Many alien insects, diseases, and weeds threaten our forests. What can be done to stop them? An international team of scientists identified research needed to improve approaches to preventing new pests from arriving and responding when new species invade.

Alien invasive insects, pathogens, and weeds threaten the viability of trees and forests worldwide. Predicting new species and preventing them from arriving, or detecting and rapidly responding to newly discovered invasive species are both cheaper strategies, and more likely to be effective than waiting to respond until new pests are well established. A Northern Research Station scientist led an international team that identified critical, overarching research needs to improve these proactive management strategies. Needs include development of pest risk assessments and maps for species that are not yet in the United States as well as the pathways that might bring them to the nation, which are essential for prediction and prevention efforts. Risk assessments would improve with greater access to information about pests associated with pathways, about the distribution of these pests within their native range, and about the ecology of these pests in other countries that have been invaded. Responses to nonnative species, such as phytosanitary measures including fumigation of wood containers, reduce the risk of unintentional pest introductions. Tradeoffs likely exist between general prevention tactics that exclude many, but not all, invasive pests and specialized tactics that target high-risk pests. New approaches to comparing the aggregate costs and benefits of these approaches are needed.