Article
High larvicidal efcacy of yeast-encapsulated orange oil against Aedes aegypti strains from Brazil
Registro en:
GOMES, Bruno et al. High larvicidal efcacy of yeast-encapsulated orange oil against Aedes aegypti strains from Brazil. Parasites & Vectors, v. 14, n. 272, 11 p, 2021.
1756-3305
10.1186/s13071-021-04733-2
Autor
Gomes, Bruno
Ogélio, Huarlen
Brant, Fabiane
Pinto, Camila Jesus Pereira
Workman, Michael J.
Costa, Monique
Kima, José Bento Pereira
Martins, Ademir Jesus
Ortigão, Marcelo Ramalho
Durvasula, Ravi
Hurwitz, Ivy
David, Mariana Rocha
Genta, Fernando Ariel
Resumen
Background: Botanical substances such as essential oils (EOs) have demonstrated insecticidal properties and are a
valid option for vector control. However, free EOs are unreliable as mosquito larvicides due their easy degradation by
environmental exposure to ultraviolet light and higher temperatures. Here, we assessed the efcacy of a mosquito
larvicide based on orange oil in a yeast-based delivery system against Aedes aegypti strains with diferent resistance
status towards chemical neurotoxic insecticides. This larvicide preparation was physicochemically characterized in a
previous report.
Methods: Larvae of four Ae. aegypti strains from diferent regions of Brazil and diferent resistance profles for del‑
tamethrin (pyrethroid) and temephos (organophosphate) were tested against yeast-encapsulated orange oil (YEOO)
in laboratory conditions for measurement of LC50 and LC90 values. The same assays were performed with the Belo
Horizonte strain under environmental conditions (natural light and temperature). The resistance profles of these
strains were compared to the Rockefeller reference strain in all conditions.
Results: YEOO was found to be a highly active larvicide (LC50<50 mg/L) against all Ae. aegypti strains tested in both
laboratory conditions (LC50=8.1–24.7 mg/L) and environmental conditions with natural light and temperature
fuctuation (LC50=20.0–49.9 mg/L). Moreover, all strains were considered susceptible (RR<5) to YEOO, consider‑
ing resistance ratios calculated based on the Rockefeller strain. The resistance ratios were only higher than 2.5 for
LC90–95 of Belo Horizonte in the laboratory, probably due the higher heterogeneity associated with older egg papers
(>5 months).
Conclusion: YEOO demonstrates high larvicidal activity against Ae. aegypti strains with resistant phenotypes for
deltamethrin (PY) and temephos (OP). This larvicidal activity suggests the potential for the development of YEOO as
an alternative intervention to synthetic insecticides in integrated vector management programs, for populations with
resistance to commonly used insecticides.