The distribution of bacteria Gibbsiella quercinecans and Brenneria goodwinii in oak (Quercus robur L.) stands in Latvia

Abstract

Acute Oak Decline (AOD) is a complex plant disease affecting species of native oaks, for example, Quercus robur, in Latvia. Typical AOD symptoms are bark cracks with dark exudate. In other European region countries, like the United Kingdom, AOD is associated with bark insects, for example, Agrilus biguttatus. From the results of the forest survey, it can be concluded that in oak forest stands located in Latvia, there is practically no damage by the bark insect A. biguttatus, which may indicate the existence of another AOD spreading vector. In 2019, from one oak, which was positive for AOD in the spring, repeated stem bleed samples were taken in the autumn period, the laboratory analysis results of the repeated samplings were negative. These findings suggest that the activity of bacteria Brenneria goodwinii and Gibbsiella quercinecans are influenced by climatic conditions.