The pilot stated that when he returned to land after a spreading operation he noticed a dust devil about half way along the strip. The chief pilot, who was on the ground near the southern end of the strip, also noticed the dust devil, and warned the pilot on the company radio. The pilot circled near the northern end of the strip until the dust devil moved off the strip to the west and into the trees. A normal approach and landing was then made from the north. During the landing roll the pilot noticed that the dust devil had reappeared from the trees, and was moving directly into his landing path. Maximum braking was applied, but the aircraft encountered the dust devil and became uncontrollable in the turbulence. The propeller struck the ground and the aircraft slid sideways to the left for forty metres. During the slide, the left wheel axle bolts sheared and the left wing struck the ground.