Leaf-cutter ants (Atta spp. and Acromyrmex spp.) use fresh vegetation to cultivate the fungusthey eat, and consequently can have an economic impact on the agroforestry system as theymay cut and utilize various species that humans cultivate. In forestry, leaf-cutter ants are themost significant pest in pine and eucalyptus plantations because of the damage they cause andtheir broad range. Forest companies have created teams specifically to address this problem,principally through granulated ant baits. The most common insecticides used to control leaf-cutter ants are fipronil and sulfluramid. These compounds remain in the environment for longperiods of time and can pollute soil and bodies of water, and may also be toxic to non-targetspecies. Because there is little data on species of leaf-cutter ants and how to control them, inmost forest plantations in southern Brazil control is standardized and does not consider thespecific characteristics of the region, ant species, or infestation levels. As a result, theobjectives of this project are: to identify the species of leaf-cutter ants that cause the mostdamage, determine the critical density of nests for the most important species, reduce thequantity of granulated baits to the minimum necessary amount, estimate damage levels, anddevelop alternatives for controlling leaf-cutter ants. Field experiments were installed in pineand eucalyptus plantations in nine locations in southern Brazil. The findings from this projectwill provide data on bioecology and the behavior of leaf-cutter ant species in pine andeucalyptus plantations in the region, as well as how to reduce losses by using control measuresbased on ecological principles. They will also make it possible to develop strategies foradequate management of leaf-cutter ant species in pine and eucalyptus plantations,encouraging sustainability in these forest populations and leading to savings on labor, inputs,and silviculture practices while also preserving the environment.