Larvicidal effect of essential oils from Brazilian cultivars of guava on Aedes aegypti L.

The mosquito Aedes aegypti L. is one of the largest vectors of human pathogens, including the dengue and chikungunya viruses. However, its control is challenging. Synthetic insecticides are one of the most used methods of vector control, but their use raises a series of environmental issues. Therefore, the application of natural products constitutes an alternative practice, as they can be effective, easily biodegradable and inexpensive. The essential oil obtained from leaves of guava (Psidium guajava L.) has shown promising larvicidal activity against A. aegypti. However, the existence of different essential oil chemotypes in this species makes it necessary to study the influence of such variation on the larvicidal activity. In the present work, the essential oils from the guava cultivars SEC, C4, C6, PAL and PET were evaluated for larvicidal effect on A. aegypti. The oils were found to be efficient, with LC50 ranging from 39.48 to 64.25 μg mL^−1. SEC was the most promising cultivar, with lowest LC50 and one of the highest extraction yields among the cultivars (0.35%). The chromatographic profile of the essential oils evidenced mainly sesquiterpenes; hence, this group of compounds may be responsible for the larvicidal effect. Besides constituting a larvicide alternative, the use of essential oils could also create new income sources for guava producers, since a large amount of plant matter is generated as a result of successive prunings