Medicinal plants show promise in killing mosquito larvae: Study

Researchers from the Department of Botany at Chittagong University have found that extracts from common medicinal plants can be highly effective in killing mosquito larvae.

This research, led by Associate Professor Mohammad Omar Faruque Russell, offers a potentially safer and more eco-friendly alternative to chemical insecticides, which are often limited by mosquito resistance and harmful to the environment.

The three-year study investigated the potential of extracts from a staggering 250 plant parts, representing 77 different genera. These extracts targeted the larvae of Aedes, Culex, and Anopheles mosquitoes, known transmitters of diseases like dengue, malaria, Zika, and chikungunya.

The results were impressive. Researchers observed significant larvicidal activity (killing mosquito larvae) in extracts from 55 plants.

Notably, 19 plants achieved a perfect 100% kill rate within hours, including Rauvolfia vomitoria, Spilanthes acmella (commonly known as the toothache plant), and Black pepper (Piper nigrum).

Several other plant extracts showed exceptional promise, with kill rates between 99% and 80%. These included Asclepias curassavica (milkweed) and Neem (Azadirachta indica), a plant already recognised for its medicinal properties.

The research team is optimistic that these findings can pave the way for a new generation of mosquito control methods. Their next steps involve isolating the specific insecticidal compounds within these plants and evaluating their effectiveness in real-world settings.

Associate Prof Omar emphasises the potential of this research to revolutionise mosquito control strategies, not just in Bangladesh but globally. 

He envisions the development of plant-based larvicides as a sustainable and long-term solution to combat mosquito-borne diseases and protect public health.

This discovery builds upon a 2021 collaboration between the University of Chittagong and Chattogram City Corporation that highlighted the shortcomings of current chemical insecticides used in the city. 

The 2021 study revealed low mosquito mortality rates after applying commercially available adulticides and larvicides.

The new research on plant-based larvicides offers significant hope for overcoming the limitations of chemical insecticides. This approach has the potential to create a more sustainable and effective strategy for controlling mosquito populations, ultimately safeguarding public health from mosquito-borne diseases.

While the initial findings are promising, Associate Prof Omar acknowledges the need for further research. Isolating the active insecticidal compounds and conducting field trials are crucial steps before widespread application.

Additionally, collaboration with government organisations and public health agencies will be essential for developing and implementing these plant-based larvicide solutions.