Abstract: The invention relates to new barbituric acid derivatives of the general formula ##STR1## wherein R is a substituted or unsubstituted phenyl group or heteroaryl group having 5 or 6 ring atoms, the heteroaryl group comprising one or more hetero atoms selected from the group consisting of N, O and S, and the substituents being selected from the group consisting of halogen, cyano, nitro, formyl, acetyl, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 haloalkyl, C.sub.1 -C.sub.4 alkoxy, C.sub.1 -C.sub.4 haloalkoxy and optionally substituted phenoxy;R.sub.1 is a C.sub.3 -C.sub.5 alkyl group, a C.sub.3 -C.sub.5 alkenyl group, a C.sub.3 -C.sub.5 alkynyl group, a cyclopropyl group or a cyclopropyl(C.sub.1 -C.sub.4)alkyl group, andR.sub.2 is a C.sub.1 -C.sub.4 alkyl group or an amino group;as well as salts and metal complexes of the said compounds.These compounds may be used in compositions for the control of insects, in particular aphids, in agriculture, horticulture and silviculture.