Contribution to the Study of the Antimicrobial Properties of Eucalyptus pauciflora Essential Oil and Evaluation of its Acaricidal Effect on Varroa destructor ofBees

Abstract The antibacterial, antifungal, and acaricidal properties ofEucalyptus pauciflora(Ep) essential oil (EO) from the Constantine region of northeastern Algeria are investigated in this study. The plant’s dry leaves yielded 0.73%. The GC/MS analysis identified 39 compounds, with 1,8-cineole (54.45%) being the most abundant. TheE.pauciflora’s antibacterial activity was tested using the Muller Hinton agar diffusion method onEscherichia coli (E.coli),Staphylococcus aureus (S.aureus), Klebsiella pneumoniae (K. pneumonia)andPseudomonas aeruginosa (P.aeruginosa) at various oil concentrations with DMSO. The diameters of the inhibition zones ranged from 6 mm to 20 mm. The plant’s antifungal power was tested against the tomato fungusFusarium oxysporum (F.oxysporum)by incorporating the product into the Potato Dextrose Agar (PDA) agar medium. The action of EpEO at different concentrations on mycelial growth was compared to determine inhibition rates. The rates of inhibition ranged from 39.27–84.48%. The oil’s acaricidal activity was tested on beehives infested withVarroa destructor. The biological “swaddling” or “cover crop” method was used. The oil has a statistically significant effect (p < 0.05). TheE.paucifloraEO recorded antimicrobial and acaricidal results, indicating that this plant could be used in integrated pest management against the bacteria and fungus tested and theVarroa destructormite.