To investigate biological stability, the persistence of larvicidal
activity was determined by keeping the essential oil dissolved
in water for various periods of time. Assays were run with
10 % C. citratus and S. aromaticum oils after they had been
dissolved in water and stored for 1, 5, and 10 days. All test
containers were tightly covered with plastic lids and placed at
room temperature in an area without sunlight. The larvicidal
bioassay followed WHO standard procedures. The exeriment was performed in five replicates. Mortality and survival were counted 24 h after placement.