Emerald ash borer (Coleoptera: Buprestidae): a western perspective of an established invasive pest in a new frontier

Since its initial detection in the United States in 2002, emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), has caused extensive mortality of ash (Fraxinus spp.) primarily across the East and Midwest. More recent detections in Colorado and Oregon mark a westward expansion of EAB into regions that differ markedly in climate and ash distribution from previously infested areas. These differences necessitate a reassessment of surveillance strategies, management tactics, and long-term planning for EAB in the West. Here, we summarize the current distribution of EAB in the West, describe state-level response efforts, and synthesize available information on monitoring, spread dynamics, and management strategies within a western context. We also discuss challenges associated with symptom-based assessment in the West, and emphasize the importance of coordinated regional responses, proactive planning, and sustained public outreach. Together, this synthesis provides a framework to support informed decision-making and adaptive management as EAB continues to expand across the West.