Have been feeding thymol in syrup, was unseasonally warm 2 days ago, 28Celuis, had a few bee beards, wondering if this is a side effect

Also saw a study on thymol and Fumidil B, whch after 3 years, nosema spores were really low.

This article not subject to U.S. Copyright. Published 2008 by the Americal Chemical Society.

β-Cyclodextrins as Carriers of Monoterpenes into the Hemolymph of the Honey Bee (Apis mellifera) for Integrated Pest Management

Blaise W. LeBlanc,*† Stephen Boué,‡ Gloria De-Grandi Hoffman,† Thomas Deeby,† Holly McCready,† and Kevin Loeffelmann§

Carl Hayden Bee Research Center, USDA ARS, 2000 East Allen Road, Tucson, Arizona 85719; Southern Regional Research Center, USDA ARS, New Orleans, Louisiana 70179; and Southwest Watershed Research, USDA ARS, 2000 East Allen Road, Tucson, Arizona 85719

Received for review May 22, 2008. Revised manuscript received July 12, 2008. Accepted July 14, 2008. We express gratitude to the National Honey Board (project no. 58-5343-7-472) for funding this project.


The Varroa mite (Varroa destructor) is becoming ubiquitous worldwide and is a serious threat to honey bees. The cultivation of certain food crops are at risk. The most noted acaricides against Varroa mites are tau-fluvaninate and coumaphos, but the mites are showing resistance. Since these insecticides are used in the proximity of honey, it is desirable to use natural alternatives. Monoterpenoids such as thymol and carvacrol, that are constituents of oil of thyme and oil of origanum, show promise as acaricides against the Varroa mite (Varroa destructor), but the delivery of these compounds remains a challenge due to the low water solubility and uncontrolled release into the colony. β-cyclodextrin (β-CD) inclusion complexes of thymol, oil of origanum, and carvacrol were prepared on a preparative scale. Competitive binding was studied by fluorescence spectroscopy by using 6-p-toluidinylnaphthalene-2-sulfonate as a fluorescent probe. The complexes were characterized, and the competitive binding described by 1H and 13C NMR spectroscopy chemical shifts. The toxicity of β-CD and the prepared complexes in enriched sucrose syrup was studied by conducting caged honey bee (Apis mellifera) feeding trials. After the first and second weeks of feeding, hemolymph and gut tissue samples were acquired from the caged bee study. The levels of thymol and carvacrol were quantified by solid-phase microextraction gas chromatography mass spectroscopy, using an optimized procedure we developed. High (mM) levels of thymol and carvacrol were detected in bee tissues without any imposed toxicity to the bees, in an effort to deter Varroa mites from feeding on honey bee hemolymph.

Keywords: Varroa; essential oils; phenolics; thymol; carvacrol; origanum; cyclodextrin; drug delivery.