The effect of thyme (Thymus caucasicus) ethanol extract on Varroa mite (Varroa destructor), an ectoparasite mite of Apis mellifera meda (Hym: Apidae)

Abstract

Chemical control of the Varroa mite (Varroa destructor), which is one of the most important pests of honey bees, is practiced on a worldwide scale. However, because of abundant use of different acaricides, the mites have become resistant to many of them. We chose to apply non-synthetic chemicals for control of Varroa mites by using thyme (Thymus caucasicus) ethanol extract on honey bees. In September-October 2013, we collected wild thyme growing in Kurdistan mountains, ground it, and its ethanol extract was made by using 95% ethylic alcohol. We used a randomized complete design with ten treatments of different concentrations of ethanol extract of thyme as a statistical model and one control with pure 95% ethanol with four replications. The interior temperature of the brood chamber was measured to be 30 ± 1°C, and the ambient temperature surrounding them was 33 ± 2°C. We sprayed the extracted thyme solution on honey bees and counted the number of dead mites by picking them out from the bottom board of each hive at every 12 h, 24 h, and 48 h intervals after spraying. The results showed that the use of the thyme extract influenced significantly the percentage of mortality of dead mites in the extract-sprayed treatment and the control treatment. The percentage of mortality of the honey bees in control hives and the honey bees treated by thyme ethanol extract did not have a significant difference. Results of our experiment using ethanol extract of thyme showed that its use in hives was safe without a high risk of mortality for honey bees.

Controlling Varroa destructor Infesting Honey Bee Apis mellifera using Essential Oils as Diet Supplements and as Impregnated Paper

“…On the other hand, mustard oil impregnated papers was proved to be the least effective treatment. The presented results are in agreement with those reported by Rahimi et al (2017) who found that the use of the thyme extract influenced significantly the percentage of mortality of mites. Also, results of Ghafoor and Faraj (2017) showed that thyme oil (50% concentration) had the best results for controlling Varroa among other tested plant oils according to the results in both laboratory and apiary.…”

“…Essential oils or any of their components have been tested to control the mite V .destructor. Their toxicity, repellent or attractive effect towards the mite and their influence on the mite's reproduction have been evaluated (Ruffinende et al, 2007;Islam et al, 2016;Rahimi et al, 2017;Light et al, 2020).…”