Nosema Disease in Honey Bee colonies in Korea
Nosema disease caused by Nosema apis which belongs to fungi is a major cause of honey production loss and is worldwide in distribution. N. apis infects the epithelial cells of the digestive system of adult honeybees. Nosema causes significant losses in population size of honeybee. There are about 25 thousand beekeepers caring for approximately 1,697,000 colonies in Korea. Honey production totaled almost 38,505 metric tons in 2010. This production was estimated to be worth about 274 billion Korean won. To determine infection level of nosema disease during the season, adult worker bees were collected from two colonies of experiment apiary from January to October. Our results indicate that the infection level of nosema disease was increased in spring and autumn. Also we initiated a survey of honeybee colonies on the blooming period of Acacia to determine the prevalence of N. apis. Twenty two hives owned by 18 beekeepers were sampled for this study. Bees were collected on 24th and 25th May of 2012. Nosema spore counts ranged from zero to 5,266,000 spores per bee. The average number of nosema spores per bee was calculated to be 1,375,000. Approximately 86% of the apiaries examined were infected with nosema, based on the presence of spores in the flowering period of Acacia. This indicates that nosema is the predominant species affecting honeybee colonies.