Salicylaldehyde derivatives and salicyclic acid derivatives of the formula I ##STR1## where A is an unsubstituted or substituted phenyl radical, an unsubstituted or substituted 5-membered heteroaromatic radical having from 2 to 4 nitrogen atoms or two nitrogen atoms and additionally one sulfur or oxygen atom or an unsubstituted or substituted thienyl, pyridyl, naphthyl, quinolyl, indazolyl or benzotriazolyl radical, X is oxygen or sulfur, and the radicals R.sup.1 and R.sup.4 have the means given in the specification, processes and intermediates for their production, and their use as herbicides and bioregulators.