DETECTION OF MULTI-ACARICIDE RESISTANCE IN RHIPICEPHALUS (BOOPHILUS) MICROPLUS (ACARI: IXODIDAE)

Engorged females of Rhipicephalus (Boophilus) microplus(Canestrini 1888) (Acari: Ixodidae) were collected from Jalandhar district, Punjab and acaricide resistance status was assessed by adult immersion test against various class of acaricides viz. organophosphates (malathion), synthetic pyrethroids (cypermethrin, deltamethrin and fenvalerate) and formamidines (amitraz). The regression graph of probit mortality of ticks plotted against log values of progressively increasing concentrations of acaricides revealed the slope of mortality and was used for estimation of various lethal concentrations. The LC50 (95% CL) and LC95 (95% CL) values (ppm) for amitraz [628.4 (592.8 - 666.1) and 1972.7 (1738.1 - 2239.01)], cypermethrin [37.83 (35.02 -40.85) and 183.07 (153.84 - 217.85)], deltamethrin [45.57 (40.32 - 51.49) and 441.56 (342.29 - 569.61)], fenvalerate [142.67 (132.22 - 153.94) and 585.04 (500.46 - 683.91)] and malathion [3436.7 (3251.4 - 3632.6) and 9555.0 (8208.8 - 11122.1)] were estimated. Alow-level resistance status was recorded against formamidines (amitraz), deltamethrin and malathion, whereas, the ticks were found susceptible for cypermethrin and fenvalerate. The dose response curves for egg mass weight, reproductive index and percent inhibition of oviposition were also evaluated for the studied tick population.