Assessment of larvicidal, growth-suppressing, and development-altering bioefficacy of Ageratum houstonianum against Aedes aegypti (L.).

BACKGROUND

OBJECTIVES

Aedes aegypti is a major vector responsible for spreading dengue, chikungunya, yellow fever, and Zika viruses worldwide. These illnesses have increased globally due to climate and environmental changes. Vector control and management are the principal tactics for combating mosquitoes-borne diseases in the absence of an effective vaccine. The study aimed to ascertain bioactivities of Ageratum houstonianum leaf acetone extract ( Ah LAE) against Ae. aegypti .

METHODS

Bioefficacy of Ah LAE was tested against fourth instar larvae (L4) of Ae. aegypti using standard WHO protocol. The mortality, growth, and development of larvae, pupae and adults were recorded after exposure to the extract.

RESULTS

The Ah LAE showed larvicidal activity against L4 with LC 50 and LC 90 values of 401.88 and 691.24 mg/L, respectively. The mortality of the larvae further increased on subsequent days. The Ah LAE caused a significant reduction in pupae formation and adult emergence. It also increased the larval duration of L4 and development duration of the pupa formed from the treated L4, indicating its growth-suppressing effects. The impact of the Ah LAE was dose-dependent; high concentrations caused reduction in survival and growth of L4. Consequently, the L4-pupal and L4-adult growth indexes decreased. Additionally, the Ah LAE induced developmental anomalies in the form of larva-pupa (L-P) intermediates.

INTERPRETATION

CONCLUSION

The study found that the Ah LAE exhibited larvicidal, growth-suppressing, and development-altering activities against Ae. aegypti . The findings suggest the potential of AhALE as a natural insecticidal agent for controlling mosquitoes.