Assessment of variation in in vitro acaricidal activity of eugenol and 1,8 cineole against bovine Rhipicephalus...

This study investigated the acaricidal efficacy of eugenol and 1,8-cineole against Rhipicephalus (Boophilus) microplus ticks using in vitro adult immersion test (AIT) and larval packet test (LPT). Eugenol and 1,8-cineole were tested at concentrations of 80, 40, 20, 10, and 5 mg/mL for AIT. The concentrations of eugenol used were 100, 50, 25, 12.2, 6.25, 3.125, 1.56, and 0.781 mg/mL and 1, 8 cineole were 100, 50, 25, 12.2, 6.25, 3.125 mg/mL for LPT. The results showed that eugenol achieved 100% mortality for adult ticks at 80 mg/mL and for larvae at 6.25 mg/mL, indicated a high level of efficacy. In contrast, 1,8-cineole resulted in 60% adult tick mortality at 80 mg/mL and 80% larval mortality at 100 mg/mL. The LC₅₀ values were determined as 4.20 mg/mL and 1.808 mg/mL for eugenol in AIT and LPT, respectively, while 1,8-cineole had LC₅₀ values of 5.70 mg/mL and 16.34 mg/mL for AIT and LPT, respectively. These findings indicated that eugenol is more effective than 1,8-cineole in killing tick larvae, although both compounds demonstrated similar efficacy in adult tick death by LC₅₀. The better efficacy of eugenol suggested its potential as potent herbal acaricide, while 1,8-cineole still shows promise as an alternative. The results supported the potential of these compounds for developing effective, herbal-based tick control solutions.