Fumigant toxicity and phytochemical analysis of Petiveria alliacea (Linneaus) leaf and root bark oil on adult Culex quinquefasciatus
Bulletin of the National Research Centre
Culex mosquitoes are a major vector of public health importance and have been implicated for the transmission of some parasitic diseases such as lymphatic filariasis and West Nile virus. It has also been reported to cause several problems which include developing resistance to synthetic insecticides, thus, necessitating the search for an insecticide of botanical origin which is bio-degradable, non-toxic, and readily available for man's use. This study aimed to evaluate the phytochemicals
... ytochemicals present in Petiveria alliacea and the fumigant efficacy of its oil extract against the adult stage of Culex quinquefasciatus. Results: The result obtained shows that the oil extract of Petiveria alliacea at all concentrations had a significant effect on the adult mosquito for fumigant toxicity with percentage mortality range of 75.00-100% within a 2-h exposure period (P < 0.05) for the leaf extract and 81.67-100% mortality for the root bark extract. The synergistic effect of the leaf and root bark oil was also investigated. The lethal concentration (LC 50 ) of the leaf, root, and synergistic effect of leaf and root oil extract required to kill 50% of the adult Culex quinquefasciatus was 0.45 ml, 0.53 ml, and 0.47 ml, respectively. However, 2.20 ml, 1.194 ml, and 1.15 ml of the leaf, root, and leaf and root oil extract were required to kill 90% (LC 90 ) after a 2-h exposure period. A total of 29 organic compounds were isolated from leaf and root bark oil of the plant. The study has revealed that the leaves and root bark of Petiveria alliacea are rich in phytochemicals Conclusion: These findings suggested Petiveria alliacea oil extract could be a good source of insecticide which may be used for the production of biopesticides. The present findings have important implications in the practical control of adult mosquito by using botanical insecticides. These plant extracts are easy to prepare, inexpensive, and safe for mosquito control which possesses enough insecticidal potential and can be used directly around human dwellings. The result suggests possible utilization of the cheap and readily available botanicals for possible control of mosquitoes as part of an integrated vector management programme.