Background
Agrilus anxius is a quarantine pest in the EU ((EU) 2019/2072)1. It is also listed as a priority pest and thus annual surveys and a contingency plan is required for it ((EU) 2019/1702)2. In survey planning and development of contingency plans for quarantine pests the area of potential establishment is an important factor to take into account.

Agrilus anxius is native in North America and widespread in boreal and northern temperate regions in both USA and Canada (EPPO 2021a,b). In a PRA by EPPO (2011) it is considered that the temperature accumulation required for the development of A. anxius would be at least 250 degree days above the threshold temperature of 10°C. This assumption was based on the climate in the northern limit of the distribution in North America. Where in the EPPO region the threshold temperature accumulation was reached was analysed using monthly average temperature data for the time period 1961-1990. This analysis indicated that the thermal requirements were not met in the north-western parts of Sweden.

Here, more recent temperature data from the last 20 years were used to calculate the degree days above 10°C across Sweden. These maps can be used together with other information to estimate the area of potential establishment of A. anxius in Sweden, e.g. together with the distribution of available hosts and minimum temperature for oviposition (EFSA 2021).