Most conventional methods for controlling agricultural pests cause environmental problems. Thus, sustainable pest management methods have been constantly sought and tested in recent years. The waste substrate produced by leaf-cutting ants (referred to as ‘nest refuse’) is reported to be repellent to their own foraging. This substrate is avoided by leaf-cutting ants because it presents chemical and physical warning signs to the ants in addition to possible pathogens. In the present study, we experimentally analyzed whether a liquid formulation prepared with the discarded substrate produced by leafcutting ants of the species Acromyrmex balzani and Atta opaciceps would be repellent to the aphid Lipaphis erysimi. A total of 103 bioassays were carried out in petri dishes of ? = 150 mm, with two leaf discs of Brassica oleracea L. (var. acephala) sprayed with the control solution (water/alcohol 50%) or with the extract of the nest refuse of one of the ant species. Bioassays were compared using binomial analysis. Ant waste extracts from both species were efficient in repelling aphids (P < 0.05). New studies can help fill in the gaps found, such as the identification of substances potentially causing the effect, the duration of the effect, and the dosage and adequate amounts of extract to be applied, as well as other crops to be protected, and other pests to be repelled.