In vitro Analysis of the Efficacy of Selected Commercial Acaricides on The Cattle Tick Rhipicephalus (Boophilus) annulatus (Acari: Ixodidae)

Ticks are important to the Nigerian livestock industry because of their ability to cause huge economic loss directly or indirectly. Chemical acaricides have played important roles in control of tick infestation for many years but development of acaricide resistance as being reported worldwide is a huge problem facing the livestock industry and the veterinarians. Thus, this study evaluated the efficacy of available commercial acaricides on Rhipicephalus (Boophilus) annulatus. Using Adult Immersion Test (AIT): the LC50, inhibition of oviposition, control and resistance rates, gradation of tarsal reflexes were determined for ticks treated with different acaricides at five different concentrations the discriminating dose (DD) (the manufacturer’s recommended dose) and four other different concentrations of two below and two above the DD with the aid of prohibit regression. The association between weight and number of eggs laid was analyzed by linear correlation. Macrocyclic lactone(66.7%), Phenylpyrazole (62.5%), Cypermethrin (62.5%), Formamidine(33.3%) and Phenylpyrazole(13% egg production), Macrocyclic lactone (18% egg production), Cypermethrin(20% egg production), Formamidine(49% egg production) have the highest to lowest percentage control and oviposition inhibition values respectively. The LC50 of (Formamidine), (Phenylpyrazole), (Synthetic pyrethroids), (Macrocyclic lactone) against adult R. (B.) annulatus were 100, 8000, 2300 and 6000ppm respectively.The demonstration of acaricide resistancedevelopmentas demonstrated by the ticks in laying of eggs after dipping in acaricideis a call to the need for discovery and use of alternative tick control methods with good therapeutic dose and the need for continuous evaluation of available acaricide.