Abstract Potato cyst nematodes are among the most economically important pathogens affecting potatoes worldwide, capable of reducing yields by up to 80% if not controlled. These nematodes can remain dormant in soil as cysts for up to 30 years without a suitable host. One group of these nematodes, the pale cyst nematode (Globodera pallida), was detected in the United States in 2006 and is currently quarantined in Bingham and Bonneville Counties, Idaho. Spatial modeling has been done to describe the current infestation and spread of G. pallida in fields where it is present. However, no studies have examined its potential establishment in other potato-growing areas within the state. To address this, we developed a random forest model to predict the daily average soil temperature at a depth of 20 cm using longitude, latitude, elevation and daily mean air temperature from 43 weather stations in Idaho, and the Julian days that covered the potato-growing season of April to September 2024. The model performed well, with an R2 value of 0.98 and a root mean square error of 0.98. We then used a process-based, temperature-driven population dynamics model to estimate the multiplication ratio (i.e., the final population density divided by the initial population density in eggs/gram of soil) of pale cyst nematodes in the following locations: Ashton, Grace, Malta, Parma, Picabo, and Shelley. Our results showed that G. pallida could reproduce in major potato-growing regions in Idaho other than the counties where it is currently contained. Moreover, its reproduction coincided with the potato growing season, during which the bulk of planting occurs from mid-April to mid-May and ends in mid-August to late September. A typical long growing season (~18 weeks) associated with russet potato production, along with a reduced proportion of nematodes requiring diapause, suggests the possibility of completing two generations across all locations. Compared to using actual soil temperatures, we observed overestimation and underestimation at specific planting dates x proportion of obligatory diapause in all locations, underscoring the need for more accurate estimation of soil temperature. Keywords: Pale cyst nematode, Establishment risk , Predictive modelling, Soil temperatureNote: This poster was submitted and presented during the 2025 Annual Meeting of the Society for Risk Analysis last December 7-10, 2025 at Washington D.C., USA.