title: Acute larvicidal toxicity of five essential oils (Pinus nigra, Hyssopus officinalis, Satureja montana, Aloysia citrodora and Pelargonium graveolens) against the filariasis vector Culex quinquefasciatus: Synergistic and antagonistic effects.
abstract: Mosquito vector control is facing a number of important and timely challenges, mainly due to the rapid development of pesticide resistance and environmental concerns. In this scenario, screening of botanical resources for their mosquitocidal activity may offer effective and eco-friendly tools against Culicidae vectors. Culex quinquefasciatus Say (Diptera: Culicidae) is a vector of lymphatic filariasis and of dangerous arboviral diseases, such as West Nile and St. Louis encephalitis. In this study, the chemical composition of five essential oils obtained from different plants, namely Pinus nigra J.F. Arnold var. italica (Pinaceae), Hyssopus officinalis L. subsp. aristatus (Lamiaceae), Satureja montana L. subsp. montana (Lamiaceae), Aloysia citriodora Palau (Verbenaceae) and Pelargonium graveolens L'Hér (Geraniaceae), was investigated by GC-MS analysis. Furthermore, it was evaluated their acute toxicity on larvae of C. quinquefasciatus. Then, the most effective oils were selected, in order to focus on the potential synergistic and antagonistic effects, testing them in binary mixtures on C. quinquefasciatus larvae. Results showed that the higher effectiveness was obtained by S. montana subsp. montana essential oil (LC50=25.6μL·L-1), followed by P. nigra var. italica (LC50=49.8μL·L-1) and A. citriodora (LC50=65.6μL·L-1), while the other essential oils showed LC50values higher than 90μL·L-1. The larvicidal effectiveness can be enhanced by preparing simple binary mixtures of essential oils, such as S. montana+A. citriodora (ratio 1:1), which showed higher larvicidal toxicity (LC50=18.3μL·L-1). On the other hand, testing S. montana+P. nigra (1:1) an antagonistic effect was detected, leading to a LC50(72.5μL·L-1) higher than the LC50values calculated for the two oils tested separately. Overall, our results add useful knowledge to allow the employ of synergistic essential oil blends as effective, cheap and eco-friendly mosquito larvicides.
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy. Electronic address: benelli.giovanni@gmail.com.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Benelli
authors.affiliation: Crop Research Institute, Drnovska 507, 161 06 Prague 6, Czech Republic.
authors.forename: Roman
authors.initials: R
authors.lastname: Pavela
authors.affiliation: Department of Agriculture, Food and Environment, University of Pisa, via del Borghetto 80, 56124 Pisa, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Canale
authors.affiliation: Géoarchitecture, UFR Sciences & Techniques, Université de Bretagne Occidentale, Brest, France; School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy.
authors.forename: Kevin
authors.initials: K
authors.lastname: Cianfaglione
authors.affiliation: Majella National Park, Sulmona, Italy.
authors.forename: Giampiero
authors.initials: G
authors.lastname: Ciaschetti
authors.affiliation: School of Bioscience and Veterinary Medicine, University of Camerino, Centro Ricerche Floristiche dell'Appennino, San Colombo, Barisciano, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Conti
authors.affiliation: Department of Environmental Biology, Sapienza University, Rome, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Nicoletti
authors.affiliation: Division of Biopesticides and Environmental Toxicology, Sri Paramakalyani Centre for Excellence in Environmental Sciences, Manonmaniam Sundaranar University, Alwarkurichi, 627 412 Tirunelveli, Tamil Nadu, India.
authors.forename: Sengottayan
authors.initials: S
authors.lastname: Senthil-Nathan
authors.affiliation: Department of Parasitology, Heinrich Heine University, Düsseldorf, Germany.
authors.forename: Heinz
authors.initials: H
authors.lastname: Mehlhorn
authors.affiliation: School of Pharmacy, University of Camerino, Camerino, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Maggi
mesh_terms: D000818:Animals; D003465:Culex / Q000187:drug effects*; D004336:Drug Antagonism; D004357:Drug Synergism; D004605:Elephantiasis, Filarial / Q000517:prevention & control / Q000635:transmission; D004674:Encephalitis, St. Louis / Q000517:prevention & control / Q000635:transmission; D008401:Gas Chromatography-Mass Spectrometry; D000068819:Hyssopus Plant / Q000737:chemistry; D007306:Insecticides / Q000737:chemistry / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects; D000072138:Mosquito Vectors / Q000187:drug effects*; D009822:Oils, Volatile / Q000737:chemistry / Q000494:pharmacology*; D031316:Pelargonium / Q000737:chemistry; D028223:Pinus / Q000737:chemistry; D018515:Plant Leaves / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*; D031362:Satureja / Q000737:chemistry; D029648:Verbenaceae / Q000737:chemistry; D014901:West Nile Fever / Q000517:prevention & control / Q000635:transmission
chemical_list: D007306:Insecticides; D009822:Oils, Volatile; D010938:Plant Oils
keywords: Culicidae; Essential oils; Green pesticides; Integrated Vector Management; Mosquito control; St. Louis encephalitis; West Nile