Laboratory-reared
Lutzomyia longipalpis
(Lutz and Neiva 1912) was tested with extracts of two ichthyotoxic plants,
known as
timbós
, used as fishing poison in the Amazon. Phlebotomines,
L. longipalpis
, and plants,
Antonia ovata
and
Derris amazonica
, were collected in the Raposa-Serra do Sol Indian Reserve, a focus of
visceral leishmaniasis in the State of Roraima, Brazil. Extracts were
prepared from dried leaves of
A. ovata
and roots of
D. amazonica
that were percolated in water, filtered and dried out at 50°C. The
solid extract obtained was diluted in water at 150, 200 and 250 mg/ml.
The solution was blotted in filter paper placed at the bottom of cylindric
glass tubes containing sand flies. For each plant extract and dilution,
two series of triplicates with 5 male and 5 female specimens of
L. longipalpis
were used. Mortality was recorded every 2 h during 72 h of exposure. At
72 h the mortality was as high as 80% for extracts of
A. ovata
(LD
50
= 233 mg/ ml), and 100% for
D. amazonica
(LD
50
= 212 mg/ ml) whereas in the control groups maximum mortality never surpassed
13%. Preliminary assays indicated that
A. ovata
and
D. amazonica
displayed significant insecticide effect against
L. longipalpis
.
