On June 24, 2016, at 1130 eastern daylight time, a Piper PA-28-181, N3024C, was substantially damaged while taxing at the Dutchess County Airport (POU), Poughkeepsie, New York. The flight instructor and student pilot were not injured. Visual meteorological conditions prevailed and no flight plan was filed. The airplane was registered to and operated by West Field Flight Academy, in accordance with 14 Code of Federal Regulations Part 91 as an instructional flight.According to the flight instructor, after landing on runway 6, he contacted the POU air traffic control tower and requested to taxi on the crossing runway to the ramp. They taxied the airplane about 3,000 ft down the runway and just prior to the turn, the airplane started to veer to the left. The flight instructor heard a "metallic sound" left main landing gear collapsed bringing the airplane to a stop. The flight instructor informed the tower controller, performed an engine shut down, and exited the airplane with the student pilot. Examination of the airplane by a Federal Aviation Administration inspector revealed that the left main landing gear strut separated from the wing spar attachment. Further examination revealed the wing spar bent upward. Examination of the landing gear strut revealed that the attaching bolts had sheared in the vicinity of the threads. The fracture features of the bolts displayed signatures consistent with overstress failure.