Larvicidal effect of some traditional Saudi Arabian herbs against Aedes aegypti larvae, a vector of dengue fever

Mosquitoes are effective disease vectors for human and veterinary health because they share a close environment with humans and represent a major public health problem. Saudi Arabia is home to the endemic dengue fever disease, carried by the Aedes aegypti mosquito. Conventional insecticides based on organophosphates and insect growth regulators are the most effective short-term control methods for this vector. However, these insecticides are toxic to non-target organisms, the environment, and humans. This study, eight plant extracts (Ilex paraguariensis, Camellia sinensis, Cinnamomum zeylanicum, Elettaria cardamomum, Matricaria chamomilla, Allium sativum, Coffea arabica, and Piper nigrum) were assayed as an insecticide against the 3rd and 4th larval stage of Ae. aegypti (L.), after 24 and 48 h of exposure in the duration between March and June 2023. After 48h, all plants extracted showed the highest mortality (100%), except for C. arabica which showed the lowest mortality rate (98.33%) at 30%. I. paraguariensis showed the greatest effectiveness with an LC50 =7.17 ppm, followed by P. nigrum with an LC50 = 5.66 ppm. Further investigation is needed to purify the active ingredients responsible for their toxicity to mosquito larvae and to investigate the mechanisms of action of plant extracts in water and other solvents.