Life Expectancy and Lethal Effect of Culex Quinquefasciatus Larvae due to S-Hydroprene and Leaf Extracts of Azadirachta Indica

Abstract

Culex quinquefasciatus is a dorminant mosquito species in Nigeria and a major cause of several diseases. The study seeks to determine the effects of S-Hydroprene and leaf extracts of Azadirachta indica on life expectancy of third instar larvae of Culex quinquefasciatus. Concentrations (ranging from 10 mg/L to 60 mg/L) were tested on the larvae for mortality, survival and life expectancy of the medically important Cx. quinquefasciatus mosquito species under laboratory conditions of temperature (25̊ - 27̊), relative humidity (70% – 80%) and photoperiod (14hrs). Chloroform extract killed more larvae of Cx. quinquefasciatus at 60 mg/L (70.67%) among leaf extracts while methanol killed less (32%). S-Hydroprene showed more deleterious effect at 60 mg/L (82%). Since extracts of Az. indica had less toxic effect, they allowed for the survival of Cx. quinquefasciatus and extended the larval period. S-Hydroprene and the leaf extracts of Azadirachta indica are capable of increasing life expectancy of Culex quinquefasciatus larvae at certain concentrations until they all died out or a few adults emerge. To control Culex quinquefasciatus therefore, extracts of Azadirachta indica can be used to reduce the number of adult emergence in our environment and in turn reduce their rate of disease transmission.

Keywords:  Mortality, Life expectancy, Azadirachta indica, Culex quinquefasciastus, Insect Growth Regulators, larvicidal, S-Hydroprene