CURRENT STATUS OF FIRE BLIGHT CAUSED BY ERWINIA AMYLOVORA AND ACTION FOR ITS MANAGEMENT IN KOREA

Fire blight in apple and pear, caused by Erwinia amylovora, is very problematic worldwide and has recently been spreading toward East Asia from Europe. In 2015, fire blight-like symptoms were found in apple and pear orchards in three cities of Korea. Because bacterial black shoot blight caused by Erwinia pyrifoliae has symptoms that are very similar to those of E. amylovora and was reported in Korea already in 1999, more careful analyses were required for confirmation of the fire blight pathogen. Based on several microbiological characteristics including genetic and biological assays, the disease was finally confirmed as fire blight disease caused by E. amylovora. In 2015, 43 orchards were confirmed to be infected by this pathogen, and 18 orchards were confirmed in 2016. The South Korean government set up a management strategy for this disease in 2015, and recommended removing all trees within a 100 m radius range from an infected plant. Moreover, intensive chemical treatment and monitoring of fire blight have been performed. Probably due to these aggressive management actions, the disease incidence rate could be reduced. For efficient monitoring and early detection of the pathogen, fast and on-site detection methods such as loop-mediated isothermal amplification (LAMP) PCR and AgriStrip (R) kit have been introduced and are currently being used in the field.