Propolis and its effects on bee diseases and pests: a systematic review

Propolis contains substances with antibacterial, antiviral, antioxidant, and immune-stimulatory action and is used in the defense of the colony against microorganisms and parasites. The present study is a systematic review of the use of propolis in bee health and in prevention against the main bee pathogens. A search was performed in databases from 01/01/2009 to 30/04/2020. After applying the criteria, 23 articles were included in the review that investigated the use of propolis to prevent the ectoparasite Varroa destructor, the microsporidium Nosema ceranae, the bacterium Paenibacillus larvae, and the fungus Ascosphaera apis. Of these, nine manuscripts reported the bactericidal effect of propolis against P. larvae (39.13%), and two of these studies simultaneously investigated the fungus A. apis. In total, eight were conducted in vitro and one in the field. Six articles related propolis to acaricidal effect in combating the parasite V. destructor (26.08%), four of which were in vitro and two field experiments. Five studies related propolis to combat the microsporidium N. ceranae (21.73%), all of which were carried out in vitro. Two articles were found (one in vitro and the other in the field) that generically related the importance of the physicochemical composition of propolis to bee immunology and defense against its main pathogens. One study investigated the fungal effect of propolis on the pathogen A. apis in a field experiment. In conclusion, scientific production on this subject is sparse, warranting further research in the field to examine the effects of propolis on bee health.