2.6. Bioassays for larvae
Three different concentrations 0.5%, 1% and 2% of each plant aqueous extract were used for bioassays[22]. For each concentration prepared, a batch of two beakers of 100 mL was used. Two controls were run: one blank control with 100 mL of water, and one with 100 mL water supplemented with 1 mL of ethanol that was used as the positive reference. For oil extracts, 1 mL acetone was added to 100 mL of natural breeding pound water prior to adding 1 mL crude oil seed extract of each plant. Twenty-five third instar larvae of Ae. albopictus or Cx. quinquefasciatus were introduced in each beaker and kept immersed for 24 h. After incubation time-period, mortality of larvae in each beaker was recorded. Each experiment comprised a minimum number of 4 replicates. Immobile and moribund larvae were counted as dead.
2.7. Statistical analysis
The average values of mortality of mosquitoes were calculated and mortality curves were drawn on log-log graph paper to find out LC50 for each extract. Data were analysed using SPSS. 10 (Version, 2010). Mortality rates of different treatments were subjected to ANOVA (α=0.05). When ANOVA results were significant, means were separated using Tukey-Kramer test (α=0.05).