The use of medicinal plants has been a longstanding practice of mankind, helping to spread the therapeutic virtues of different plant extracts, due to their medicinal effects. In the search for effective natural alternatives for ailments that indirectly affect man, medicinal plants have been used in veterinary medicine, in an attempt to eliminate or reduce the action of B. microplus ticks, which can cause damage to cattle. For many years, chemical products have been used in this control. However, after some time ticks acquire drug resistance, as a result of continuous use. Thus, the objective of this paper was to evaluate the effect of hydrolates and aqueous extracts of carqueja [Baccharis trimera (Less). DC], alfavaca (Ocimum gratissimum L.), necroton [Vernonia condensata (Baker) H. Rob.], chamomile [Chamomilla recutita (L.) Rauschert] and also the essential oil of alfavaca (Ocimum gratissimum L.). The assays for larvae of B. microplus were carried out by impregnating the paper filter with the substances. The results showed that all the aqueous extracts were ineffective; the hydrolate of carqueja and necroton presented efficiencies around 30%, requiring further tests to prove. Among the results, we observed that the alfavaca hydrolate showed an efficiency of 76.7% at a concentration of 100% and the pure alfavaca oil showed a larvicidal action of 100%, indicating this plant's potential to reduce ticks, specifically in the control of B. microplus.
tick; Baccharis trimera; Ocimum gratissimum; Vernonia condensata; Chamomilla recutita
