising, in particular, 2-acyloxypyrrolin-4-ones, through the addition of ammonium salts or phosphonium salts and optionally penetrants, to the corresponding compositions, to processes for producing them and to their application in crop protection as insecticides and/or nematicides and/or acaricides and/or for preventing unwanted plant growth.