Residual effect of lambdacyhalothrin on Triatoma infestans

• Main Authors: Esteban A. Ferro, Antonieta Rojas de Arias, M. Elena Ferreira, Luis C. Simancas, Luis S. Rios, Jorge M. Rosner
• Format: Article
• Language: English
• Published: Instituto Oswaldo Cruz, Ministério da Saúde 1995-06-01
• Series: Memórias do Instituto Oswaldo Cruz.
• Subjects: Triatoma infestans; lambdacyhalothrin; pyrethroids; insect control
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0074-02761995000300019

Insecticidal residual effect and triatomine infestation rates in houses of a community fumigated with lambdcyhalothrin (Icon) are reported. No mortality was observed in 5th-instar Triatoma infestans nymphs in 72-hr exposure test on three different surfaces, one month after fumigation for a dose of 31.5 mg am/m2. However, during post-exposure observation a mortality of 60% was recorded for those insect exposed on sprayed woodboard. The results observed with mud-containing treated walls, were markedly poorer (0% of mortality). Twelve month after spraying 40% of mortality was observed on first-instar T. infestans nymphs in 72-hr exposure test on woodboard, but lower mortality rates were observed in mud-containing materials. When the effect of deltamethrin (109 mg ai/m2) and lambdcyhalothrin (94 mg ai/m2) was compared, the former did not appear to be superior at similar loads. Both have showed a mortality rate of 30% on 5th-instar T. infestans nymphs three months post-fumigation. The dose utilized in the field fumigation was enough to get a significant (p < 0.0001) control of triatomine domestic infestation, since it was sufficient to keep 95% of the houses uninfested throughout 21 months following treatment, when compared with baseline situation. A remarkable knock-down effect on adult and nymphs forms of the insect and a high in situ mortality were observed as a result of its application, even at very low doses.