Abstract:
Objective: To evaluate immature mosquitocidal properties of Xanthium strumariumplant
extracts against Culexmosquitoes at Entomology Laboratory, Maraki Campus, University of
Gondar.
Methods:The immature mosquitocidal activity of plant extracts was tested by following
World Health Organization recommended protocol. Acetone, methanol and water extracts were
prepared at 50, 100, 150, 200 and 250 mg/L concentrations and tested against third and fourth
instar larvae and pupae of Culexmosquitoes. The mortality rate of immature mosquitoes was
recorded after 24, 48 and 72 h exposure period continuously.
Results:Third instar larvae after 24 h exposure period, maximum mortality of 77.80% was
recorded at 250 mg/L concentration of acetone extract. After 48 h and 72 h exposure period,
maximum mortality of 88.90% was recorded in acetone extract in all the tested concentration.
The maximum mortality of fourth instar larvae was 88.90% in acetone extract at 200
and 250 mg/L concentrations. Pupal mortality was also greater in acetone extract. The
percentage of mortality in all the stage of mosquitoes was higher in acetone extract
followed by methanol and water extract.
Conclusions:The percentage of mortality is associated with concentration of the extracts tested
and exposure period. This laboratory study confirmed immature mosquitocidal activity of
Xanthium strumariumleaf extracts against Culexmosquitoes. The aqueous leaf extract can be
used by applying on small man-made breeding places to prevent adult emergence.
