The fungus Neonectria neomacrospora is considered the causative pathogen for the complex canker of balsam fir. Mainly due to severe outbreaks of the disease in fir stands in Scandinavia since 2008, the fungus was considered as a new pest. However, previous studies and observations of experts indicated that the fungus has long been established in Europe, and is already widespread in Germany. Subsequent investigations and communication with the Member States confirmed this evaluation. A key factor for the complex disease is a preceding mass infestation with endemic balsam woolly aphids (Adelges piceae). Thus, the increasing occurrence of the disease might have climatic reasons as the balsam woolly aphid benefits from mild winters and precipitation deficits.

Due to its high damage potential for forestry, mainly for the production of Christmas trees, N. neomacrospora presents a high phytosanitary risk for Germany and other EU-Member States.

However, the fungus is already widespread in Germany and in other Member States. Thus, official eradication and containment measures do not seem appropriate. Furthermore, specific control strategies for the forestry sector are lacking. In January 2019, the Standing Committee of the European Commission for Plants, Animals, Food and Feed discussed the risk of N. neomacrospora. Due to the wide distribution of the fungus in the Member States, the Member States agreed that the fungus does not fulfil the criteria as a quarantine pest. 

Thus, N. neomacrospora is not classified as a potential quarantine pest and § 4a of the Plant Inspection Order does not apply. Official control and notification of the pest is not necessary.