Correspondence: Determination of LC50 of malathion, dicofol and α-cypermethrin on semi-engorged females of the brown dog tick, Rhipicephalus sanguineus (Acari: Ixodidae)

Semi-engorged females of the brown dog tick, Rhipicephalus sanguineus (Latreille, 1806) were dipped in different concentrations of three acaricides (malathion, dicofol and α-cypermethrin) for three minutes. Probit analysis has been done using a proper software and the results were presented in terms of lethal concentrations of acaricides affording 50% mortality (LC50). As per probit analysis, dicofol was the most effective acaricide with LC50 88.6 ppm (79.419–97.429 ppm fiducial limits) followed by malathion (LC50 = 1299.8 ppm; 1223.7–1375.5 ppm fiducial limits). This work can be utilized as a convention with different chemicals, to determinate the LC50, basic steps for investigations of control, resistance and conduct of ticks treated with acaricides, especially the brown dog tick, Rhipicephalus sanguineus. Additionally, the knowledge of the LC50 gives an idea on the strength of chemicals, the affectability of arthropods to them and even gauges on nuisance control.