On September 6, 2012, approximately 1700 central daylight time, a Piper PA-25-235, N7655Z, was substantially damaged during a forced landing near Jasper, Missouri. The commercial pilot was not injured. The airplane was owned and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 137 without a flight plan. Visual meteorological conditions prevailed at the time of the accident. The aerial application flight departed Lamar Municipal Airport (KLLU), Lamar, Missouri, approximately 1630. The pilot reported that while spreading turnip seeds, the engine started to lose power. The pilot elected to perform a precautionary landing to the field. During the precautionary landing, he observed a fence and berm ahead so he added power to go over the fence; however, the engine lost all power. During the forced landing, the airplane hit a fence resulting in damage to the propeller, the left main landing gear, and substantial damage to the left wing spar. The postaccident engine examination revealed that a support bracket in the carburetor air box separated and entered the carburetor. The separated piece blocked the venturi and obstructed the airflow within the engine, resulting in the subsequent loss of engine power. An examination of the remaining engine and airframe systems revealed no anomalies. The last annual inspection was completed on September 3, 2012. According to the Federal Aviation Administration inspector who examine the airplane, this support bracket would not be included in the examination and work conducted for an annual inspection and would require the removal of the carburetor air box.