Toxizität von Thymol, Campher, Menthol und Eucalyptol auf Varroa jacobsoni Oud und Apis mellifera L im Labortest

Use of essential oils for the control of Varroa jacobsoni Oud. in honey bee colonies

“…]. Also, the concentration of menthol and eucalyptol in the hive [50] was much lower than necessary for good mite toxicity [49], while the thymol hive concentration measured has caused 100 % mite toxicity in laboratory trials (see section 3.1). Thus, we can assume that thymol is the active ingredient of this formulation.…”

“…The efficacy of camphor was 71.9 %. The results of the laboratory trials of Imdorf et al [49] showed that menthol and camphor caused a high mite mortality at concentrations which were not toxic for bees. Thus, further trials to develop the optimal application mode are necessary to clarify whether this substance can successfully be used for mite control.…”

“…Menthol, another substance with a varroacidal activity [49], has been used for control of A. woodi in North America. After a 3-week treatment, a maximum of 18 mg·kg -1 ) in honey and 2 790 mg·kg -1 ) in wax were detected [56].…”

Organic acids and thymol: unsuitable for alternative control of Aethina tumida (Coleoptera: Nitidulidae)?

“…Air samples were taken (Leichnitz 1985) after 6, 24, 48, and 72 h using an identical experimental setup (Imdorf 2005) but without any SHBs. They were analysed with a gas chromatograph using standard procedures (Imdorf et al 1995).…”

“…None of the concentrations of thymol showed any effect on SHB mortality of the tested life stages. According to previous laboratory experiments (Imdorf et al 1995), the thymol concentration for an effective control of V. destructor should be between 5 and 15 μg per litre of air. In our laboratory experiments, this amount was achieved with the highest dosage of 50 mg after 72 h. In V. destructor treatments, the essential oil is usually applied in long-term treatments of 2 to 4 weeks (Imdorf et al 1999;Floris et al 2004).…”