There are no plants that are safe from leaf cutter ants. Leaf cutter ants attack weeds, grasses and ornamental trees and shrubs. They also attack food crops such as cereal crops, plum and peach trees and berry bushes.
There are no known plants resistant to leaf cutter ants because the ants do not actually eat the leaves of the plants that they damage. Instead, the ants cut a portion of a plant's leaf, take it back to the nest and use it to cultivate a fungus. This fungus is the sole source of food for the ants.
During the growing season, ants primarily feed on herbaceous plants and deciduous trees and shrubs. During the dormant season when these plants do not have live foliage, leaf cutter ants damage most species of southern pine trees. The ants prefer loblolly and shortleaf pine trees, though they will also damage slash and longleaf pine trees. The ants are particularly destructive to agricultural operations that grow pine seedlings for the lumber industry.
The most effective pesticide for controlling leaf cutter ants is methyl bromide. However, the Environmental Protection Agency has classified this chemical as unsafe for the environment, rendering its use illegal. Amdro Ant Block, a product formulated of hydramethylnon, is available to consumers for leaf cutter ant control.