The present invention relates to new compositions and methods for the regulation of plant growth, especially for fruit abscission, acceleration of ripening and latex discharge of rubber trees, and to new active substances of the class of .beta.-halogenoethylsilanes.The new active substances in the new composition corresponding to the formula ##STR1## wherein X is chlorine or bromine, A represents a radical --SR.sub.1, --NR.sub.2 R.sub.3, --OR.sub.4, --CH.dbd.CH.sub.2 or --CH.sub.2 --CH.sub.2 --X, B and C each independently represent --CH.sub.3, --CH.dbd.CH.sub.2 or --CH.sub.2 --CH.sub.2 --X, the symbols R.sub.1, R.sub.3 and R.sub.4 representing substituted or unsubstituted alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, phenyl or benzyl radicals, R.sub.2 denoting hydrogen or the same as R.sub.3, whereby R.sub.2 and R.sub.3 together with the adjacent nitrogen atom can also form a saturated or unsaturated ring system, and R.sub.4 can furthermore represent the group --COR.sub.5, whereby R.sub.5 stands for alkyl, alkenyl, alkynyl, halogenoalk(en)yl, substituted or unsubstituted phenylalk(en)yl, alkoxyalkyl, alkoxycarbonylalkyl, benzoylalkyl, cycloalkylalkyl, for substituted or unsubstituted phenyl or for a 5- or 6-membered heterocyclic radical.