Guest Essay Global hosts and global pathogens: a perspective

Plant species are assailed by a remarkable diversity of pathogens, and these and other pests pose a serious direct risk to collections in botanic gardens as well as a potential source of pathogen escape. The high diversity of species in gardens combined with low population numbers minimises the likelihood of disease spread of specialist pathogens, but importation of novel pathogens is a constant concern. In parallel with natural systems, there is little data on pathogen loads in botanic gardens, on what accession policies minimise these and if such loads are likely to differ by country of origin or plant life form. Nevertheless, commonsense measures such as prohibiting the importation of plants in soil, shifting to seed and in vitro propagation, and inspection and quarantine on receiving and transferring plants should be implemented.This edition of Sibbaldia explores a variety of directions for improving our ability to develop strategies for dealing not just with pathogen threats, but with a more rational approach to pests and to microbial interactions that are a natural part of a plant’s heritage.