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

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 LC 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 LC 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 LC. 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.