Agrometeorological risk of Epitrix papa in Europe under climate change using ERA5-land and EURO-CORDEX projections

The European distribution range of the recently described potentially threatening potato flea beetle Epitrix papa remain unknown. Understanding its potential range and future spread dynamics requires a host-specific thermal niche assessment. We developed an Epitrix Suitability Index (ESI) by combining a potato Host Suitability Index (HSI), proxied by July mean air temperature with, a Climate Suitability Index (CSI),derived from degree-day accumulation between 1 March and30 September (base 8.1 °C, 625 °Cday per generation). Past conditions were reconstructed from ERA5-Land for 1990-2024; whilefuture projections based on CORDEX-CORE (EUR-22) RegCM4 downscaling of three GCMs under RCP2.6 / SSP1-2.6-TYPE LOW FORCING and RCP8.5 / SSP5-8.5-TYPE HIGH FORCING for 2041-2070 and 2071-2099. Present-day patterns reproduce known potato belts and show high model-agreement across Western and Central Europe, with greater spread across complex terrains such as Alps, the Carpathians, and Fennoscandia, as well as at transition zones. Projections indicate a possible northward shift of suitability of the host and pest, with the strongest shift under RCP8.5 / SSP5-8.5-TYPE HIGH FORCING during 2071-2099. This shift is accompanied by an increasing ESI across the British Isles, southern Scandinavia and the Baltic region, while parts of the Mediterranean may become less suitableas a result of heat stress affecting the host plant. The poleward displacement of the "optimal" belt is robust across members, although the magnitude of the change varies substantially, withuncertainty concentrated along mountainous areas. These results identify regions where adaptationefforts are most needed in terms of surveillance and integrated pest management, and provide a transparent, farm-aware framework for mapping emerging pest risks under climate change.