Acaricidal activity of an oleoresinous extract from Copaifera reticulata (Leguminosae: Caesalpinioideae) against larvae of the southern cattle tick, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae)

Abstract

The acaricidal activity of oleoresinous extract (oleoresin) from the copaiba tree, Copaifera reticulata was investigated. Oleoresin was dissolved with dimethylsulfoxide (DMSO) and mixed with distilled water at a rate of 0.4 ml of DMSO to 24.6 ml water. Rhipicephalus (Boophilus) microplus larvae were exposed to filter paper envelopes impregnated with different oleoresin concentrations. Four envelopes were impregnated with each tested solution. Thirty larvae between 14 and 21 days old were fasted and placed in each envelope. Bioassays were performed at 27 degrees+/-1 degrees C, RH>or=80% and a photoperiod of 12:12 h. Larval mortality was observed 24 h after treatment. Four replicates for each concentration were evaluated to determine lethal concentrations (LC). Oleoresin LC50 and LC99 values were 1579 and 3491 ppm, respectively. The potential use of oleoresin for control of R. (B.) microplus is discussed. The results of this study reinforce the importance of the preservation of C. reticulata in its natural Biome, as a potentially auto-sustainable medicinal resource among the flora of Amazonian forest.