Honey bees are essential pollinators for several economically important crops. In temperate countries, honey bee colonies face multiple threats during the overwintering period, such as food availability, diseases, and confinement. Beekeepers commonly use chemicals to improve colony health during winter, but these products can have a negative impact on bee health and pathogens can develop resistance to them. Thus, there is a need for further development of alternative treatments. The aim of this study was to evaluate the impact of one endogenic bacterium (Bombella apis) and 2 commercial probiotic formulas (Bactocell and Levucell) on colony survival, spring development, and Vairimorpha (formerly Nosema) spp. spore count. Probiotic treatments were given in 1: 1 sugar syrup in October 2017 and April 2018, once a week for 2 wk. One experimental group was given Fumagilin-B, the only product approved in Canada to prevent nosemosis, once in October. The administration of 2 commercial probiotics, Bactocell (Pediococcus acidilactici) and Levucell (Saccharomyces cerevisiae boulardii), led to a significant increase in the number of sealed brood cells in spring. None of the probiotic treatments impacted the honey bee gut load of Vairimorpha spp. spores. The results suggest that beneficial microorganisms can improve spring development and performance of honey bee colonies.
Keywords: Lactobacillaceae; Vairimorpha; beekeeping; overwintering; yeast.
© The Author(s) 2023. Published by Oxford University Press on behalf of Entomological Society of America.