Bioefficacy of citrullus colocynthis (l.) schrad (cucurbitaceae) whole plant extracts against anopheles stephensi, aedes aegypti and culex quinquefasciatus (diptera: culicidae)

The whole plant crude extracts of Citrullus colocynthis were evaluated for larvicidal, pupal deformities and adult emergence inhibition activity against vector mosquitoes viz., Anopheles stephensi, Aedes aegypti, and Culex quinquefasciatus. Dichloromethane extract was found to be effective against Culex quinquefascaitus (LC50 value of 240.36 ppm) larvae. Larval and pupal development was arrested resulting in decreased pupal transformation and adult emergence. Larval and pupal periods were prolonged with appearance of larval–pupal and pupal–adult intermediates, with an overall increase in the developmental period with respect to all three vector mosquito species. Adult emergence inhibition activity was more pronounced in Anopheles stepehensi. Hatching was delayed and its rate was reduced when compared to control and significant ovicidal activity was observed in the eggs of Anopheles stephensi. Disrupted egg shells and dechitinized body walls were observed, indicating the anti-juvenile potential of the plant extract. The growth index was considerably reduced. These results suggest the extracts of Citrullus colocynthis as a promising adult emergence inhibitor against vector mosquitoes and might be used in small volume aquatic habitats or breeding sites of limited size in and around human dwellings.