On April 1, 2011, about 1200 Pacific daylight time, a Cessna A188B, N5851G, collided with terrain during an aerial application flight near Palouse, Washington. Dale’s Flying Service was operating the airplane under the provisions of 14 Code of Federal Regulations (CFR) Part 137. The commercial pilot sustained serious injuries; the airplane sustained substantial damage to the wings and fuselage from impact forces. Visual meteorological conditions prevailed, and no flight plan had been filed. The pilot reported that he was on his second pass applying dry fertilizer to a field, which had steeply rising terrain of a ridge line at the end of his run. During the turn out, he indicated that the loss of lift from his right bank and gusty wind conditions carried the airplane toward trees at the edge of the field. The airplane did not have enough power to climb over the trees, and despite the pilot's efforts to maneuver away, the airplane collided with the trees.