The emulsions of the stem and root bark extracts of K.
uguenensis gave complete larval mortality at a concentration of 50
μg/ml within 3 days when tested under laboratory conditions (Fig
1; Table 1). On the other hand, slightly different results were
obtained when the assay was done under semi-field conditions
where the activities of the extracts took several days (Fig 1;
Table 1). At concentration of 200 μg/ml, the time taken to
kill 80% (LT80) of larvae and pupae for the root bark extract
was 8.28 days and that for the stem bark extract was 12.47
days (Fig 1; Table 1) and both extracts prolonged the time
of larval development relative to the control. For example,
until day 8, larvae in the control ponds had all pupated
while no pupa was emerged in the ponds treated with root bark
extracts. Neither extract caused significant larval and
pupal mortality below 200 μg/ml and after 14 days post treatment.