On May 5, 2014, about 0900 central daylight time, N7309Z, an Air Tractor 301, was substantially damaged when it made a forced landing to a rice levee in Hessmer, Louisiana, after a loss of engine power. The commercial pilot was not injured. The airplane was registered to and operated by Pro-Air, LLC, Hamburg, Louisiana. Visual meteorological conditions prevailed an no flight plan was filed for the local, aerial spraying flight conducted under 14 Federal Aviation Regulations Part 137. The airplane departed about 0853 from a private airstrip located in Hessmer, Louisiana. The pilot stated that the radial engine lost power (he suspected the blower had failed) as he approached a rice field that he was going to spray and he made a forced landing on a levee. The main landing gear hit a soft spot during the landing and the airplane veered off the road into the field and flipped inverted resulting in substantial damage to the vertical stabilizer and left wing. According to a representative of the airplane recovery company, the three-bladed propeller sustained damage to two of the blades. The engine mounts and firewall were not damaged and there was no obvious damage to the engine. The blower was no accessible to examine. A Federal Aviation Administration (FAA) maintenance inspector reviewed the airplane's maintenance logbooks and found no discrepancies. The insurance company totaled the airplane and no further examination of the engine was performed and the loss of power was undetermined.