On May 4, 1998, at 1855 central daylight time, a Grumman G-164B agricultural airplane, N48484, was substantially damaged after impacting trees and terrain following the loss of engine power while maneuvering near Lewisville, Arkansas. The non-instrument rated commercial pilot, sole occupant of the airplane, was not injured. The airplane was owned and operated by Thrash Air Service Inc., of Pelahatchie, Mississippi. Visual meteorological conditions prevailed for the aerial application flight for which a flight plan was not filed. The flight departed from Clinton, Arkansas, at approximately 1835. According to local law enforcement officers that responded to the accident site, the pilot reported that the engine loss power while applying fertilizer to pine trees. The pilot added that there were no open areas available for the forced landing and the airplane settled into the pine trees. Examination of the wreckage by the FAA inspector revealed that both main landing gears were torn off the airframe and the leading edges of both lower wings sustained structural damage. The airplane's fuel system was found to be 3/4 full, and fuel was present in the fuel lines to the engine. The operator reported that 3 other airplanes under his supervision were refueled from the same tanker and none reported any fuel contamination problems. The airplane had been converted to turbine power. The engine was not equipped with an auto re-light or continuos ignition system. The reason for the loss of engine power could not be determined.