Insecticide activity of sodium ricinoleate on Aedes (Stegomyia) aegypti (Linnaeus, 1762)

Resumo

This research has been dedicted to developing an insecticide taken from plants to combat the major vector of dengue fever virus in Brazil. Sodium ricinoleate, derived from the oil of Ricinus communis L., presented with insecticidal activity in preliminary tests carried out in Bioprospection, using native plants. The objective was to evaluate the deleterious effects of sodium ricinoleate on A. Aegypti, and to determine the lethal concentration (CL). The experiment was carried out with the third instar larvae, 25 per treatment, in quadruplicate. Concentrations of solution were tested: 1% (1 mg.dL-1), 0,5% (0,5 mg.dL-1), 0,1% (0,1 mg.dL-1), 0,05% (0,05 mg.dL-1) and 0,01% (0,01 mg.dL-1), respectively, diluted in water. To calculate the lethal concentrations (LC) the mortality of larvae was observed 24hours after the treatments. It is concluded that sodium
ricinoleate causes 90% mortality of the larvae of A. aegypti in concentrations up to 0,2025 mg.dL-1. Sub lethal doses, lower than CL50, in A. aegyti larvae causes total mortality of larvae or pupae stage, no adults emerge from these treatments.