In a proactive effort to identify pest management priorities and lay a foundation for future strategies and increased use of Integrated Pest Management in onions, growers, commodity-group representatives, pest control advisors, university specialists, and other technical experts from the Treasure Valley in Oregon and Idaho formed a work group and assembled this publication. The publication begins with an overview of onion production, followed by a discussion of critical production aspects of this crop, including the basics of IPM in onion production in this region. Each pest is described briefly, with links provided for more information on the biology and life cycle of each pest. The publication includes an analysis of management practices and challenges organized by crop life stage in an effort to assist the reader in understanding whole-season management practices and constraints. Current management practices are presented using a “Prevention, Avoidance, Monitoring, Suppression” (PAMS) framework to place practices within a simple IPM classification and to demonstrate areas where additional tools or practices may be needed.