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/m^2. 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 4096
of mortality was observed on first-instar T. infestans
nymphs in 72-hr exposure test on woodborad but lower
mortality rates were observed in mud-containing materials.
When the effect of deltamethrin (109 mg ai/m^2) and
lambdacyhalothrin (94 mg ai/m^2) 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 montbs 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 form of the insect and a high in situ
mortality were observed as a result of its application,
even at very low doses.
