Pyridyl sulphonyl ureas as herbicides and plant growth regulators

A compound of the formula (I) or its salts ##STR77## in which R.sup.1 is iodine,

• R.sup.2 is H, (C.sub.1 -C.sub.4)alkyl, (C.sub.1 -C.sub.3)haloalkyl, halogen, NO.sub.2, CN, (C.sub.1 -C.sub.3)alkoxy, (C.sub.1 -C.sub.3)haloalkoxy, (C.sub.1 -C.sub.3)alkylthio, (C.sub.1 -C.sub.3) alkoxy-(C.sub.1 -C.sub.3)alkyl, (C.sub.1 -C.sub.3)alkoxycarbonyl, (C.sub.1 -C.sub.3)alkylamino, di[(C.sub.1 -C.sub.3)alkyl]amino, (C.sub.1 -C.sub.3)alkylsulfinyl, (C.sub.1 -C.sub.3)alkylsulfonyl, SO.sub.2 NR.sup.a R.sup.b or C(O)NR.sup.a R.sup.b, R.sup.a and R.sup.b)independently of one another are H, (C.sub.1 -C.sub.3)alkyl, (C.sub.3 -C.sub.4)alkenyl, propargyl, or together are --(CH.sub.2).sub.4 --, --(CH.sub.2).sub.5 -- or CH.sub.2 CH.sub.2 OCH.sub.2 CH.sub.2 --,
• R.sup.3 is H or CH.sub.3,
• n is zero or 1,
• W is O or S,
• A is a radical of the formula ##STR78## X is H, halogen, (C.sub.1 -C.sub.3)alkyl, (C.sub.1 -C.sub.3)alkoxy, where the two last-mentioned radicals are unsubstituted or monosubstituted or polysubstituted by halogen or monosubstituted by (C.sub.1 -C.sub.3)alkoxy,
• Y is H, (C.sub.1 -C.sub.3)alkyl, (C.sub.1 -C.sub.3)alkoxy or (C.sub.1 -C.sub.3)alkylthio, where the above-mentioned alkyl-containing radicals are unsubstituted or monosubstituted or polysubstituted by halogen or monosubstituted or disubstituted by (C.sub.1 -C.sub.3)alkoxy or (C.sub.1 -C.sub.3)alkylthio, or is a radical of the formula NR.sup.8 R.sup.9, (C.sub.1 -C.sub.6)-cycloalkyl, (C.sub.2 -C.sub.4)alkenyl, (C.sub.2 -C.sub.4)alkynyl, (C.sub.3 -C.sub.4)alkenyloxy or (C.sub.3 -C.sub.4)alkynyloxy,
• Z is CH,
• R.sup.8 and R.sup.9 independently of one another are H, (C.sub.1 -C.sub.3)alkyl or (C.sub.3 -C.sub.4)alkenyl,
• X.sup.4 is CH.sub.3, OCH.sub.3, OC.sub.2 H.sub.5, CH.sub.2 OCH.sub.3 or Cl,
• Y.sup.4 CH.sub.3, OCH.sub.3, OC.sub.2 H.sub.5 or Cl.