Gardeners can kill leaf cutter ants using a contact insecticide. Pyrethrum dust, an insecticide produced from chrysanthemum flower heads, is a suitable insecticide for organic gardens. Acephate and carbaryl are synthetic alternatives.
The first step to controlling leaf cutter ants is identifying the areas where they are active. This allows gardeners to target leaf cutters while avoiding harm to harvester ants, which compete with leaf cutters for the same territory and help keep the leaf cutters' numbers down. A plant under an initial attack by leaf cutters has leaves lying beneath it as if they had fallen off. The night after the ants cut down the leaves, they cut them up for transport to their nests. By using a flashlight to observe the ants' activity, gardeners can track them back to their nests' vents.
After identifying the vents and trails, the next step is placing contact insecticide in and around each vent and down the ants' trails so that as many ants as possible come in contact with the insecticide. Stopping up or collapsing the vents is counterproductive as the ants simply dig new ones, often at a distance from the original vents.
The third step is placing a ring of diatomaceous earth 5 feet in diameter and 1 to 2 feet wide around each vent the day after using the insecticide. Gardeners should also spread insecticide and diatomaceous earth around each plant showing signs of ant activity and any other plants of the same kind.