PHYTOCHEMICAL CONSTITUENTS AND LARVICIDAL ACTIVITIES OF EUCALYPTUS CAMALDULENSIS SCHLECHT AND EUCALYPTUS TORELLIANA F. MUELL ETHANOLIC LEAF EXTRACTS AGAINST CULEX QUINQUEFASCIATUS MOSQUITO LARVAE

ABSTRACT

The leaves of Eucalyptus camaldulensis Schlecht and Eucalyptus torelliana F. Muell. were collected from the University of Benin and air-dried under shade for two weeks. The dried leaves were pulverized to fine powder and extracted using ethanol. The larvae of Culex quinquefasciatus were cultured in aquarium in the botanic garden of Department of Plant Biology and Biotechnology, University of Benin. Thirty larvae each of the mosquitoes at 4th instar were transferred into three different containers each containing 2.5 g/L, 5.0 g/L and 12.5 g/L concentrations of the dissolved ethanolic extracts and three control (0 g/L) . The larvicidal activity of the ethanolic leaf extracts of the research plants were monitored for 48 hours. The potency of the different concentrations of E. camaldulensis and E. torelliana ethanolic leaf extracts recorded within 24 hours to 48 hours period of set up of the experiment revealed that 12.5 g/L concentration of both plants gave a higher mortality of 75.53 % and 72.00 % respectively and 2.5 g/L resulted in a lower mortality of 34.43 % and 33.33 % respectively. This indicates that the degree of mortality is dependent on the concentration of the extracts. Phytochemical screening performed on the two different plants extracts revealed the presence of alkaloids, flavonoids, eugenols, glycosides, saponins, steroids, tannins and terpenoids.