posted 11 years ago
Essential oils have been researched for about two decades as a means of controlling Varroa mites. The one most effective and most commonly used in the commercially available preparations is thymol, which is a prime component of essential oil of thyme. However, we cannot escape from the fact it is an insecticide and a disinfectant. Why otherwise would thyme plants go to the trouble of synthesising it at some considerable metabolic cost?
As an insecticide it harms bees and brood. As a disinfectant it upsets the colony's natural microbiota. It works only through the tolerable differential between the harm it does to bees and the harm it does to mites.
I do not treat any of my colonies for Varroa. I stopped treating my frame colonies after 1 January 2009. I never treated my Warré colonies, the oldest of which has seen 6 winters without artificial requeening.
By not treating, I accept higher losses. My average year-on-year losses are 24%.