On May 21, 1999, at 0646 mountain daylight time, a Piper PA-25-260, N8531L, owned and operated by the pilot, was destroyed following an in-flight collision with wires while maneuvering 6 miles north of the Richfield Municipal Airport, Richfield, Utah. The commercial pilot, sole occupant aboard, was not injured. Visual meteorological conditions prevailed for the local area aerial application flight being conducted under Title 14 CFR Part 137. The flight originated from the Richfield airport at 0625. No flight plan had been filed. According to the pilot, he was spraying a field with Furadan (a weed killer). Prior to spraying, he flew over the field to observe any obstacles. He began spraying from west to east and made three passes. On the fourth pass, he caught a power line with the landing gear while pulling up after spraying the field. He stated that he was able to fly for a short time but was unable to adequately control the aircraft, and performed a forced landing in the field. The aircraft impacted the ground, damaging the engine, propeller, and the landing gear. The pilot had two additional accidents within the previous year; the first occurred on May 16, 1998, while performing an aerial application flight in N9754P, a PA-25-260D, and the second was on June 16, 1998, and happened while the pilot was performing a ferry flight in N8531L, the same accident aircraft. Following his latest accident, the pilot verbally agreed to voluntarily surrender his aerial application operating certificate to, and at the request of, the Federal Aviation Administration. As of this writing, the pilot had not yet rendered his certificate.