Evaluation of the efficacy of three plant extracts as potent mosquito Larvicides, Pupicides, and Adulticides

Mosquitoes are the major cause of several diseases all over the world. Plants have a variety of small organic molecules which are secondary metabolites, and act as natural insecticides This study was planned to evaluate the insecticidal effect of Citrus clementina Hort. peel and whole fruits of Mimusops elengi L. and Ricinus communis L. on the larvae, pupae & adult stages of Culex quinquefasciatus. The tested plant parts were collected fresh and their efficacy was confirmed at different concentrations. The crude extract of three plant parts in different graded concentrations, i.e., 0.1, 0.2, 0.3, 0.4, 0.5 ml, 0.6 ml, 0.7 ml, 0.8 ml, 0.9 ml, and 1 ml, showed significant larval mortality at P > 0.05. 100 % larval mortality was observed at 1 ml concentration of peel extract of C. clementina followed by 93.33% (fruit extract of M. elengi) and 86.67 % (fruit extract of R. communis) against 2nd instar larvae of Cx. quinquefasciatus. The lowest LC50 value calculated was 0.30 ml, 0.21 ml, and 0.27 ml of peel extract of C. clementina and crude fruit extract of R. communis and M. elengi respectively. The crude extracts of both fruits and peel also showed pupicidal and adulticidal activity with LC50 values of 4.23 ml, 0.22 ml, and 8.44 ml; 0.21 ml, 3.98 ml, and 0.42 ml, respectively. In the laboratory, qualitative phytochemical tests are also carried out. The result of the phytochemical analysis indicates the presence of secondary metabolites such as flavonoid, phenolic compound, phlobatannin, tannins, and protein in the crude extract of the tested plant parts of three plants. Observation under a compound microscope was done to find out the potential cause of the death of mosquito larvae and pupae. From the results, it can be concluded that the crude extracts of tested plant extracts have an excellent potential to be used as an ideal eco-friendly approach to control the different life forms of Cx. quinquefasciatus.