BACKGROUND: Since 2015, fire blight disease caused by Erwinia amylovora has been devastating apple and pear orchards every year. To quickly block the disease spreading, infected apple and pear trees have been buried in soil. However, concern on the possibility of the pathogen survival urgently requires informative data on the buried host plants. Therefore, this study was conducted to investigate the survival of the pathogen from the buried host plants.
METHODS AND RESULTS: Apple trees buried in 42 months ago in a Jecheon site and pear trees buried in 30 months ago in Anseong site were excavated using an excavator. Plant samples were taken from stems and twigs of the excavated trees. The collected 120 samples were checked for rotting and used for bacterial isolation using TSA, R2A, and E. amylovora selection media. The purely isolated bacteria were identified based on colony morphology and 16S rDNA sequences. Wood rotting and decay with off smells and discoloring were observed from the samples. A total of 17 genera and 48 species of bacteria were identified but E. amylovora was not detected.
CONCLUSION: Our investigation suggests that the survival of E. amylovora is not likely possible in the infected hosts which have been buried in soil for at least 30 months. Therefore, the burial control is considered to be safe measure for fire blight disease.