Resistance of Rhipicephalus microplus ticks against synthetic pyrethroids from different places of Rewa district of Madhya Pradesh, India

Continuous and indiscriminate use of synthetic acaricides contribute to the development and establishment of acaricide-resistant tick populations. Monitoring of acaricide resistance in field ticks and use of suitable practices are essential for managing tick populations, infesting animals. In the present study, adult immersion test (AIT) was used for evaluation of resistance against commercially available synthetic pyrethroids (deltamethrin and cypermethrin) in Rhipicephalus microplus ticks collected from various villages of Rewa district of Madhya Pradesh, India. All the eight isolates of R. microplus were found resistant with deltamethrin and their resistance factors (RFs) were between 3.91 to 57.92, whereas, seven isolates were found resistant with cypermethrin and their resistance factor ranges from 0.56 to 9.98. Lethal concentrations (LC50 and LC95), confidence intervals (CI) and slope(s) were estimated by probit analysis and the highest and lowest level of resistance appeared in Sagra Bekchera and Silpara isolates of R. microplus for both deltamethrin and cypermethrin. It was observed that of the two compounds used for tick management, the resistance to deltamethrin was comparatively higher than cypermethrin. Data generated on pyrethroid resistance status of ticks in this region will provide new insights in acaricidal resistance scenario particularly from remote areas of this region and will help in formulating suitable tick management strategy.