In its classification by EFSA, the fungus was assessed as a potential quarantine pest. Furthermore, C. siamense is listed in Implementing Regulation (EU) 2020/1213. This Implementing Regulation regulates the conditions for the import of high-risk plants from third countries to reduce unacceptable risks posed by the import of these plants. A complete risk analysis of C. siamense and a final assessment by the Commission as to whether C. siamense will be included in Regulation (EU) 2019/2072 as a Union quarantine pest are still pending. As long as the introduction of the fungus is classified by the EU as a precautionary measure as an unacceptable risk, C. siamense must be considered a potential quarantine pest. Measures must therefore be taken to prevent the introduction and spread of the pest.