[Dengue vector control using ether fractions from two plants (Asteraceae) as larvicide]

Area of Science:

• Phytochemistry
• Entomology
• Toxicology

Background:

• Aedes aegypti mosquitoes are significant vectors of diseases like dengue and Zika.
• Developing effective and environmentally friendly larvicides is crucial for mosquito control strategies.
• Asteraceae family plants are known for their diverse phytochemical compounds with potential biological activities.

Purpose of the Study:

• To evaluate the larvicidal potential of ether fractions from Heliopsis oppositifolia and Jaegeria hirta against Aedes aegypti larvae.
• To determine the lethal concentrations (LC50, LC90, LC95) of these plant extracts.
• To develop a mathematical model for predicting the population dynamics of mosquito larvae based on lethal concentrations.

Main Methods:

• Phytochemical analysis of H. oppositifolia and J. hirta.
• Preparation of ether fractions from both plant species.
• Assessment of larvicidal activity at 11 different concentrations over 24 and 48 hours.
• Statistical analysis using factorial ANOVA and development of a mathematical simulation model.

Main Results:

• Phytochemical analysis revealed the presence of tannins, flavonoids, alkaloids, and other compounds in both species.
• Jaegeria hirta exhibited lower lethal concentrations (LC50: 24 ppm, LC90: 70 ppm, LC95: 93 ppm at 48h) compared to Heliopsis oppositifolia (LC50: 39 ppm, LC90: 77 ppm, LC95: 94 ppm at 48h).
• A mathematical model indicated that strategic application of LC50, LC90, and LC95 concentrations could effectively manage Aedes aegypti larval populations.

Conclusions:

• Both H. oppositifolia and J. hirta possess significant larvicidal properties against Aedes aegypti.
• Jaegeria hirta shows more promise as a natural bioinsecticide for controlling immature Aedes aegypti.
• Further research into J. hirta could lead to novel, eco-friendly mosquito control agents.