Larvicidal activity of Zataria multiflora, Eucalyptus caesiaBenth and Menthapiperitaessential oils against Culex.

Mosquito is a vector of several life threatening diseases affecting humans. The use of synthetic insecticides in the vector control is not advisable due to concern about environmental sustainability, harmful effect on human health and increasing insecticide resistance. So, the objective of this study was to assess larvicidal activity of essential oils (EOs) of Zataria multiflora, Eucalyptus caesia Benth, and Mentha piperita against the Culex mosquito.

The larvicidal activity of the essential oils were tested according to the WHO procedure. The larvae exposed to three-fold serial dilution of oils (2.5-400 ppm) using a dipping method for 24 h and then simultaneously each replicate was incubated in separate petri dishes at 27°C and 80-90% relative humidity. Mortality rate was recorded after an exposure of 24 h. LC50 and LC90 were calculated using Probit analysis and all data were analyzed using ANOVA and post hoc Tukey test.

In the comparative analysis of the essential oils, LC50 & LC90 of Z. multiflora, E. caesia Benth and M. piperita were5.09429 and26.9919, 3.66376 and 35.3173, and 8.3115 and 218.888 ppm, respectively. Also, as the concentration of essential oil increased, mortality rate of larvae increased too.

This study concluded that the essential oils of Z. multiflora, E. caesia Benth and M. piperita have appropriate larvicidal activity against Culex, therefore, they can be used as good alternative to the Culex biological control.