On January 21, 2007, at 0910 eastern standard time, an Ayers S2R-G6, N3209X registered to and operated by Ag Flying Service, Inc., as a Title 14 CFR Part 137 aerial application flight, collapsed the right main landing gear during a soft field landing at the Wauchula Municipal Airport in Wauchula, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The commercial pilot reported no injuries, and the airplane was substantially damaged. The flight originated from the Wauchula Municipal Airport at about 0830. According to the pilot, during a normal soft field landing the right main gear collapsed about 20 yards into the landing roll and the airplane came to an abrupt stop. The pilot egressed without injury. Examination of the airplane by an FAA Inspector found wrinkling of the metal skin between the front and rear spars on the right wing. Further examination found the right main gear strut fractured and separated near its attachment point to the airframe. The landing gear strut was removed and sent to the NTSB Materials Laboratory for further examination. The examination found that the fractures were on slant planes and had deformation adjacent to the fractures consistent with overstress fracture in bending. Corrosion deposits on the fracture surface were orange in color consistent with post-fracture oxidation. No significant preexisting corrosion was observed.