Lygodium japonicum presents a moderate phytosanitary risk (including impacts of biodiversity and ecosystem services) for the endangered area within the EPPO region with a high uncertainty. 

However, given this species’ ability to spread via spores, the degree of invasiveness, and the difficulty of control experienced elsewhere, the EWG suggests special consideration be given to preventing its entry (and spread) into the EPPO region. In the current area of distribution, L. japonicum has a high negative impact on biodiversity and ecosystem, services.

The overall likelihood of L. japonicum entering the EPPO region is moderate – based on evidence that the species is intercepted as a contaminant of bonsai plants from China and there is some evidence the species is traded. Since L. japonicum is not yet documented within the PRA, likelihood of entry is mostly dependent on its introduction as an ornamental/landscape feature. If this happens, given the habitats and climate of the PRA area, this could readily be followed by escape and introduction into natural ecosystems, similarly as to its initial establishment in North America and Australia.