Antimicrobial Activity of Phenolic Extract of Apple Pomace against Paenibacillus larvae and its Toxicity on Apis mellifera

GIMÉNEZ-MARTÍNEZ, PABLO; RAMÍREZ-AMBROSI, MARIA; ALONSO-SALCES ROSA, MARIA; GALLO, BLANCA; BERRUETA LUIS, ANGEL; MAGGI, MATIAS; FUSELLI, SANDRA

Journal of Apicultural Science

Research Institute of Horticulture and Apicultural Research Association

Lugar: Warszawa; Año: 2020 vol. 64 p. 199 - 208

Apis mellifera populations are exposed to different biotic and abiotic stressors that affect bee survival. Paenibacillus larvae, the causative agent of American foulbrood, isone of the most important bacterial pathogens that affect bee health. In some countries,the use of antibiotics is the most common method for the prevention and treatment ofP. larvae infected colonies, however this application can also increase the risk ofoccurrence of resistant strains. An ecological alternative is the use of vegetal extractscontaining bioactive compounds, such as polyphenols. The aim of this study is to checkthe antimicrobial activity of phenolic extracts of apple pomace, from the cider industry,against P. larvae strains by the broth micro dilution method. In addition, the toxicity ofthe phenolic extracts on A. mellifera was verified using the complete exposure method.All extracts contain from 715.31 to 11348.16 μg gal/g DW, determined by Folin-Ciocalteushow antimicrobial activity against P. larvae genotype ERIC I, ranging from 23 μg/mL to150 μg/mL. Toxicity assays of apple pomace extracts on adult bees exhibited a maximummortality of 18% after 48h. This promising alternative will be used in the future toevaluate its toxicity at a field level.