The invention relates to novel substituted phenyluracils of the general formula (I) in which A represents alkanediyl or alkenediyl, each of which has 2 to 5 carbon atoms and each of which is optionally substituted by cyano, halogen or by in each case optionally halogen- or C1-C4-alkoxy-substituted C1-C4-alkyl, C1-C4-alk-oxy-carbonyl or C2-C4-alkenyl or interrupted by O (oxygen), or represents cyclohexane-1,2-diyl or 1,2-phenylene, Q1 represents O (oxygen) or S (sulphur), Q2 represents O (oxygen) or S (sulphur), R1 represents hydrogen, amino or optionally cyano-, halogen- or C1-C4-alkoxy-substituted alkyl having 1 to 4 carbon atoms, R2 represents optionally halogen-substituted alkyl having 1 to 4 carbon atoms, R3 represents hydrogen, halogen or optionally halogen-substituted alkyl having 1 to 4 carbon atoms, R4 represents hydrogen, cyano, carbamoyl, thiocarbamoyl or halogen, R5 represents cyano, carbamoyl, thiocarbamoyl or in each case optionally halogen-substituted alkyl or alkoxy having in each case 1 to 4 carbon atoms, and R6 represents hydrogen or alkyl having 1 to 4 carbon atoms, and to a process for their preparation and to their use as herbicides.