Ethanol extracts of 83 plants species belonging to the Asteraceae
(Compositae) family, collected in the State of Minas Gerais, Brazil, were
tested for larvicidal activity against the mosquito Aedes fluviatilis -
Diptera: Culicidae). The extract from Tagetes minuta was the most active
with a LC90 of 1.5 mg/l and LC50 of 1.0 mg/l. This plant has been the
object of several studies by other groups and its active components have
already been identified as thiophene derivatives, a class of compounds
present in many Asteraceae species. The extract of Eclipta paniculata was
also significantly active, with a LC90 of 17.2 mg/l and LC50 of 3.3 mg/l
and no previous studies on its larvicidal activity or chemical composition
could be found in the literature. Extracts of Achryrocline satureoides,
Gnaphalium spicatum, Senecio brasiliensis, Trixis vauthieri, Tagetes patula
and Vernonia ammophila were less active, killing more than 50% of the
larvae only at the higher dose tested (100 mg/l).