Chemical Characterization and Acaricidal Potential of <i>Echinops kebericho</i> Mesfin Root Essential Oil Against <i>Varroa destructor</i> Anderson & Trueman

Honey bees are vital pollinators, contributing to one-third of the global food crop pollination. Despite their importance, bee populations have been declining worldwide. One of the major drivers of this decline is Varroa destructor, an ectoparasitic mite that feeds on adult bees and developing brood. Synthetic acaricides are commonly used for mite control; however, their extensive application has resulted in acaricide resistance and contamination of bee products, raising concerns about environmental and human health. Consequently, there is an urgent need for safe and effective alternative control strategies. Essential oils are known for their acaricidal properties, and in Ethiopia, Echinops kebericho has demonstrated such activity, although its efficacy against Varroa mites has not been previously investigated. In this study, essential oil was extracted from the roots of E. kebericho, its chemical composition was characterized using GC-MS, and its acaricidal activity was evaluated using a complete exposure method. Hydrodistillation yielded 0.4% paleyellow oil, in which 22 compounds were identified accounting for 67.09% of the total composition. The major constituents were isobornylene (11.27%), 1,2-diethyl-3,4-dimethylbenzene (9.75%), and caryophyllene oxide (7.37%). The essential oil exhibited strong, dose-dependent acaricidal activity against Varroa mites, with a 4-h LC₅₀ value of 161.89 µg/ml. However, its potency was lower than thymol, which showed an LC₅₀of 54.42 µg/ml. These findings indicate that E. kebericho essential oil has potential as a natural Varroa control agent, and warrants further investigation to assess its efficacy, safety, and practical application in apiculture.