Most Korean beekeepers have moved from south to north of Korea to collect nectar from black locust (Robinia pseudoacacia) flowers for 2 months. This provided a valuable opportunity to sample bees originating from diverse areas in one location. We initiated a survey of honeybee (Apis mellifera) colonies on the blooming period of Acacia to determine the prevalence of Nosema apis and black queen cell virus (BQCV) in 2013. Nosema causes significant losses in population size of honeybees. Sixteenth hives were sampled for this study. Bees were collected on the 4th and 13th of May, 2013. Nosema spore counts ranged from zero to 1,948,333 spores per bee. The average number of nosema spores per bee was calculated to be 450,000. Approximately 94% of the apiaries examined were infected with nosema, based on the presence of spores in the flowering period of Acacia. Also nosema is thought to be associated with black queen cell virus. RT-PCR analysis shows that BQCV infection rate was 100%. This indicates that nosema and BQCV is the predominant species affecting honeybee colonies.

The bumblebee, Bombus terrestris, has played an important role as one of the alternative pollinators. Recently, pathogens and parasites affect the life span and fecundity of their host and been isolated from B. terristris. In order to detect viral infection in the field populations of B. terristris, we collected adults and isolated total RNA for reverse transcriptase-polymerase chain reaction (PCR). The PCR primers specific for several viruses such as deformed wing virus, Israel acute paralysis virus, Kashmir bee virus and black queen cell virus (BQCV) were newly designed and applied to gene amplification for cloning. Only BQCV was successfully amplified and sequenced, which suggests that BQCV may mainly infects the examined field population of B. terristris. To detect of capsid protein gene of BQCV, 4 selected regions were analyzed by primary PCR and 1 region was successfully amplified, which was further analyzed in quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis demonstrated that BQCV was detected at concentrations as low as 0.1ng/μl total RNA. This result suggests that the detection via qRT-PCR can be applied for the rapid and sensitive diagnosis of BQCV infection in the field population as well as risk assessment of B. terristris.