Abstract: A compound of formula (I): ##STR1## where E is oxygen or sulphur; A is CR.sup.3 or N where R.sup.3 is hydrogen or hydrocarbyl; D completes a 5 or 6-membered non-aromatic heterocyclic ring which optionally contains additional heteroatoms selected from oxygen, nitrogen or sulphur and which is optionally substituted by an optionally substituted lower hydrocarbyl group, or an optionally substituted heteroaryl group; R.sup.1 and R.sup.2 are each independently hydrogen; optionally substituted lower hydrocarbyl, or optionally substituted heteroaryl, or R.sup.1 and R.sup.2 together with the nitrogen atom to which they are attached, form a heterocyclic ring; Z represents halogen optionally substituted lower hydrocarbyl, optionally substituted lower hydocarbyloxy, optionally substituted lower hydrocarbylthio, hydrocarbylsulphinyl or hydrocarbylsulphonyl, cyano, nitro, CHO, NHOH, ONR.sup.7' R.sup.7", SF.sub.5 ; CO (optionally substituted lower hydrocarbyl), acylamino, COOR.sup.7, SO.sub.2 NR.sup.8 R.sup.9, CONR.sup.

Abstract: A synergistic herbicidal composition containing (A) a cyclohexanedione compound of formula (I): ##STR1## wherein n is 0 or 1; and (B) a chloroacetanilide compound of the formula (II): ##STR2## wherein R.sup.1 is hydrogen, methyl or ethyl; R.sup.2 is hydrogen or ethyl; R.sup.3 is hydrogen or methyl; and R.sup.4 is methyl, methoxy, methoxymethyl, ethoxy or butoxy. A method of controlling the growth of undesirable vegetation, particularly in crops, using this synergistic composition is also disclosed.