On June 25 1998, at 1510 central daylight time, a Piper PA-18- 150, N7174B, operated by a private pilot collided with a powerline and the terrain during an aerial application flight over his own property near Fargo, North Dakota. The pilot was seriously injured and the airplane was destroyed. The 14 CFR Part 137 flight was operating in visual meteorological conditions without a flight plan. The flight originated from a private airstrip in Fargo, at 1500 cdt. The pilot reported he loaded the airplane with fungicide at his private airstrip and took off to spray his wheat field one and a half miles away. He reported he was making his first swatch run when the airplane contacted powerlines on the north side of the field. The airplane remained airborne for approximately one quarter of a mile at which time it descended to impact with the terrain. According to an Inspector from the Federal Aviation Administration Fargo, North Dakota Flight Standards District Office the airplane was at an altitude of approximately 20 feet above the ground when it contacted the powerline with the top of the rudder.