Abstract:
Culex mosquito species transmit various human pathogens including encephalitis, Rift
valley fever and lymphatic filariasis. To find out eco-friendly alternatives to replace
synthetic chemical pesticides used in mosquito control program present was carried out t o
evaluate acetone, chloroform, methanolic and distilled water extracts of Argemone
mexicana seeds and leaves against IV
th
instar larvae of Culex mosquito species. The
larvicidal property of the plant extracts was tested following WHO method. Results
revealed that maximum percentage mortality of 73.3% was observed in 500 ppm
concentration after 96 hr exposure period in chloroform extract of leaves. Similar
concentration and exposure period was recorded in methanolic extract of seeds with 86.6%
mortality. The computed probit analysis results showed minimum LC50 concentration of
567.3 ppm for methanolic extract of leaves after 24 hr exposure period followed by
chloroform (407.4 ppm) extract after 48 hr exposure period and 190.1 ppm for acet one
extract after 72 hr exposure period. In seed extracts, 670.9 ppm concentration for
methanolic extract after 24 hr exposure period, 499.4 ppm concentration for acetone
extract after 48 hr exposure period and 64.3 ppm and -289.6 ppm concentration for
methanolic extract after 72 and 96 hr exposure period respectively. In general, dose and
time dependent larval mortality was observed in the study among the plant extracts tested.
These plant extracts may have toxic chemicals to kill the larvae of Culex mosquito species.
In Ethiopia, these plants are growing extensively and it can be useful to control larvae of
Culex mosquitoes in their breeding site. However, filed validation of the plant extracts,
characterization of bioactive molecules and formulations are important to utilize large
scale field application.
