Prevalence of honey bee pathogens and parasites in South Korea: A five-year surveillance study from 2017 to 2021

Honey bees play an important role in the pollination of crops and wild plants and provide important products to humans. Pathogens and parasites are the main factors that threaten beekeeping in South Korea. Therefore, a nationwide detection of 14 honey bee pathogens, including parasites (phorid flies, Nosema ceranae, and Acarapis woodi mites), viruses, bacteria, and fungal pathogens, was conducted from 2017 to 2021 in the country. The infection rate and the trend of detection of each pathogenic agent were determined. A total of 830 honey bee samples from Apis cerana (n = 357) and A. mellifera (n = 473) were examined. N. ceranae (35.53%), deformed wing virus (52.63%), sacbrood virus (SBV) (52.63%), and black queen cell virus (55.26%) were the most prevalent honey bee pathogens, and their prevalence rapidly increased from 2017 to 2021. The prevalence of Paenibacillus larvae, Israeli acute paralysis virus, Ascosphaera apis, A. woodi, Melissococcus plutonius, and chronic bee paralysis virus remained stable during the surveillance period, with infection rates ranging from 5.26% to 16.45% in 2021. Other pathogens, including acute bee paralysis virus, phorid flies, Kashmir bee virus, and Aspergillus flavus, had low infection rates that gradually declined during the detection period. The occurrence of honeybee pathogens peaked in July. SBV was the most common pathogen in A. cerana, whereas N. ceranae was predominant in A. mellifera. This study provides information regarding the current status of honey bee pathogens and presents the trend of the occurrence of each pathogen in South Korea. These data are important for predicting outbreaks of honey bee diseases in the country.