The fungus Graphium euwallaceae, which already occurs in California, Vietnam, and Australia, was detected in a tropical greenhouse in Brandenburg in early 2025. This is apparently the first detection of the fungus in Europe. It is not yet listed in the annexes to Regulation (EU) 2019/2072 or in the European Plant Protection and Health (EPPO).

Graphium euwallaceae is a fungus associated with ambrosia beetles (Euwallacea sp.) and has so far been found in avocado trees, ash-leaved maple, and evergreen maple, among other trees.

It is assumed that the fungus cannot establish outdoors in Germany due to unsuitable climatic conditions; it is very likely that it can establish outdoors in southern European EU member states.

The fungus can also establish in protected cultivation (tropical greenhouses).

The harmful potential of G. euwallaceae has not yet been sufficiently clarified. The phytosanitary risk for Germany is considered low. For southern EU member states, a phytosanitary risk, for example, for avocado and maple, cannot be ruled out. However, since the fungus is associated with Euwallacea sp. and other fungal symbionts (e.g., Neocosmospora (Fusarium) euwallaceae), it should initially be classified as the fungus N. euwallaceae, which is regulated as a Union quarantine pest, due to the high uncertainty of this assessment. To better assess the risk posed by G. euwallaceae, pathogenicity tests should be conducted.

Based on this risk analysis, there is reason to believe that G. euwallaceae could establish itself in tropical greenhouses in Germany as well as in southern member states and cause significant damage. Measures should therefore be taken to prevent the risk of the introduction and spread of this potential quarantine pest (and its vectors) in accordance with Article 29 of Regulation (EU) 2016/2031. The infestation must therefore be eradicated in principle in accordance with Article 29 of Regulation (EU) 2016/2031. In the present case (occurrence in a tropical greenhouse), it is sufficient to contain the infestation and not to move any infected plants, since the climatic conditions in the areas of origin of the vector Euwallacea sp. and other infested areas are not comparable to those in Brandenburg, and therefore the risk of establishment in the field is currently very low. The removal of all host plants in the tropical greenhouse would therefore be disproportionate. Detection and discovery of the pest must always be reported to the responsible authority, i.e., plant protection services report to the JKI. Private individuals, companies, or other institutions report to the plant protection service of their federal state. Further information can be found at https://pflanzengesundheit.julius-kuehn.de/meldepflicht-fuer-neue-schadorganismen.html