The invention describes a compound having the formula (I), wherein X is F, Cl, Br, or I; R1 is CH3, C2H5, C2H4R3, C2H3R3R4, C3H7, C3H6R or C3H5R3R4; R is H, CH3, C2H5, C2H4R3 or C2H3R3R4; and R3 and R4 are, independently, X, OH or NH2 for the treatment of plants, for increasing plant growth.