To evaluate persistence, 10 % concentrations of
C. citratus and S. aromaticum oils were used over a period of 10 days and compared with a fresh sample(day 0). The results are shown in Table 5. The larvicid al efficacy of stored samples varied slightly over time.
Complete larval mortality among third instars (100 %
mortality) was observed with S. aromaticum oil, and
the larval mortality among fourth instars slightly decreased over time. There was no significant difference
in mortality rates for days 1, 5, and 10 among Ae.
aegypti L3 and L4 exposures. For C. citratus oil, there
was no difference in mortality among third instars
(P > 0.05) or over the period of 10 days. However, the larval mortality of fourth instars decreased to 50 % after
samples had been stored for 10 days.
Table 6 shows the persistent efficacy of 10 % C. citratus
and S. aromaticum oils against third- and fourth-instar An.
dirus larvae. Both oils produced 100 % mortality on days 1,
5, and 10 against third-instar An. dirus larvae. However,
S. aromaticum oil was slightly more lethal against fourth instar An. dirus larvae than C. citratus oil. The test on the
stability for both oils up to 10 days indicated no significant
effects caused by storage duration. Both oils had slightly increased LT50 rates from day 1 to day 10 (Fig. 5).