Effect of aqueous extracts of Baccharis trimera on development and hatching of Rhipicephalus microplus (Acaridae) eggs

This study evaluated the effects of aqueous extracts of Baccharis trimera (Less.) DC (Asteraceae), colloquially known as carqueja, on egg production, and hatching rate of larvae of Rhipicephalus microplus. Plant samples were collected in Montes Claros, north of Minas Gerais, Brazil. Adult female ticks were distributed into 24 homogeneous groups of 10. The in vitro test was performed by immersing each group in 10 ml solutions of aqueous extracts at 50, 100, 150, or 200 mg of fresh leaves ml−1. These concentrations were compared with distilled water as negative control and a commercial product as positive control and the tests were repeated four times. The carqueja extract at concentrations of 150 and 200 mg of fresh leaves ml−1 showed 100% efficacy in inhibiting egg hatching and therefore could have potential as an acaricide.