Abstract The effects of using herbal essential oils as fumigants to control Varroa destructor Anderson ＆ Trueman，and the toxicity of these compounds to honeybees，were assayed under laboratory conditions． The results showed that all the oils tested were，to some extent，toxic to honeybees but anise oil，clove oil and cinnamon oil caused 92. 5% ，54% and 12% mite mortality respectively with no toxicity to bees after 48 h． There were significant differences in toxicity between the three oils and the control (P ＜ 0. 05) ． The acute toxicity of anise oil and clove oil to mites was further evaluated by estimating LD50 values． The LD50 values of anise oil for V． destructor and A． mellifera were 0. 949 μL and 4. 033 μL，respectively，and those of clove oil were 0. 795 μL and 1. 965 μL，respectively． Anise oil had a higher selective ratio after 48h ( LD50 to honeybees /LD50 to mites = 4. 250) ． The chemical composition of anise oil and clove oil were analyzed and identified by gas chromatography － mass spectrometry ( GC-MS) ． The most abundant compound in anise oil was ( E) －anethole (88. 72% ) ． The main components of clove oil were Eugenol (68. 28% ) and Caryophyllene (20. 79% ) ． These results show that anise oil and clove oil are promising acaricides that could be used for controlling Varroa mites in beehives．
The efficiency of the anise (Pimpinella anisum LINN.) oil was tested to control varroa mite (Varroa
destructor Anderson & Trueman) on the honey bee (Apis mellifera Linnaeus) by evaporation using a
smoker or an electrical bobbin connected to a dry battery. Results showed that fumigation of a piece of sackcloth saturated with 4 ml of Anise oil per colony gave an efficiency of 56.2%, there was a significant difference at P=0.01 in comparison with untreated control. Meanwhile, the evaporation of 1.5 ml (0.5 ml of Anise oil and 1 ml Ethanol) using an electrical bobbin gave an efficiency ranged between 82.5 and 87%, the average was 84.4% and there was a significant difference at P=0.01 in comparison with untreated control. Results demonstrated that the addition of Ethanol to the Anise oil maintain its efficiency and decreased its loose. Evaporation of 1.5ml of Anise oil per colony gave an efficiency of 89.2%, meanwhile, adding 0.5 ml of Ethanol to 1 ml of Anise oil to the colony gave an efficiency of 86.3%. The efficiency was decreased to 72.3% in case of mixing 0.5 ml of Anise oil with 1 ml of Ethanol, where the evaporation of 1.5 ml Ethanol (treated control) per colony gave an efficiency of 41.5%. There was a significant difference at P=0.01 between the treatments and the treated control. We recommend using the Anise oil because it is a natural product, safe on honeybee products and can be used during the year.
AniseOil_Varroa.pdf (1.67 mb)
AniseOil_Varroa2.pdf (749.57 kb)