Vol. 9, Issue 9, Part D (2025)

Ticks are significant ectoparasites of livestock, acting as vectors of various pathogens and causing major economic losses, especially in tropical regions like India. Due to the lack of alternative control strategies, the extensive reliance on acaricides has resulted in the development of resistance in Rhipicephalus (Boophilus) microplus populations. This study aimed to assess the resistance status of this tick species against deltamethrin and cypermethrin in six districts of Telangana. The findings provide baseline data essential for developing region-specific tick control strategies. LPT was carried out with 10-12 day old live larvae with same concentrations which were used for adult immersion test. The LC₅₀ values of 63.05, 51.18, 118.8, 141.8, 191.5, 35.3 and 139.7, 63.97, 426.9, 391.7, 402.7, 94.6 against Deltamethrin and Cypermethrin were recorded in Rangareddy, Warangal, Mahaboobnagar, Karimnagar, Khammam and Nizamabad districts, respectively. In the present study, out of six field isolates tested with Deltamethrin, two isolates (Warangal, Nizamabad) were resistant at level I and four (Rangareddy, Mahaboobnagar, Karimnagar, Khammam) were resistant at level II. Among the six isolates tested with Cypermethrin, two isolates (Warangal and Nizamabad) were susceptible and four were (Rangareddy, Mahaboobnagar, Karimnagar, Khammam) resistant at level I. The results suggested that the resistance to Cypermethrin was low in Telangana as compared to Deltamethrin.