Borders concern much more than territorial lines and are constantly being reconfigured according to continual interactions between various agents. Boundaries between countries, species, or individuals often reflect local perspectives, influencing the recognition and control of plant pests. The study of the Moroccan locust (<i>Dociostaurus maroccanus</i>) surge, which occurred in the Iberian Peninsula between 1898 and 1905, allows us to discuss the relevance of considering those different perceptions to understanding the effectiveness of past measures.