Determining the stability of clove oil (eugenol) for use as an acaricide in beeswax

Abstract

Clove (Syzygium aromaticum) oil is primarily a mixture of monoterpenes, allylphenols and its major component is eugenol. A study was conducted to determine the stability and sustainability of clove oil components in beeswax samples under semi-field conditions. Five wooden hives with ten comb foundations of frames were used; none of the hives contained bees. For the assays in the four hives, 50 ml of 1% clove oil was tested using different emulsifiers and modes of application. Tween 80 and paraffin oil emulsifiers were used via both evaporation from cups and the spraying method on each of the separate hives. One hive containing blank beeswax was kept as control. Characterization of clove oil and contamination levels of its components in beeswax on days 1, 2, 5, 7, 14 and 28 were determined via gas chromatography/mass spectrophotometry analysis. Eugenol was detected and identified as the major component; its level in beeswax was determined to be stable for up to three weeks with three of the dispensers, but it was not stable when used with paraffin oil using the cup method application. As a result of these studies, we found that if clove oil is used for honeybee Varroosis with different dispensers, eugenol can be stable for a minimum of two weeks in beeswax. As a result, this period should be considered during treatment of Varroosis and before honey harvesting. Absorption and accumulation of eugenol and other effective volatile essential oils and monoterpenes into beeswax may make honeycombs as a secondary, sustain release source.