# Larvicidal and Ovicidal Effects of Methanol Extracts From Selected Ethiopian Medicinal Plants Against Anopheles arabiensis and Aedes aegypti

## TL;DR

This study tests Ethiopian medicinal plant extracts for their ability to kill mosquito larvae and eggs, offering a natural alternative to harmful insecticides.

## Contribution

The study identifies three Ethiopian plant species with strong larvicidal and ovicidal effects against two mosquito species.

## Key findings

- Millettia ferruginea showed high larvicidal activity and egg hatching inhibition against Anopheles arabiensis.
- Securidaca longepedunculata demonstrated significant larvicidal and ovicidal effects against Aedes aegypti.
- Momordica foetida caused high mortality in Anopheles arabiensis larvae at high concentrations.

## Abstract

Synthetic insecticides face challenges, such as resistance, environmental damage, and harm to nontarget species, highlighting the need for alternative methods. Medicinal plants, along with their bioactive compounds, offer a promising solution.

This study investigated the efficacy of methanol extracts derived from traditionally used Ethiopian medicinal plants against Anopheles arabiensis and Aedes aegypti.

Methanol extracts (80%) of the crude plant extracts were tested on the larvae and eggs of both mosquito species at concentrations ranging from 250 to 2000 ppm. Larval mortality was recorded after 24 h of exposure, while egg hatchability was assessed after 72 h.

Millettia ferruginea exhibited the highest larvicidal activity against Anopheles arabiensis (LC50 = 461.7 ppm, LC90 = 1746.8 ppm), achieving 90% inhibition of egg hatching at 2000 ppm. Momordica foetida resulted in 85% mortality in second‐instar larvae and 80% mortality in early fourth‐instar larvae of Anopheles arabiensis at 2000 ppm. Securidaca longepedunculata demonstrated 87% larval mortality and 92% egg hatching inhibition in Aedes aegypti at 2000 ppm. ANOVA result shows that mortality rates varied significantly across concentrations (p < 0.05)

Millettia ferruginea, Momordica foetida, and Securidaca longepedunculata are promising botanical insecticides. Future studies should focus on isolating active compounds to ensure environmental safety and effectiveness. These findings highlight the potential of indigenous plants for insect management and underscore the importance of traditional knowledge in the development of novel insecticides.