The objective of this study is to evaluate the damage caused by Acromyrmex heyeri Forel, 1899 and Acromyrmex lobicornis Emery, 1887 to Pinus taeda L. seedlings during the first two months after replanting. The experiment was conducted in the company Bosques del Plata, located in the province of Corrientes, Argentina. The evaluations were carried out at seven, 14, 21, 36, 50 and 65 days after replanting the seedlings, when the number of dead, alive, non-attacked, alive deneedled, and alive deneedled with cuts/damage to the apical bud by leaf-cutting ants was quantified. The results allow us to conclude that A. heyeri and A. lobicornis are responsible for losses to the order of 20.8% of the seedlings in an initial P. taeda stand at 65 days. The damage caused to seedlings by the two leaf-cutting ant species is constant over time, in which A. lobicornis is more voracious than A. heyeri.
