On May 23, 2007, approximately 1300 central daylight time, a Schweizer SGS 2-33A glider, N65804, sustained substantial damage when the left wing tip collided with high vegetation while being towed for takeoff from the Castroville Municipal Airport (T89), near Castroville Texas. The flight instructor and the student pilot receiving instruction were not injured. Visual meteorological conditions prevailed for the 14 Code of Federal Regulations Part 91 flight. The student pilot, who was occupying the front seat, reported that the glider was resting on the left wing in tall grass before takeoff. During takeoff roll, the gliders' acceleration was affected by the drag inflicted on the left wing by the tall vegetation, causing the glider to veer to the left during takeoff. As the glider continued to veer towards the cornfield, the flight instructor released the glider from the tow rope causing the aircraft to impact a cornfield. The flight instructor, who was in the back seat, reported that the left wing tip of the glider was dragged by high grass on the left side of the taxiway, causing the glider to steer to the left side. The flight instructor pilot elected to release the glider from the tow plane as the aircraft continued to veer into a cornfield. A witness, who observed the mishap from the south taxiway, reported seeing the tow plane initiate the takeoff with the glider in tow. The witness added that he noticed that the left wing of the glider was dragging though the tall vegetation on the side of the runway. He then stated that the glider became airborne but was unable to overcome the inherent drag imposed by the tall vegetation. The glider then released the tow rope and veered left into the cornfield. Local law enforcement officers, who were dispatched to the airport, reported that the glider was found with its tail facing the runway, laying approximately five feet into the cornfield at the south edge of the runway access road. There were no reported injuries and written statements were taken from the parties involved regarding the mishap. A Federal Aviation Administration (FAA) inspector, who traveled to the scene, examined the wreckage. The inspector found that the tow-rope was disconnected on the glider side. A visual inspection of the glider revealed substantial damage to the fuselage frame due to the impact with the tall vegetation. Despite several attempts by the investigator-in-charge, the pilot did not provide the Safety Board with a completed Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2).