Losses of Honey Bee Colonies and Risk Factors for their Mortality in Bulgaria During 2020

The study is based on a comparative analysis of the established losses of bee colonies by regions in Bulgaria and on the characterization of the risk factors for available mortality in 2020. Information for different types of forage sources with potential risk for Apis mellifera due to pesticide treatment, was presented and analyzed. By using the international standardized COLOSS questionnaire for 2020, members of the National Bee Breeding Association and independent beekeepers, owners of a total of 64 apiaries (over 6,800 bee colonies), located in all regions in Bulgaria, were surveyed. Beekeepers were asked to answer questions about the number of wintering honey bee colonies and how many of them after the winter: were alive but had unsolvable queen problems; were lost through natural disaster and were dead or reduced to a few hundred bees. The survey data show that the highest mortality was found for the North Central region (19%), and the lowest – for the Northwest (1%) and Southwest (2%) regions. Among the reasons for the loss of bee colonies, the leading one is the mortality of honey bees or their significant reduction in the colonies, which is also related to the negative impact of the applied pesticides in the studied areas. In this aspect, the most serious problems were reported in the North Central and Southeast (7%) regions. The presented and analyzed data should be considered when developing activities to protect the honey bee health status in Bulgaria