On May 10, 2008, at 1838 Pacific daylight time, a Thrush Aircraft, Inc., S-2R, N8860Q, sustained substantial damage following a forced-landing in a field near Holtville, California. DS Dusters, Inc. was operating the airplane under the provisions of 14 Code of Federal Regulations Part 137. The commercial pilot, the sole occupant, sustained minor injuries. Visual meteorological conditions prevailed and no flight plan was filed. According to the pilot, following his initial spray over the field, he entered a turn and noticed a loss of available power. He scanned his instruments and did not notice any problems. He continued his pass and on the third pass over the field, the loss of power became excessive. He added throttle and the engine responded. Then, the oil temperature rapidly increased and the pilot could not sustain altitude in the airplane. He force-landed the airplane in a field. The engine continued to turn just prior to impact with the ground. During the landing, the engine separated from the airframe and the right wing was crushed. Post accident examination of the Pratt and Whitney 1340 engine showed that it sustained internal thermal damage. The oil tank was full, the oil lines were clear, and manual activation of the oil pump and later visual examination showed no mechanical anomalies.