Acaricidal efficacy of Essentria® IC-3 and its active ingredients against acaricide resistant and susceptible strains of Rhipicephalus (Boophilus) microplus

Authors: SINGH, NIRBHAY - Guru Angad Dev Veterinary & Animal Sciences University; Miller, Robert; KLAFKE, GUILHERME - Desiderio Finamore Veterinary Research Institute (FEPAGRO); Goolsby, John; Perez De Leon, Adalberto - Beto

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/23/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary: Ticks and tick-borne diseases are a major constraint for a sustainable cattle industry in tropical and subtropical regions of the world. Presently, chemical acaricides represent the most widely used tick control strategy, but it has several disadvantages including resistance development, environmental impact, and persistent effects. Herbal acaricides using plant products and their combinations would be an eco-friendly tick control alternative. The acaricidal efficacy of Essentria® IC-3, an insect concentrate for crawling and flying insect pests and its active components, was evaluated against acaricide resistant and susceptible cattle tick laboratory colonies. These results will benefit farmers, ranchers, dairy and beef industry by providing totally natural alternative to chemical acaricides for effective control of the cattle fever ticks Rhipicephalus microplus, and Rhipicephalus annulatus. Essentria® IC-3 could also be used to complement existing control strategies for ticks in the transboundary region between Mexico and Texas, particularly against alternative host species such as nilgai and white-tailed deer where chemical acaricides can not be used as in cattle.

Technical Abstract: Ticks and tick-borne diseases are a major constraint for a sustainable cattle industry in tropical and subtropical regions of the world. The development of resistance to most of the commonly used acaricides leads to an attempt to screen herbal products and their combinations for their possible acaricidal activity to develop eco-friendly tick control alternatives. 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 through octopamine blocker technology. Essentria® IC-3 and its active components were evaluated for acaricidal activity against acaricide resistant strains (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. 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® IC-3 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® IC-3 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® IC-3 with resistance factor (RF) of 1.49 (Yucatan), and 2.20 (Fipronil resistant), but susceptibility against geraniol similar to Duetch strain was recorded in resistant strains. We report resistance against a herbal acaricide in cattle tick for the first time, possibly due to association with cross-resistance to fipronil.