On May 14, 1998, approximately 1100 central daylight time, an Ayers SR2-T34 agricultural airplane, N393KW, owned and operated by the pilot, was substantially damaged when it impacted a utility pole while applying chemicals to a field near Dewitt, Arkansas. The commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the Title 14 CFR Part 137 aerial application flight, which originated from a private grass airstrip about 15 minutes prior to the accident. In a telephone interview, the pilot reported to the NTSB investigator-in-charge that he was maneuvering around a utility pole when the left wing tip contacted the base of the pole. He then flew the airplane back to his base of operations. Inspection of the aircraft by a FAA inspector revealed that the outboard 2 1/2 feet of the wing was torn off. The pilot also stated that he had flown over 150 hours in the last 30 days, and 12 hours in the last 24 hours, and about 4 hours on the morning of the accident. He also stated that he was fatigued.