The present invention relates to novel effective alkynyl-substituted 3-phenylpyrrolidine-2,4-diones according to the general formula (I) or agrochemically acceptable salts thereof,whereX=C1-C4-alkyl, C1-C4-haloalkyl or C3-C6-cycloalkyl, Y=C1-C4-alkyl or C3-C6-cycloalkyl, R1=hydrogen, C1-C6-alkyl, or C3-C6-cycloalkyl, R2=hydrogen or methyl, R3=C1-C6-alkyl or C1-C6-alkoxy-C2-C6-alkyl, G=hydrogen, a cleavable group L or a cation E, where R3 is not equal to methyl if R1=methyl and R3 is not equal to C1-C3-alkyl if R1=H.The invention also relates to a herbicidal composition comprising a compound of the general formula (I) and to the use of the compounds according to the invention for controlling weeds and weed grasses in crops of useful plants.
