Independent and joint action of cis- and trans-permethrin on third instar of Triatoma infestans

ALZOGARAY RA; PICOLLO MI; ZERBA EN

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 1998 vol. 37 p. 225 - 230

0739-4462

The toxicity of pure cis- and trans-permethrin or mixtures of the two isomers topically applied to first, third, and fifth instar nymphs of Triatoma infestans at 26 °C was determined. The cis- isomer was more active than the trans- isomer in the three stages evaluated. When the two isomers were simultaneously applied to first instar nymphs, an additive effect was observed. Similar treatments of third and fifth instar nymphs resulted in an antagonistic effect. In third instar nymphs, the cis-isomer was more active than trans-isomer at all the three temperatures assayed (16, 26 and 36 °C). The toxicity of the cis-isomer was lower at 36 than at 16 or 26 °C. Temperature had no significant effect on the toxicity of the trans-isomer within the temperature range assayed. The toxicity of either isomer to third instar nymphs was not affected by pretreatment of nymphs with PBO (an inhibitor of mixed-function oxidases activity) or TPP (an inhibitor of esterase activity),suggesting that these detoxification pathways are not relevant in the metabolism of cis- or trans-isomers.