ABSTRACT

This study conducted a comprehensive analysis of the temporal and regional characteristics of fire blight (Erwinia amylovora) and black shoot blight (Erwinia pyrifoliae) outbreaks in Gangwon State from 2021 to 2023. Fire blight was first observed in Wonju, Pyeongchang, and Yeongwol in 2021. The introduction of infected seedlings was identified as a major factor contributing to the spread in Yeongwol, while in Pyeongchang and Wonju, climatic conditions, such as temperature and humidity, were found to significantly promote the outbreaks. In 2022, fire blight occurred in Wonju, Pyeongchang, and Hongcheon, where the first recorded simultaneous occurrence of fire blight and black shoot blight was observed, complicating disease control measures. In 2023, new fire blight cases were reported in Jeongseon and Yanggu, with young trees in Yanggu exhibiting increased susceptibility, leading to concentrated infections. The rapid growth of shoots and flowers facilitated pathogen spread, resulting in a rapid escalation of disease incidence. Black shoot blight was first detected in Wonju and Chuncheon in 2021, with unsanitary use of farm tools identified as the primary factor for disease spread. In 2022, additional cases were reported in Yeongwol and Chuncheon; however, the disease remained confined to isolated orchards, particularly in Chuncheon, where no further spread to surrounding orchards was observed. In 2023, black shoot blight emerged in Hwacheon, where inadequate orchard management and lack of farmer education accelerated the spread of the disease. This study provides crucial information for understanding the occurrence and influencing factors of fire blight outbreaks in Gangwon State. Establishing preventive measures, continuous pattern analysis, and proactive surveillance are essential to mitigate the spread of bacterial diseases in orchards.

Keywords: Black shoot blight, Fire blight, Regional characteristics, Seedling, Simultaneous occurrence