The southern cattle tick (Rhipicephalus microplus) tyramine receptor: A potential target of biopesticides

The southern cattle tick, Rhipicephalus (Boophilus) microplus, vectors the causative agents (Babesia spp.) that results in Texas Cattle Fever.  The southern cattle tick is endemic to Mexico, and therefore is a continued threat to the United States cattle industry. Currently there is a permanent quarantine zone along the Texas-Mexico border.  In recent years the southern cattle tick has been detected within and outside of this quarantine zone. The mainstay for control of the southern cattle tick has been the use of chemical acaricides, primarily coumaphos.  However, acaricide resistance has been reported among several classes of chemical acaricides.  Recently there has been an interest in using biologically-based acaricides to help control the southern cattle tick, including the use of essential oils and essential oil terpenoids.  Essential oils have previously been shown to be toxic to a variety of insects and ticks.  Additionally, a neurological mechanism of action has been suggested.  The presented research will focus on the development of a screening system to find essential oil terpenoids that are effective at the southern cattle tick’s tyramine receptor.