Plant biosecurity activities in the United States fall along a continuum ranging from offshore activities to the management of newly established exotic pests. For each step in the continuum, we examine the roles, responsibilities, and information needs of the Animal and Plant Health Inspection Service and other agencies involved in plant biosecurity. Both costs and information needs increase dramatically as a pest penetrates deeper into the continuum. To help meet these information needs, we propose a cyberinfrastructure for plant biosecurity to link phytosanitary agencies, researchers, and stakeholders, including industry and the public. The cyberinfrastructure should facilitate data collection, data integration, risk analysis, and reporting. We also emphasize the role of private industry in providing critical data for surveillance. We anticipate that this article will provide agricultural stakeholders, including scientists, with a better understanding of the information needs of phytosanitary organizations, and will ultimately lead to a more coordinated biosecurity effort.