Sensitivity of Culicoides obsoletus (Meigen) (Diptera: Ceratopogonidae) to deltamethrin determined by an adapted WHO standard susceptibility test.
Bluetongue is a disease of major economic concern in Europe. Its causative agent, bluetongue virus (BTV), is transmitted by several Culicoides species (mainly Culicoides imicola and Culicoides obsoletus in Europe). The application of insecticides on animals may reduce transmission of BTV, however, no formulation is currently licensed specifically against Culicoides midges. The present study assesses the susceptibility of C. obsoletus to deltamethrin using an adapted World Health Organization (WHO) susceptibility test. Midges were exposed to different dosages of deltamethrin for 1 h, and mortality after 1 h and 24 h was recorded. Results indicated that deltamethrin is highly toxic to C. obsoletus since a dose of 1·33×10(-4)% was enough to kill 50% of the population (LD50) in 24 h. The deltamethrin concentration needed to kill 90% of the population (LD90) was 5·55×10(-4)%. The results obtained in the present work could help to create a system that can be used to assess insecticide resistance and susceptibility of Culicoides biting midges.
Laboratory of Zoology, University of the Balearic Islands (UIB), Palma de Mallorca, Spain.
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Del Río
Entente Interdépartementale pour la Démoustication du littoral méditerranéen (EID Méditerranée), Montpellier, France.
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Venail
Unit of Animal Health and Production, Centre for Agricultural Food Technology and Research [Centro de Investigación y Tecnología Agroalimentaria (CITA)], Zaragoza, Spain.
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Calvete
Laboratory of Zoology, University of the Balearic Islands (UIB), Palma de Mallorca, Spain.
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Barceló
Centre International de Recherche de l'Agriculture et du Dévéloppement (CIRAD), Montpellier, France.
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Baldet
Department of Animal Pathology, University of Zaragoza (UZ). Faculty of Veterinary Science, Zaragoza, Spain.
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Lucientes
Laboratory of Zoology, University of the Balearic Islands (UIB), Palma de Mallorca, Spain.
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Miranda
D000818:Animals; D001819:Bluetongue / Q000453:epidemiology*; D001820:Bluetongue virus / Q000502:physiology*; D002519:Ceratopogonidae / Q000187:drug effects*; D007303:Insect Vectors / Q000187:drug effects*; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D007928:Lethal Dose 50; D009570:Nitriles / Q000494:pharmacology*; D011722:Pyrethrins / Q000494:pharmacology*; D012756:Sheep; D013030:Spain / Q000453:epidemiology; D014944:World Health Organization
D007306:Insecticides; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin