author(s)
Sudha Rani R, Placid ED’Souza, SM Byregowda, BM Veeregowda, PP Sengupta, BM Chandranaik and PM Thimmareddy

abstract
Acaricide resistance is a major problem in sheep population that hinders the control of the ticks in Karnataka and worldwide. In view of the increasing reports of acaricidal resistance world wide a study was designed to evaluate the efficacy of Amitraz, Deltamethrin and Cypermethrin using larval packet test (LPT) and adult immersion test with differentiating dose (AIT-DD) against different species of ticks. The tick species involved in this study were Haemaphysalis bispinosa, Haemaphysalis intermedia, Haemaphysalis kutchensis, Hyalomma marginatum issaci, Hyalomma anatolicum anatolicum, Rhiphicephalus haemaphysaloides and Rhipicephalus sanguineus. In LPT, amitraz at 0.2% induced 100 percent mortality against all species of ticks, whereas cypermethrin and deltamethrin induced 100 percent mortality at 0.3% and 0.4% against all species of ticks. In AIT-DD test amitraz was found to be susceptible at 2.5g/ltr whereas cypermethrin at 0.05g/ltr and deltamethrin at 0.075g/ltr was found to be resistant against all species of ticks in this study.