Diplodia bulgarica is increasingly becoming recognised as a significant canker causing pest of apple producing regions in Europe, USA and Asia. However, its exact distribution is unknown and is likely more widespread than is currently known. The appears it is mostly associated with organic production systems, stressed or older trees (Eken et al., 2024, Hanifeh et al, 2017; Hinrich-Berger et al., 2021). While it was found to be widespread in surveys of orchards in Iran, pathogenicity trials of recovered isolates were found to be the least aggressive of 4 different canker causing fungi identified on apple orchards in that region (Nourian et al., 2021). 

There are several other similar fungal canker diseases (such as Neonectria spp., previously known as Nectria spp.) present on the island of Ireland which pose a similar threat and are already effectively controlled (McCracken et al., 2003; NIAB, 2025). Therefore, at present it should be considered that properly managed apple orchards with fungicidal tools and good IPM should be able to cope with this pest. However, for organic producers the pest may be more difficult to manage. Awareness of this pathogen should be raised within the Irish apple cultivation sector, but the threat should not be overstated given the options available for control.