The efficacy of etoxazole against Haemaphysalis longicornis (Acari: Ixodidae), as a tick control agent

Abstract

The efficacy of etoxazole, an insect growth regulator, against Haemaphysalis longicornis was examined by several laboratory tests and field trials. It showed 100% inhibition of egg-hatching at a dose of 1.0μg administration onto engorged female ticks. Against engorged larvae, 100% molting inhibition was observed when the agent was applied at a dose of 0.1μg/cm^2 on a glass dish for 0.5 hr as well as in engorged nymphal tick dosing 0.1μg/cm^2 for 3.5 hr or 1.0μg/cm^2 for 0.5 hr. In the field examination, a solution containing 1.0% of etoxazole was applied onto the back of cattle by the pour-on method. After administration, engorged ticks on the cattle were collected longitudinally and then examined for molting of larvae and nymphs and for hatching of eggs laid by sensitized female ticks. At one-day after administration, inhibition rate was 100% against both molting and hatching. The inhibition effect of the agent gradually decreased but seemed to be maintained for three weeks. The results showed etoxazole inhibited the development of ticks in all of their life-stages and, therefore, it would be a promising agent as an applicable acaricide in the fields.