Efficacy of plant-based remedies for Varroa destructor control in honey bee colonies: A preliminary study.

The Western honey bee (Apis mellifera L.) plays a crucial role in global ecosystems and agriculture, yet the ectoparasitic mite Varroa destructor remains a primary cause of severe varroosis and significant colony morbidity and mortality. Current reliance on synthetic acaricides often leads to the development of mite resistance and raises concerns regarding chemical residues in hive products. This has created an urgent need for innovative and effective veterinary strategies for parasite control. This study investigated the efficacy of traditional plant-based remedies as an alternative treatment for V. destructor infestations in honey bee colonies. Herbal decoctions from medicinal plants (e.g., nettle, clove, linden, peppermint, lavender, sage, dandelion), known for their anti-parasitic properties, were applied to bee colonies via aerosol. V. destructor infestation levels were monitored monthly using a non-destructive CO₂-induced narcosis method. Statistical analysis, specifically a Linear Mixed Model (LMM), revealed a significant decrease in mean Varroa infestation from 1.8 % in 2021-1.1 % in 2023 across the experimental colonies (p < 0.000001 for year effect). Furthermore, the LMM confirmed significant differences in efficacy among the tested decoctions (p < 0.000001 for Decoction label effect), with specific extracts (DIII and DV) demonstrating superior performance. These findings highlight a validated, ecologically derived phytotherapeutic approach for Varroa management, demonstrating its potential to significantly reduce mite populations over multiple years without adverse effects on honey bee health. This research provides valuable insights into natural alternatives for parasitic mite control in domesticated animals like honey bees.