Larvicidal potency of selected xerophytic plant extracts on Culex pipiens (Diptera: Culicidae)

Journal Article

2018

Chemical insecticides released into the environment may have adverse biological

effects. Therefore, there is a need for ecofriendly insecticides for mosquito control.

Xerophytic plant extracts that may provide more ecofriendly active component were

evaluated against Culex pipiens 4th instars. Plant extracts prepared using different

solvents with a Soxhlet apparatus and different concentrations were tested against

Culex pipiens larvae. The effects were observed at 24 h and 72 h intervals and LD50

and LD90 values determined. Chloroform (CHCl3) and ethyl acetate (EtOAc) extracts

of Althaea ludwigii were the most effective against Cx. pipiens 4th instars, but were

highly dependent on extract concentrations and exposure time. Results suggest that

A. ludwigii extracts contain bioactive compounds, such as phenols and saponins, that

may provide effective Cx. pipiens larval control. However, the extract was found to be

toxic to zebrafish larvae, and may be toxic to other aquatic fauna. Further studies to

determine the active components and toxicity to other fauna are needed.