The invention relates to new 1-H-3-aryl-pyrrolidine-2,4-dione derivatives of the formula (I) ##STR1## in which A and B together with the carbon atom to which they are bonded represent a substituted cycle,X represents alkyl, halogen or alkoxy,Y represents hydrogen, alkyl, halogen, alkoxy or halogenoalkyl,Z represents alkyl, halogen or alkoxy,n represents 0, 1, 2 or 3,G represents hydrogen (a) or the groups ##STR2## represents a metal ion equivalent or an ammonium ion, L and M represents oxygen and/or sulphur,R.sup.1 represents in each case optionally halogen-substituted alkyl, alkenyl, alkoxyalkyl, alkylthioalkyl, polyalkoxyalkyl or cycloalkyl, which can be interrupted by hetero atoms, optionally substituted phenyl, optionally substituted phenylalkyl, substituted hetaryl, substituted phenoxyalkyl or substituted hetaryloxyalkyl,R.sup.2 represents in each case optionally halogen-substituted alkyl, alkenyl, alkoxyalkyl, polyalkoxyalkyl or in each case optionally substituted phenyl or benzyl,R.sup.3, R.sup.4 and R.sup.5 independently of one another represent in each case optionally halogen-substituted alkyl, alkoxy, alkylamino, dialkylamino, alkylthio, alkenylthio, cycloalkylthio and in each case optionally substituted phenyl, phenoxy or phenylthio,R.sup.6 and R.sup.7 independently of one another represent hydrogen, in each case optionally halogen-substituted alkyl, alkenyl, alkoxy, alkoxyalkyl, or represent optionally substituted phenyl, optionally substituted benzyl, or, together with the adjacent N-atom, represent a cycle which is optionally interrupted by oxygen or sulphur,to processes for their preparation, and to their use as pesticides.