Bark canker disease on walnut in Hungary

A. Végh, G. Borsos, I. Tenorio-Baigorria, G. Bujdosó, F. Izsépi, L. Palkovics
During August 2012, vertical oozing cankers have been observed on trunks and branches of walnut trees (Juglans regia) in the city of Zánka, near Lake Balaton and other parts of Hungary. Cankers were observed on trunks and branches, where brown-to-black exudates staining appeared on the bark mainly in the summer. The causative agent, a bacterium was first reported in California (Wilson et al., 1957), and was also recorded in Iran, Spain, France and several Italian locations from walnut trees. The bacteria were isolated from walnut trees. The pathogens were identified with classical (morphological, biochemical and physiological properties, pathogenicity test), and molecular (16S rRNA) methods. For molecular identification of the pathogen the 16S rDNA amplification was performed from strain Bn-WalnutZa-Hun1 with a universal bacterial primer. The sequence was deposited in NCBI GenBank (Accession No. HF936707) and showed 99% sequence identity with B. nigrifluens strains. To our knowledge, this is the first report of a natural outbreak of bacterial bark canker on walnut in Hungary and presence of the pathogen may seriously influence in local orchards and garden production in the future. This appearance may have serious consequences for the future walnut production in Hungary.
Végh, A., Borsos, G., Tenorio-Baigorria, I., Bujdosó, G., Izsépi, F. and Palkovics, L. (2016). Bark canker disease on walnut in Hungary. Acta Hortic. 1149, 47-52
DOI: 10.17660/ActaHortic.2016.1149.9
bark canker, Brenneria nigrifluens, Juglans regia, walnut