Efficacy of carvacrol on Rhipicephalus (Boophilus) microplus engorged female ticks (Canestrini, 1887) (Acari: Ixodidae): effects on mortality and reproduction

Abstract

The activity of carvacrol was evaluated in R. microplus female ticks by estimating the mean lethal concentration (LC₅₀) and the acaricidal efficacy. Ticks were subjected to the Adult Immersion Test (AIT) to calculate LC₅₀. From this value, the AIT was performed again at the concentrations of 20%, 40%, 60%, 80% and 100% of the LC₅₀. Two control groups were established: one treated with distilled water and one with the solvent (ethanol 50%). The following parameters were evaluated: female weight before oviposition, egg mass weight, pre-oviposition and incubation period, hatching percentage, egg production index, fecundity rate, estimated reproduction, reduction in oviposition and hatching, and product efficacy. The obtained LC₅₀ was 20.11 mg/mL. Egg mass weight, egg production index, pre-oviposition and fecundity rates of groups treated with 80% and 100% of LC₅₀ were statistically different when compared to control groups. The product efficacy in groups treated with 100% of LC₅₀ was 61.10%.

Graphical Abstract

Keywords:

• Phytotherapy
• LC50
• ticks
• cattle
• control

Additional information

Funding

This research was financially supported by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) and FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo, Award Number 2104/18453-4).