On May 30, 1996, at 1911 central daylight time, a Grumman-Schweizer G-164B, N188TB, was substantially damaged following a loss of control near Bunkie, Louisiana. The commercial pilot, sole occupant of the airplane, was not injured. The airplane was owned and operated by the pilot. The aerial application flight was conducted under Title 14 CFR Part 137. Visual meteorological conditions prevailed for the local flight for which a flight plan was not filed. In the enclosed NTSB Form 6120.1/2, the pilot stated that he was applying herbicides to his rice fields approximately 2 miles from the farm strip he departed from. The pilot added that the airplane "began to quit flying" during the turn to reverse direction to initiate a second swath. He further stated that he "lowered the nose, applied full power and dumped the load;" however, the airplane "failed to respond" and continued to descent toward the ground. According to the operator, the pilot recovered to the point that he was able to level the wings prior to impact with the ground. Both main landing gear sank in the soft ground and the airplane nosed over coming to rest in the inverted position. Post-accident examination of the wreckage revealed that both top wings and the forward portion of the fuselage sustained structural damage. The operator further stated that the pitch in one propeller blades was found in the feather position; however, the investigation was not able to determine if this condition was the result of post-impact damage. The density altitude was calculated by the investigator-in-charge to be 1,300 feet at the time of the accident.