NCEAS researchers report in Frontiers in Ecology and the Environment that almost 70 percent of the most damaging non-native forest insects and diseases currently afflicting U.S. forests arrive via imported live plants. Once introduced, some of these imported insects and disease organisms establish, and a fraction become major economic pests. The authors describe several possible means to increase bio-security, including intensified efforts at plant inspection stations, precautionary measures that restrict plants from entering the U.S. until risks have been assessed, expanding post-entry quarantines, developing better advance knowledge about pest insects and pathogens, and developing integrated systems approaches that depend on expanded partnerships between researchers and industry.