Lessons from across the pond: Great Britain's attempts to eradicate Ips typographus in the face of unprecedented long distance dispersal

Exotic spruce species underpin forestry in Great Britain, and as such, threats to these trees are taken extremely seriously by both the private and public sectors, with the eight-toothed spruce bark beetle, Ips typographus, being the biggest threat to this industry. Though surveillance efforts starting in the 1950's previously failed to find Ips, the discovery of a breeding population in south-east England in 2018 has led to a colossal shift in our understanding of Ips typographus, including a shift in the long-term biosecurity strategy. The 35km-wide sea between GB and continental Europe was assumed to be a complete barrier to Ips, but years of research has shown that this is not the case and the previous assumed maximum dispersal distance (45km) is a vast underestimate, with 200km+ being possible. With the significant outbreak across Europe continuing, GB has now switched to a long-term strategy to managing and eradicating Ips, with research focussing on the susceptibility of Sitka spruce, long-distance dispersal via wind plume modelling, population genetics and phylogeography, and improving our surveillance and diagnostics. We underestimated Ips and though we are confident in the eradication strategy, we have learned significant lessons over the last five years which we are applying across GB to improve our phytosanitary and border surveillance for other European species. However, the discovery of Pseudips mexicanus (native to southern USA and Mexico) in Ireland with no identified pathway for introduction raises concerning questions about the risk from American bark beetles to Europe.