RESUMEN
In the present study, the acaricidal effects of caffeic acid, nortriptyline, precocene I and quercetin against Rhipicephalus annulatus (syn. Boophilus annulatus) Say (Acari: Ixodidae) were evaluated. Adult immersion technique (24 ticks immersed for 2 min in one dilution of the compound) was used for the assessment of the effects of caffeic acid (0.39-100 mg/mL), nortriptyline (0.625-50 mg/L), precocene I (0.004488-5 mg/mL) and quercetin (6.25-100 mg/mL) against R. annulatus. Adult tick mortality, reproductive index, inhibition of fecundity and hatching were calculated. Caffeic acid, nortriptyline, precocene I and quercetin revealed very low adult mortality and inhibition of fecundity, even at the highest concentration tested. Quercetin (>50 mg/mL) caused blocking of hatching of eggs.