On July 7, 2004, at 1110 mountain daylight time, a Schweizer Aircraft Corp. G-164B, N7502Y, registered to and operated by Ken Spray LLC, as a 14 CFR Part 137 aerial application flight, experienced a loss of engine power and subsequently nosed over during the landing roll in a corn field located about five miles south of Wendell, Idaho. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft was substantially damaged and the commercial pilot, the sole occupant, was not injured. The flight originated from a private airstrip near Jerome, Idaho, about 40 minutes prior to the accident. The pilot reported that he had completed fertilizing one field and was proceeding to a second field at about 300 feet above ground level when the engine started running rough. The pilot increased mixture to full rich and checked the magnetos, however, the engine lost all power. The pilot maneuvered the aircraft to a corn field. During the landing roll, the aircraft nosed over and came to rest inverted. During an inspection of the engine by a Federal Aviation Administration Inspector from the Boise, Idaho, Flight Standards District Office, the inspector reported that one of the cylinders displayed a crack around the cylinder head.