The botanical monoterpenes linalool and eugenol hyperactivate and flush-out nymphs of Triatoma infestans

MORETTI AN; SECCACINI E; ZERBA EN; CANALE D; ALZOGARAY RA

JOURNAL OF MEDICAL ENTOMOLOGY

ENTOMOLOGICAL SOC AMER

Lugar: Lanham; Año: 2017 vol. 54 p. 1293 - 1298

0022-2585

Monoterpenes are the main components of essential oils. Some members of this chemical family present insecticidal activity. Triatoma infestans is the main vector of Chagas disease in Argentina, Bolivia, Paraguay and Perú. The objective of this work was to evaluate the effect of six monoterpenes (1,8-cineole, eugenol, linalool, menthol, α-terpineol and thymol) on the locomotor and flushing out activity of T. infestans. A video tracking technique was used to evaluate the locomotor activity of nymphs exposed to different concentrations of these chemicals applied as films on filter paper. Papers treated with acetone alone were used as negative controls, while solutions of tetramethrin were applied as positive controls. Only linalool and menthol produced hyperactivation. Flushing out was assessed under laboratory conditions using a standardized aerosolization method. All monoterpenes were applied at 1.5 g/m3. 1,8-Cineole, α-terpineol and thymol flushed out 10% or less nymphs. The average flushing out produced by eugenol was 36.7%. Values of Median Flushing out Time (FT50) could only be calculated for linalool and menthol (16.67 and 42.98 min, respectively). The FT50 value for the positive control tetramethrin (applied at 0.006 g/cubic meter) was 8.29 min. Following these results, the flushing out activity of a mixture of linalool and eugenol was evaluated. The FT50 of this 2:1 linalool:eugenol mixture was 40.73 min. Finally, flushing out assays performed in semi-field conditions showed similar results to those obtained at the laboratory.