Fire blight of apple, caused by Erwinia amylovora, a new disease in Korea.
In June and July 2015, symptoms typical of fire blight were observed on shoots and leaves of apple (Malus pumila) in two commercial orchards located 67.38 km apart in Anseong and Jecheon cities of Korea. Symptoms including leaf and shoot blight were observed on 313 and 8 trees in orchards of Anseong and Jecheon, respectively. Fifteen bacterial isolates were recovered on trypticase soy agar from leaf and shoot lesions that were surface-sterilized in 70% ethyl alcohol for 20 s. All isolates were gram-negative, rod-shaped, and mucoid. Based on the results of pathogenicity tests, the sequences and phenotypic assays, the isolates were identified as E. amylovora. This is thought to be the first report of fire blight of apple caused by E. amylovora in Korea.