Toxic effects of some botanical seed extracts against mosquito larvae Culex quinquefasciatus say (diptera: culicidae)

Culex quinquefasciatusis is responsible for biting nuisance and spreading some dreadful diseases among human beings. Hence, to protect the human in search of an alternative natural insecticide, an excellent study was designed to evaluate the larvicidal activities of Phyllanthus emblica, Carica papaya and Brassica napus seed extracts against C. quinquefasciatus Say larvae under laboratory condition. The larvicidal activity of    P. emblica seed extracts was evaluated at different concentrations of distilled water (2000-8000 ppm), methanol (1000-3000 ppm), acetone (800-1400 ppm) and 50% ethanol (2500-4500 ppm), and LC₅₀ of the four extracts were 4189.230 ppm, 1724.708 ppm,1030.483 ppm and 3354.829 ppm, respectively. In case of       C. papaya seed extract larvicidal activity was checked at concentrations of distilled water (2000-8000 ppm), methanol (700-1500 ppm), acetone (200-400 ppm) and 50% ethanol (1000-2000 ppm) and LC₅₀ were 4559.578 ppm, 1000.561 ppm, 265.929 ppm and 1406.930 ppm for the four extracts, respectively. For         B. napus seed extracts larvicidal activity was recorded at concentrations of distilled water (7000-15000 ppm), methanol (1500-3500 ppm), acetone (500-1100 ppm) and 50% ethanol (2500-4500 ppm) and LC₅₀ were 10118.017 ppm, 2146.948 ppm,700.689 ppm, and3180.144 ppm respectively. Relative position of the extracts on the basis of LC₅₀ and relative potency values was acetone > methanol > 50% ethanol > distilled water, and that of the seed was C. papaya > P emblica >B. nigrus.

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