**5. Conclusions**

Varroa mite infestations control using CheckMite+ (Bayer, Germany), Apiguard (Vita Europe Ltd.; England), Bayvarol (Bayer, Germany), Thymovar (Andrma BioVet GmbH, Germany), and ApiLife Var (Chemicals Laif SPA; Vigonza, Italy) at five di fferent EAs in Croatia during the beekeeping season of 2014 induced a higher mite mortality compared to control, as well as in comparison with mite drop in the pretreatment period. Despite unfavourable weather and environmental conditions, with the exceptions of EA5/EA5 and EA1, the relative varroacidal e fficacy of authorized VMP treatments in moderately infested colonies ensured normal overwintering and colony development during the next spring. Due to a lower e fficacy of thymol-based VMPs observed at all EAs in this study conditions, it may be concluded that their use is limited under di fferent treatment regimes. The results of this study imply that e fficacy of used varroacidals strongly depends on geography, but also on timely manner, and can vary from season to season.

It can be concluded that an adequate *V. destructor* mite control must include a few measures, primarily good beekeeping maintenance techniques in combination with appropriate use of authorized VMPs. Di fferent treatment regimes should also be applied with continuous parasitic mite mortality monitoring. Application of varroacides should be performed after the main honey flow, on all apiaries of the same epizootiology area, and in all honey bee colonies with mite infestations levels above the

economic threshold. The same and appropriate treatment timing will ensure honey bee colonies surviving and prevent reinfestations. In specific situations, it is possible to use emergency treatments and alternate synthetic acaricides with food additives with acaricidal effect in rotation programs in order to decelerate the resistance of varroa mites to multiply used acaricides and to reduce the impact of increasing comb wax contamination. All varroacidal treatments must be performed in accordance and in combination with other specific regulations ordered by the national authorities.

**Author Contributions:** Conceptualization, I.T.G.; methodology, I.T.G.; formal analysis I.T.G. and L.S.; investigation, I.T.G., L.S., D.B., and T.Ž.; resources, I.T.G. and D.B.; data curation, L.S. and I.T.G.; writing—original draft preparation, I.T.G.; writing—review and editing, L.S., D.B., T.Ž., and I.T.G.; visualization, L.S. and I.T.G. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Project—Impact of diseases epidemiology and environmental factors to the biological-rearing status of honey bee colonies; Croatian National Beekeeping Program 2014.

**Acknowledgments:** The authors would like to thank colleagues Saša Prđun and Josipa Vlaini´c for technical assistance; and beekeepers Dario Dješka, Ranko Anđelini, Ivan Balenovi´c, and Antionio Mravak for technical support and maintenance of the experimental apiaries.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
