To investigate the mosquitocidal activities of Nepta cataria essential oil against Aedes aegypti, Anopleles stephensi and Culex quinquefasciatus. Twenty five early third instar larvae of selected mosquitoes were exposed to various concentrations (30- 150ppm) and were assayed in the laboratory by using the protocol of WHO 2005; the 24h LC50 values of the essential oil was determined by probit analysis. The ovicidal activity was determined against Aedes aegypti, Anopheles stephensi and Culex quinquefasciatus exposed to various concentrations were tested under laboratory conditions and the hatch rates were assessed 48hrs post treatment. Similarly, selected essential oil were tested against pupae of selected mosquitoes at various concentrations and mortality of each pupa was recorded after 2days post treatments of exposure. Repellent activity was carried out in a net cage (45×30×45 cm2) containing 100 blood starved female selected mosquitoes and were assayed in the laboratory condition by using the protocol of WHO 1996; The essential oil of Nepta cataria was applied at 2.0, 4.0 and 6.0 mg/cm2 separately in the exposed area of the fore arm. LC50 and LC90 values of Nepta cataria essential oil on Ae. aegypti, An. stephensi and Cx. quinquefasciatus larvae in 24 h were 67.53, 73.09, 78.62 and 130.61, 145.24 and 152.77 ppm respectively. The data is statistically significant at P < 0.05. It has been noticed that the higher concentrations of Nepta cataria essential oil possesses strong ovicidal activity at 300ppm concentration against Ae. aegypti, An. stephensi and C. quinquefasciatus, were 84.46%, 94.33% and 96.54%, respectively. In pupicidal activity, among the three mosquito tested against Nepta cataria essential oil at 300ppm higher concentrations, the C. quinquefasciatus was found to be most effective for pupicidal activity provided 96.25% and Ae. aegypti and An. stephensi were85.61% and 92.87%, respectively. The repellent activity of Nepta cataria essential oil was found to be most effective for repellent activity against Ae. aegypti followed by An. stephensi and Cx. quinquefasciatus and a higher concentration of 6mg/cm2 provide100% protection up to 210, 180 and 150 min against Ae. aegypti, An. stephensi and Cx. quinquefasciatus, respectively. From the results it can be concluded the essential oil of Nepta cataria as an excellent potential agent for controlling selected mosquitoes species.
