Abstract: Insecticidal, ascaracidal and herbicidal bicyclic 3-aryl-pyrrolidine-2,4-dione derivatives of the formula (I) ##STR1## wherein A and Q together represent an alkanediyl, alkenediyl, alkenedienyl or alkenetrienyl group having 3 to 6 carbon atoms, each of these groups being monosubstituted to polysubstituted by identical or different substituents, each of these groups being substituted by halogen, hydroxyl, mercapto, in each case optionally substituted alkyl, alkoxy, alkylthio, cycloalkyl or aryl, and each of these groups additionally being interrupted, if appropriate, by one of the groups below ##STR2## B represents hydrogen or alkyl, X represents alkyl, halogen or alkoxy,Y represents hydrogen, alkyl, halogen, alkoxy or halogenoalkyl,Z represents alkyl, halogen or alkoxy,n represents a number 0, 1, 2 or 3,G represents hydrogen (a) or the groups ##STR3## in which R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6, R.sup.7 and R.sup.8, L, M and E are defined in the specification.