On June 4, 1998, about 1530 central daylight time, an Air Tractor 502, N1502U, registered to a private individual, was substantially damaged during takeoff from an airstrip near Clarksdale, Mississippi. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 CFR Part 137 aerial application flight. The commercial-rated pilot, the sole occupant, was not injured. The flight was originating at the time of the accident. The pilot stated that he became distracted by the loader placing a greater amount into the hopper than the previous loads, and he failed to extend the flaps for takeoff. During the takeoff roll, he noted that the airplane was not becoming airborne where it previously had, but thought this was due to the added load in the hopper. The airplane went off the end of the runway into a bean field, collapsing the right main landing gear. He further stated that there was no preimpact failure or malfunction of the engine or airframe.