Screening of the acaricidal efficacy of phytochemical extracts on the cattle tick Rhipicephalus (Boophilus) microplus (Acari: ixodidae) By Larval Immersion Test

The objective of the study was to determine the acaricidal efficacy of selected native plants from Yucatán, Mexico on acaricide resistant larvae of Rhipicephalus (Boophilus) microplus. Methanolic extracts from roots, leaves, stems, and stem barks of 15 plants were tested using the modified larval immersion test. A final concentration of 10% (100 mg/ml) of plant crude-extract was used. The percentage mortality from different plants and extracts were: Petiveria alliacea leaves (95.7±2.9 %) and stems (99.2±0.5 %); Diospyros anisandra leaves (87.9±8.6 %) and stem bark (98.8±1.0 %); Havardia albicans leaves (93.0±12.0 %), Caesalpinia gaumeri (90.1±4.8 %) and Capraria biflora (86.6±9.9 %), stems of Solanum tridinamum (98.0±1.7 %) and Solanum erianthum (97.8±1.8 %), stem bark of Bursera simaruba (99.1±0.7 %) and Cassearia corymbosa (99.5±0.5 %); and the root of Ocimum micrantun (87.0±3.2 %). We concluded that plants from Yucatan, Mexico showed a high acaricidal efficacy that could be used to control R. (B.) microplus acaricide resistant larvae. P. alliacea, Havardia albicans and Caesalpinia gaumeri were of the most encouraging plants to be used as an acaricide. Further studies are needed to evaluate these plants on adult ticks (in vivo conditions) and to identify the active compound(s) on R. (B.) microplus.