EVALUATION OF LARVICIDAL PROPERTIES OF ARGEMONE MEXICANA LINN. SEED AND LEAF EXTRACTS AGAINST CULEX MOSQUITO (DIPTERA: CULICIDAE) SPECIES

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.