Evaluating Natural Larvicides: Peppermint and Pepper Extracts versus Temephos on Aedes aegypti and Anopheles stephensi Larvae Under Laboratory Conditions.

BACKGROUND

Anopheles stephensi is an important vector for malaria, while Aedes aegypti transmits dengue, chikungunya, Zika, and yellow fever. With the increasing replacement of natural insecticides for conventional ones, it is essential to investigate mosquito resistance to these insecticides and assess the larvicidal potential of new alternatives and their comparison to standard larvicides like temephos.

METHODS

The alcoholic extracts of Mentha piperita and Capsicum annuum were prepared using the maceration method. Mosquitoes were bred at the Bandar Abbas research station in 2024. Biometric tests were performed following the World Health Organization protocol, and the data were analyzed using SPSS version 27 and GraphPad Prism 10.

RESULTS

The lethal concentration 50% (LC50) of M. piperita extract was 4.047 ppm against An. stephensi larvae and 9.9 ppm against Ae. aegypti larvae. Similarly, the LC50 of C. annuum extract was 5.872 ppm for An. stephensi larvae and 11.752 ppm for Ae. aegypti larvae. The larvicidal values of temephos were found to be 0.003 ppm against An. stephensi larvae and 0.002 ppm against Ae. aegypti larvae.

CONCLUSION

Mentha piperita and C. annuum extracts possess measurable larvicidal activity against An. stephensi and Ae. aegypti. However, their effectiveness remains substantially lower than that of temephos. These findings should be considered preliminary evidence rather than an indication of operational readiness. These extracts may represent a promising starting point for future research, but further studies on formulation, environmental persistence, non-target impacts, and field performance are required before use for management programs.