Larvicidal activity of selected plant extracts and their combination against the mosquito vectors Culex quinquefasciatus and Aedes aegypti

Abstract

In order to develop an environment-friendly botanical mosquito larvicide alternative to the chemical larvicides, extracts were made from the leaves of Hyptis suaveolens, Lantana camara, Nerium oleander, and Tecoma stans with three organic solvents such as methanol (ME), chloroform (CH), and petroleum ether (PE) using a Soxhlet extractor. The plant extracts were screened for larvicidal activity individually and in combination against the larvae of Aedes aegypti and Culex quinquefasciatus as per WHO protocol. Among the extracts, the maximum larvicidal activity was shown by the PE extract of L. camara (LC 10.63 mg/L) followed by the PE extract of T. stans (LC 19.26 mg/L), ME extract of N. oleander (LC 35.82 mg/L), and PE extract of H. suaveolens (LC 38.39 mg/L) against Cx. quinquefasciatus. In the case of Ae. aegypti, the PE extract of T. stans showed maximum activity with LC value of 55.41 mg/L followed by H. suaveolens (LC 64.49 mg/L), PE extract of L. camara (LC 74.93 mg/L), and ME extract of N. oleander (LC 84.09). A blend of these four extracts resulted in a combination with corresponding LC values of 4.32 and 7.19 mg/L against Cx. quinquefasciatus and Ae. aegypti. The predator safety factors were 12.55 and 20.88 for Gambusia affinis with respect to Aedes and Culex larvae for the extract combination. Chemical constituents in extracts were also identified by FT-IR and GC-MS data. The present investigations suggest the possible use of this blend of botanical extracts as an ideal ecofriendly, larvicide against Ae. aegypti and Cx. quinquefasciatus larvae.

Evaluation of Two Different Solvents for Azolla pinnata Extracts on Chemical Compositions and Larvicidal Activity against Aedes albopictus (Diptera: Culicidae)

“…Vector control programs are requisite part of global strategy for managing mosquito-borne diseases, and commonly used insecticide applications are the most essential components for this sector [4]. In addition to that, the mosquitoes in the juvenile stages can be killed before it emerges into haematophagous adults, by the larvicidal applications [4]. Since larvae are only bound to their habitats, the control operations will be much easier with larvicides.…”

Derivatization increases mosquito larvicidal activity of the sesquiterpene lactone parthenin isolated from the invasive weed Parthenium hysterophorus

“…Compound combinations may result in synergistic, antagonistic, or no effect in biological activities. Indeed, larvicidal activity of blends of plant‐based compounds is well documented in the literature 34 . Typically, if compounds act through a common receptor pathway in a competitive manner, then a decrease or complete loss in activity is expected.…”

Subtribe Hyptidinae (Lamiaceae): A promising source of bioactive metabolites

“…Other study reported the activity of a petroleum ether extract of Mesosphaerum suaveolens (syn. Hyptis suaveolens ) against Culex quinquefasciatus (LC 50 38.39 μg/mL) and Aedes aegypti (LC 50 64.49 μg/mL) ( Hari and Mathew, 2018 ).…”