LARVICIDAL ACTIVITY OF EXTRACTS FROM SIX PLANT SPECIES ON LARVAE OF Culiseta longiareolata (DIPTERA; CULICIDAE)

Because of the environmental problems and dangers to human health caused by chemical insecticides, the use of natural biocides seems to be imperative. In this context toxicity tests were carried out according to the protocol of the World Health Organization (WHO) for six aqueous extracts of leaves of: Ambrosia Maritima, Hertia centifolia, Xanthium strumarium, Datura stramonium, Solanum elaeagnifolium, and Salvea verbena, with a series of three doses for each extract. The evaluated extracts showed good larvicidal activity against the fourth instar larvae of Culiseta longiareolata mosquito, the decoction method is used for the preparation of extracts. The mortality rate increases depending on the concentration of the used extract and the exposure time, with interesting lethal concentrations LC50% and LC90%, A. Maritima (11.65 μg / ml and 52.40 μg / ml) after 120 hours and D. stramonium (16.94 μg / ml and 28.36 μg / ml) after 96 hours. While the lethal times LT50% and LT90% do not exceed (0,01 day to 2,14 day) at a dose of 219.9 μg / ml of S. elaeagnifolium (0,95 day to 1,34 day) with a dose of 160 μg / ml of H. centifolia.