On August 21, 1998, about 2030 Alaska daylight time, an Ayers S2R-1820 airplane, N123GA, sustained substantial damage during landing at a private airstrip about 2 miles northwest of Palmer, Alaska. The airplane was being operated as a visual flight rules (VFR) local area, aerial application flight under Title 14 CFR Part 137 when the accident occurred. The airplane was registered to, and operated by Glenn Air Inc., Palmer. The certificated commercial pilot, the sole occupant, was not injured. Visual meteorological conditions prevailed. The flight originated at the Palmer Municipal Airport, Palmer, about 1900. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC), on August 24, 1998, at 0912, the pilot reported the following: He was applying chemicals on several fields. At the conclusion of the spray run, he was landing at a land owner's airstrip, known as Whittaker Farm Airstrip. The airstrip is about 1,800 feet long, and about 30 feet wide. The airstrip had a high standing crop of barley adjacent to the airstrip. During the landing roll, the right wing spray boom contacted the crop, and the airplane pivoted to the right. The airplane received damage to the left wing leading edge, the aileron, and wing ribs.