Synergistic properties of essential oils of eucalyptus (Eucalyptus globulus) and lemon grass (Cymbopogon flexuosus) against cattle tick, Rhipicephalus microplus

ABSTRACT The anti-tick efficacy of eight commercially available essential oils (EOs), viz., Neem (Azadirachta indica), castor (Ricinus communis L.), lemon grass (Cymbopogon flexuosus), eucalyptus (Eucalyptus globulus), curry leaves (Murraya koenigii), garlic (Allium sativum), sage (Salvia officinalis), and rosemary (Rosmarinus officinalis), was screened in vitro against Rhipicephalus microplus ticks. Each of the EOs were diluted in 2% Triton X-100 and 10% ethanol to prepare working concentrations and were tested against IVRI-I strain of Rhipicephalus microplus. The mortality, egg masses, and inhibition of oviposition (IO) were used to determine treatment effectiveness. The EOs of C. flexuosus, E. globulus, S. officinalis, and R. officinalis showed more than 95% efficacy at the tested concentrations. While, EOs of A. indica, R. communis, M. koenigii, and A. sativum were found 16–33% efficacious. Six different combinations of the most effective EOs (C. flexuosus and E. globulus) were prepared and tested for anti-tick activity. The combination C, F, and H showed 100% mortality at 4% concentration. The combination H was found more economical than ivermectin for animal treatment indication that it can be used effectively for the development of potent antitick formulation for the management of tick populations.