The efficacies of 5 insecticides against hard ticks Hyalomma asiaticum, Haemaphysalis longicornis and Rhipicephalus sanguineus.

At present, chemical-based tick control strategies are still the most efficient and widely used methods in control of ticks and tick-borne diseases. In this study, the efficacies of lambda-cyhalothrin, beta-cypermethrin, emamectin benzoate, spirotetramat and hexaflumuron in vitro were evaluated against Hyalomma asiaticum, Haemaphysalis longicornis and Rhipicephalus sanguineus that are widespread and able to transmit a variety of human and animal diseases in China. The results showed that the LC (lethal concentration) 50 of lambda-cyhalothrin, beta-cypermethrin, emamectin benzoate, spirotetramat and hexaflumuron were 22.05, 107.35, 287.62, 432.25 and over 6250 mg/L to Hy. asiaticum engorged nymphs, respectively. The LC50 of lambda-cyhalothrin and beta-cypermethrin were each to 100.69 mg/L and 340.05 mg/L against Hy. asiaticum unfed adults. In addition, 50 mg/L of lambda-cyhalothrin could completely inhibit engorged females of the 3 tick species to lay eggs. These results indicate that lambda-cyhalothrin has the highest efficacy and broadest spectrum for against the 3 tick species. The present study provides some information for selecting chemical acaricides in control ticks and tick-borne-diseases, as well for preparing acaricide mixtures to improve killing efficacy, and retard the advent of tick-resistance of acaricides in China.