In the 1990s, the Bee Research Centre took part in a screening programme testing the potential effectiveness of over 100 essential oils and essential oil components against the varroa mite. Although sage, hyssop and thyme oils proved interesting, only thymol has been used in acaricide products. Thymol treatments require little effort, and there are a variety of preparations on the market. The advantages and drawbacks of thymol use are listed in the articles "Apilife VAR: A new varroacide with thymol as the main ingredient" and "THYMOVAR for Varroa control".
Saegerman C., Humblet M.-F., Leandri M., Gonzalez G., Heyman P., Sprong H., L’Hostis M., Moutailler S., Bonnet S. I., Haddad N., Boulanger N., Leib S. L., Hoch T., Thiry E., Bournez L., Kerlik J., Velay A., Jore S., Jourdain E., Gilot-Fromont E., Brugger K., Geller J., Studahl M., Knap N., Avšič-Županc T., Růžek D., Zomer T. P., Bødker R., Berger T., Martin-Latil S., De Regge N., Raffetin A., Lacour S. A., Klein M., Lernout T., Quillery E., Hubálek Z., Ruiz-Fons F., Estrada-Peña A., Fravalo P., Kooh P., Etore F., Gossner C. M., Purse B.
First expert elicitation of knowledge on possible drivers of observed increasing human cases of tick-borne encephalitis in Europe.
Tick-borne encephalitis (TBE) is a viral disease endemic in Eurasia. The virus is mainly transmitted to humans via ticks and occasionally via the consumption of unpasteurized milk products. The European Centre for Disease Prevention and Control reported an increase in TBE incidence over the past years in Europe as well as the emergence of the disease in new areas. To better understand this phenomenon, we investigated the drivers of TBE emergence and increase in incidence in humans through an expert knowledge elicitation. We listed 59 possible drivers grouped in eight domains and elicited forty European experts to: (i) allocate a score per driver, (ii) weight this score within each domain, and (iii) weight the different domains and attribute an uncertainty level per domain. An overall weighted score per driver was calculated, and drivers with comparable scores were grouped into three terminal nodes using a regression tree analysis. The drivers with the highest scores were: (i) changes in human behavior/activities; (ii) changes in eating habits or consumer demand; (iii) changes in the landscape; (iv) influence of humidity on the survival and transmission of the pathogen; (v) difficulty to control reservoir(s) and/or vector(s); (vi) influence of temperature on virus survival and transmission; (vii) number of wildlife compartments/groups acting as reservoirs or amplifying hosts; (viii) increase of autochthonous wild mammals; and (ix) number of tick species vectors and their distribution. Our results support researchers in prioritizing studies targeting the most relevant drivers of emergence and increasing TBE incidence.
Although the use of thymol leads to residues in the wax and honey, these are negligible from a toxicological viewpoint. Since about 2008 the use of thymol-based products has been declining in Switzerland, and beekeepers making use of these products have tended to experience greater winter losses than those using e.g. formic acid.