Compounds of formula (I) wherein Q is a group formula (II), (III); Z is ═N—, formula (IV) or ═C(R
2
)—; n is 0, 1, 2 or 3; R
3
or R
4
are each independently of the other hydrogen, alogen, —CN, C
1
-C
4
alkyl or C
1
-C
4
alkoxyl; or R
3
and R
4
together are C
2
-C
5
alkylene; and the agrochemically acceptable salts and all stereoisomers and tautomers of the compounds of formula (I) are suitable for use as herbicides.