Pharmacology and Ethnopharmacology

Biography

Biography: Nirbhay Kumar Singh

Abstract

Ticks and tick-borne diseases are a major constraint for the sustainable cattle industry in the tropical and subtropical regions of the world. The developments of resistance to most of the commonly used acaricides lead to an attempt to screen herbal products and their combinations for their possible acaricidal activity to develop an eco-friendly tick control alternative. Essentria^® IC-3 insect concentrate for crawling and flying insect pests contains rosemary oil (10%), geraniol (5%) and peppermint oil (2%), and acts on target pests by octopamine blocker technology. Essentria and its active components were evaluated for acaricidal activity against acaricide resistant (Yucatan and El Zamora) and susceptible strains (Deutch) of cattle tick, Rhipicephalus (Boophilus) microplus by Larval Packet test (LPT) using 14-21 days old unfed larvae. The efficacy was assessed by measuring percent larval mortality and estimating lethal concentrations at 50% (LC₅₀) and 95% (LC₉₅) with 95% confidence limits (CL) using probit analysis. A concentration-dependent mortality response was observed with Essentria and geraniol whereas; rosemary oil and peppermint oil failed to produce such response against any tick strain. The LC₅₀ and LC₉₅ (95% CL) values of Essentria and geraniol against Deutch strain were 0.55% (0.55-0.56) and 0.10% (0.98-0.10), and 0.59% (0.58-0.60) and 0.11% (0.10-0.11), respectively. Interestingly, the acaricide resistant strains showed resistance to Essentria with resistance factor (RF) of 1.49 (Yucatan) and 2.20 (Fipronil resistant) but against geraniol, susceptibility similar to susceptible (Duetch) strain was also recorded in resistant strains. We report resistance against a herbal acaricide in cattle tick for the first time, possibly due to cross-resistance to fipronil.