On February, 19, 1999, about 0900 hours Pacific standard time, a Christen A-1, N2UJ, sustained substantial damage when it collided with terrain 20 miles northwest of Battle Mountain, Nevada. The commercial pilot/owner and one observer were not injured. The public-use aircraft was operated under 14 CFR Part 91 on contract to the United States Department of Agriculture for pest control. The aircraft departed Battle Mountain about 0700. Visual meteorological conditions prevailed and no flight plan was filed. The pilot stated that he was contracted by the Department of Agriculture to eradicate coyotes. While patrolling an area of rolling terrain, he sighted a coyote in a gully. He established a racetrack pattern and while rolling out of a left turn, still in a 10-degree bank, he encountered a turbulent dust devil. The wing suddenly dropped and he was unable to recover prior to the wing tip contacting the ground. As the aircraft settled, it slid sideways and tore off the right main landing gear before coming to rest on its nose. The pilot estimated the winds were from the northwest at 5 knots gusting to 10 knots and the elevation was 4,800 feet.