Abstract
Recent years have witnessed an increase in the mortality of honey bees in many regions of the world. The observed decrease in the bee population results from a combination of factors, and microsporidian parasites Nosema apis and N. ceranae are among the main contributors. Those parasites cause a microsporidian infection that shortens the lifespan of bees and reduces the productivity of bee colonies. The aim of this study was to evaluate the effectiveness of Nozevit, Api Herb and ApiX (acetylsalicylic acid + Artemisia absinthium L. extract) in the control of infections caused by Nosema spp. in a field experiment. Two groups of worker bees were evaluated - hive bees and forager bees returning to the hive. The effect of the analyzed therapies on the number of spores and the microsporidia species were analyzed by the hemocytometric method and duplex PCR. A statistical analysis revealed that the applied treatments had reduced the number of spores by 31.15% on average. In hive bees, Nosema spp. infection was most effectively reduced by Nozevit (67.85%) and ApiX (63.36%). Coinfections (N. ceranae and N. apis) were affirmed in all bee samples before treatments. However, after the treatments, single infection of N. apis and N. ceranae were detected. The tested treatments were more effective in the control of N. apis than N. ceranae.