Background: The Norwegian Environment Agency (Miljødirektoratet) and the Norwegian Food Safety Authority (Mattilsynet) tasked the Norwegian Scientific Committee for Food and Environment (Vitenskapskomiteen for mat og miljø, VKM) to provide a scientific opinion identifying which growing media associated with import of live plants pose the greatest risk of introducing non-native species to Norway. VKM was also asked to assess how effective various risk-reducing measures are to prevent such introductions. In this report, we focus on the introduction of plant pests. Trade in plants for planting is a large and complex international business where live plants are grown in some areas and shipped to other areas where they are intended to be planted or replanted. Traded plants are usually shipped with associated growing media. Long-lived plants, like trees and bushes, may be imported to the EU (e.g., from Asia) and traded through different countries for several years of on-growth before being shipped to Norway. Long production cycles, partly in outdoor nurseries, suggest that the import of live plants with soil or other growing media into Norway comes with a high probability of introducing plant pests. Such pests could cause severe harm to Norwegian plant health and impact both agriculture and natural ecosystems. In this scientific opinion, we describe the most used growing media and assess the risks associated with these. We further evaluate what types of plants and which exporting countries are considered to pose the highest risks for introducing plant pests. Finally, we describe different risk reduction options and assess the effectiveness of current Norwegian regulations as a tool to reduce risks. Altogether, this assessment provides a comprehensive overview of the potential risks involved in importing soil and other growing media associated with plants for planting and of possible strategies for mitigating these risks.

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Conclusions: The import of soil and other growing media associated with live plants to Norway comes with a significant risk of pest introduction for all assessed organism groups. To illustrate the risks involved, we conducted express pest risk analyses for a few selected pest species. These species were selected for their potential to survive the importation process and possibly find suitable environments for establishment in Norway. However, it should be noted that the examples make up a small fraction of all possible pests that might be introduced by the import of plants and associated growing media. High import volumes of live plants with soil and other growing media increase the likelihood of introducing soil-borne pests that, if they become established, could negatively affect Norwegian agriculture and natural ecosystems. Potential impacts include reduced crop and timber yield, increased control costs for farmers, increased use of pesticides, and loss of plant biodiversity.