First Report of Bacteria Associated With Bleeding Cankers on Oak Trees in Serbia

ABSTRACT The aim of this study was to confirm the presence of bacteria that are partly responsible for the oak dieback phenomenon, known as Acute Oak Decline, in Serbia. Seventeen symptomatic oak trees (both Quercus robur and Quercus cerris ) were sampled in April 2024 and analysed using multiplex real‐time PCR. Brenneria goodwinii was detected in one tree from Morović, whereas Gibbsiella quercinecans was found in two trees from Morović and Progar. This is the first report of these bacteria in Serbia, despite bioclimatic models predicting a low likelihood of their presence in the Balkans. Our results indicate the presence of oak dieback bacteria in areas where they have not yet been reported, highlighting the need for increased research and awareness of bacterial diseases in forest trees.