Challenges associated with the surveillance of exotic fungal and oomycete pathogens of forest trees under the European quarantine regulation

Key message Despite the strong legal framework provided by the European Union (EU) Plant Health Regulation, its implementation by Member States remains constrained by gaps in biological and epidemiological knowledge, as well as by insufficient information for the reliable diagnosis of several quarantine pathogens. By outlining these challenges, we identify scientific needs and promising avenues for improvement, providing guidance to strengthen early detection, risk-based surveillance, and diagnostic reliability across the EU.