Abstract

Global trade has facilitated invasive species introductions, both intentional and accidental, with soil translocation emerging as a key vector. This study focuses on the potential spread of Melanoplus differentialis (M. differentialis), an invasive North American grasshopper first detected in Ulsan, South Korea, in 2018. By 2020 it was designated an ecosystem-disturbing species, prompting habitat monitoring. In 2024, concerns arose that soil relocation during construction at a high-density outbreak site (Onsan Industrial Park) could inadvertently spread M. differentialis to the Seongam Municipal Landfill (Ulsan), where construction debris was moved. Surveys conducted at the landfill in May and September 2025 found no M. differentialis, only native grasshopper species. This absence may be due to egg masses being destroyed during construction or insufficient time for a population to establish after introduction. The findings underscore the importance of continued monitoring at translocation sites, as invasive grasshopper populations can proliferate rapidly even from low-level introductions. The results highlight the effectiveness of Early Detection and Rapid Response (EDRR) efforts in preventing the spread of M. differentialis beyond its initial habitat. Collaboration between the National Institute of Ecology, local government, and private sectors has successfully contained the species within its original site. This study underscores the need for vigilance and coordinated action in managing invasive species, especially those spread through human activities like soil and waste movement.