Institut für nationale und internationale Angelegenheiten der Pflanzengesundheit
Rosaceae, mainly apple (Malus domestica, M. sylvestris) and pear (Pyrus communis) with economically important impact. Infection has also been reported on fruit in the postharvest period. D. bulgarica was first described affecting M. sylvestris in Bulgaria and then M. domestica in Iran. Further reports were from India, Germany, Türkiye, California and recently China. Diplodia bulgarica is not listed as a quarantine pest in Commission Implementing Regulation (EU) 2019/2072. However, according to the pest categorization performed by EFSA (2023), it fulfills the criteria to be regarded as a potential Union quarantine pest for EU. Known geographical distribution of D. bulgarica in EU is restricted to Bulgaria, Germany and Serbia. However, host availability and suitable climate are favourable for its establishment in other EU countries. No further report has been made in Bulgaria. An extensive survey carried out in Germany after the first report identified D. bulgarica as the dominant Diplodia species present and widespread in apple and pear. It is therefore likely that the currently known geographical distribution, at least in EU, may not reflect the reality. In addition to D. bulgarica, several other Diplodia species (e.g. D. intermedia, D. malorum, D. mutila, D. seriata, D. pseudoseriata) and other members of the Botryosphaeriaceae family may also infect apples and pears, even causing similar symptoms (Martino et al., 2024). It is therefore likely that D. bulgarica could be easily overlooked or misidentified based only on symtomatology. Plants for planting, which are the main means of spreading the disease, are traded within EU Member States. Detection of the pathogen at all stages of infection is crucial for the development of an effective strategy to prevent new introductions and further spread of the pathogen. To date, there are no molecular diagnostic tools that can be used for in planta detection and identification of the pathogen. The project aims to reduce the uncertainty about the geographical distribution of D. bulgarica in EU and to develop reliable molecular methods for in planta detection and identification of the fungus, including latent infections.
Federal Ministry of Agriculture, Food and Regional Identity
