The decline of oak stands is a phenomenon that has been observed since the beginning of the 20^th century in many European countries. It can be caused both with abiotic factors such as drought and fluctuations in groundwater levels, as well as biotic factors such as infestations by insects, fungi and bacteria. Acute Oak Decline (AOD) is an dangerous disease of oak trees which was first observed in the XX century. From the moment the first symptoms were noticed, the disease is able to kill trees in up to 6 years. Two species of bacteria, Brenneria goodwinii and Gibbsiella quercinecans, are considered as one of the infectious agents of AOD. The decline of Quercus robur was reported from a weakened stand from the Chojnów Forest District. Symptomatic exudates were sampled and subjected to laboratory analysis. Using the Real time PCR, bacteria Brenneria goodwinii and Gibbsiella quercinecans were confirmed in two out of seven collected field samples. This report is the first information on the observation of these bacteria in weakened stands with the participation of Quercus robur in Poland.

Keywords: Quercus robur, bacteria, Brenneria goodwinii, Gibbsiella quercinecans, real time PCR, Acute Oak Decline