Resistance status of one host tick Rhipicephalus microplus of arid and semi-arid region of Gujarat, India

Abstract

Ticks cause various harmful effects on livestock with a combination of direct and indirect effects. Resistance status of one host tick Rhipicephalus microplus from two districts, Banaskantha (BK) and Patan (PN) of North Gujarat was tested against synthetic pyrethroids (deltamethrin and cypermethrin) by adult immersion test (AIT).Ticks were collected from six talukas each from BK and PN. Tick isolates from eight places showed resistance against deltamethrin having resistance factor ranging from 2.52–22.59. Further, isolates from six places, Ranuj, Dhanera, Radhanpur, Patan, Dhaneri and Kheda showed resistance against cypermethrin with resistance factor in range of 2.42–18.66. The results reveal a remarkable variance of susceptibility to deltamethrin and cypermethrin in the R. microplus populations studied. Isolates from PN district, from talukas Ranuj, Patan, Radhanpur, and Sidhpur were resistant to deltamethrin with resistance level II in all the places and resistance factors estimated were 16.73, 16.7, 9.64, and 7.25, respectively. Tick isolated from Patan, Radhanpur and Ranuj were resistant to cypermethrin with resistance level II, II and I, respectively with resistance factor of 11.74, 6.74 and 2.42, respectively. The slope and R2 values for deltamethrin resistant tick isolates were in the range of, 0.64 ± 0.33 to 2.28 ± 0.21 and 50.0 to 97.62; and that for cypermethrin resistant tick isolates was 0.64 ± 0.33 to 2.28 ± 0.21 and 46.53 to 88.26 respectively. The finding is significant, as it reports the development of resistance against most commonly used acaricides in very large area of North Gujarat and the data generated would be useful in formulation of effective control strategies against ticks of this large geographic region.