Phytocompounds for mosquito larvicidal activity and their modes of action: A review

Mosquitoes (Diptera: Culicidae) act as vectors of a wide variety of human and veterinary pathogens and para-sites. In controlling mosquito population, the use of compounds from plants is considered advantageous; they are target-specific and biodegradable. These secondary metabolites are referred to as green pesticides as they are reported to be efficient and safe for other vertebrates. The activity of the phytocompounds against mosquito larvae varies significantly depending on several factors such as the species, plant parts used, age (young or old), mature or senescent and solvent used during extraction. Different secondary metabolites from plants have different potentials which affect insect behavior, repel the pest, disrupt feeding activity, affect pest physiology, inhibit respiration and growth, reduce fecundity and disrupt cuticle formation. This review provides a critical analysis of plant chemicals with mosquito larvicidal efficacy and their mode of action, which have been reported for the past 10 years. Several online databases including PubMed, Scifinder, Google Scholar and Web of Science were used in searching for information on mosquito larvicidal metabo-lites from plants. A total of 180 compounds from 97 plant species having larvicidal activity was recorded. Among these, only 26 compounds presented larvicidal activity <1parts per million (ppm) against larvae of the mosquito species of health importance. Compounds such as methyl palmitate, proanthocyanidins, 22-monacetonide, and 20-hydroxyecdysone recorded 100% larvicidal activity against An. gambiae and Ae. aegypti. A total of 91 compounds showed larvicidal activity against different mosquito species at 1-25 ppm concentrations. Generally, the insecticides with toxicity were reported to interfere with nerve functions, physiology, development and as well hamper the insect's day-to-day activities. Currently, the research on the mode of action of biomolecules from plants is scarce. In future, the researchers should study the mode of action of these larvicides. (c) 2022 SAAB. Published by Elsevier B.V. All rights reserved.

Automated summary

Mosquitoes act as vectors for various diseases and parasites, and plant compounds are considered advantageous for controlling mosquito populations due to their target specificity and biodegradability. This review critically analyzes plant chemicals with larvicidal efficacy against mosquitoes and discusses their mode of action.