Evolution of the larvicidal activity at different dilutions of Satureja thymbra EO. Twenty-five third instar larvae of a laboratory colony of Anopheles gambiae (susceptible strain) were used. Mortality % was assessed at increasing concentration of EOs collected before, during, and after flowering. Four replicates were set up for each concentration. Water was used as negative control. The activity of the EOs expressed as LC50 was 0.15 ± 0.002; 0.21 ± 0.013; and 0.15 ± 0.087 μg/ml (mean ± sd) for the samples A, B and C, respectively.