Bengal UltraDust Fire Ant Killer is a dust that kills on contact. As fire ant mounds pop up in the yard, a light covering of Bengal is sprinkled on the mound. The killing action starts immediately as the ants come into contact with the dust. Over a period of hours, the dust is spread by the ants through the colony to the queen. Bengal UltraDust Fire Ant Killer requires no watering in and has no odor.