D3203: Tick management properties of common yarrow (Achillea millefolium L.) essential oil against Ixodes scapularisand Dermacentor variabils ticks (Acari: Ixodidae)

In North America, the threat of contracting tick-borne illnesses has risen significantly over the past few years. Species such as the blacklegged tick (Ixodes scapularis) and American dog tick (Dermacentor variabilis) are known to vector several pathogens to humans and animals. This has led to an increased need for repellents that can help prevent tick bites. A potential solution is the implementation of natural products such as essential oils (EO), as an alternative to synthetic products. EO from common yarrow (Achillea millefolium L.) are promising candidate, as they have been reported to exert acaricidal and repellent activities on other acarines. Common yarrow plants were collected, flowers and leaves were separated, and the EO were extracted via the hydro-distillation method. Chemical composition of EO was characterized through GC-MS analysis. EO were tested on ticks at different concentrations for acaricidal and repellent activity, using adult immersion tests and horizontal bioassays, respectively. Yarrow flower EO were effective repellent and acaracide against I. scapularis but not for D. variabilis. To protect the active ingredient and enhance bioactivities, a nanoemulsion with 5% v/v yarrow EO was prepared. The encapsulation of the oil in a nanoemulsion formulation improved the repellent effect on I. scapularis but did not show acaracidal activity.