Triazole compounds of the formula I
wherein
X is -0- or -S-;
Ar is phenyl or phenyl substituted with 1 or 2 groups independently selected from halo, trifluoromethyl, C1-C3 alkyl, C,-C3 alkoxy, difluromethoxy, trifluoromethoxy, pentafluoroethoxy, and 1,1,2,2-tetrafluoroethoxy;
R1 is C1-C4 primary or secondary alkyl;
R2 is hydroxy, C1-C4 alkoxy, benzyloxy, phenoxy, or -NR4R5;
R3 is hydrogen or C1-C4 primary or secondary alkyl;
R4 and R5 independently are hydrogen, C3-C6 cycloalkyl or C1-C3 alkyl, or R4 and R5 combine with the nitrogen atom to which they are attached to form morpholino, pyrrolidino or piperidino; and phytologically-acceptable salts thereof are plant growth regulators.