PHYTO-THREATS: Addressing Threats to UK Forests and Woodlands from Phytophthora; Identifying Risks of Spread in Trade and Methods for Mitigation

The multidisciplinary ‘Phyto-threats’ project was initiated in 2016 to address the increasing risks UK forest and woodland ecosystems from trade-disseminated Phytophthora. A major component of this examine risk Phytophthora spread through nursery trade practices. Close 4000 water root samples were collected plant nurseries located across over a three-year period. Approximately half tested positive for DNA using metabarcoding approach with 63 species identified nurseries, including quarantine-regulated pathogens not previously reported UK. diversity within linked high-risk management practices such as use open rather than closed sources. Analyses global biological traits pathways that explained host range, which may be value horizon-scanning. Phytophthoras having higher oospore wall index faster growth rates had wider ranges, whereas cold-tolerant broader geographic latitudinal ranges. Annual workshops revealed how stakeholder sector ‘appetite’ accreditation increased three years, although an exploratory cost-benefit analysis indicated predicted benefits introducing best practice expected by outweigh their costs only when range pests diseases (for example, Xylella) is considered. However, scenario analyses demonstrated significant potential carbon society introduction new tree-infecting Phytophthora: Thus, overall net benefit adopting could substantial.