Tex. Elec. Code § 145.032
A candidate may not withdraw from the general election after the 74th day before election day.
Acts 1985, 69th Leg., ch. 211, Sec. 1, eff. Jan. 1, 1986.
Acts 2005, 79th Leg., Ch. 1109 (H.B. 2339), Sec. 7, eff. September 1, 2005.