title: Droplet size and efficacy of an adulticide-larvicide ultralow-volume formulation on Aedes aegypti using different solvents and spray application methods.
abstract: BACKGROUND
  When cases of dengue are reported or the density of adult Aedes aegypti (L.) becomes too high, ultralow-volume (ULV) application of insecticides is the recommended control method. The droplet size of an aerosol insecticide influences its efficiency in killing adult mosquitoes. Many studies have been carried out to determine the optimum droplet size that maximises vector control efforts, but only a few have determined droplet-size spectra for specific equipment using different solvents and comparing thermal and non-thermal aerosols.
  
  
  RESULTS
  The present study showed that the droplet size for a water-based adulticide-larvicide formulation was larger than for the same formulation diluted in gasoil or biodiesel. No significant differences in adult mortality were observed between sprayers and solvents, but efficacy decreased with distance from the sprayer nozzle. Adult emergence inhibition was more than 90% when using water as a solvent for both thermal and cold foggers, and the efficacy did not decrease with distance from the sprayer nozzle. On the other hand, oil-based solvents became less effective with distance.
  
  
  CONCLUSIONS
  The use of water as a solvent with both thermal and cold foggers improves the efficacy of the studied formulation containing permethrin as adulticide and pyriproxyfen as larvicide in scaled-up assays. Moreover, it reduces the environmental impact and costs of spraying by comparison with formulations using oil solvents.
authors.affiliation: Centro de Investigaciones de Plagas e Insecticidas (CIPEIN-CITEFA/CONICET), Villa Martelli, Buenos Aires, Argentina.
authors.forename: Laura
authors.initials: L
authors.lastname: Harburguer
authors.forename: Emilia
authors.initials: E
authors.lastname: Seccacini
authors.forename: Susana
authors.initials: S
authors.lastname: Licastro
authors.forename: Eduardo
authors.initials: E
authors.lastname: Zerba
authors.forename: Héctor
authors.initials: H
authors.lastname: Masuh
mesh_terms: D000330:Aedes / Q000187:drug effects* / Q000254:growth & development; D000818:Animals; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D007306:Insecticides / Q000737:chemistry* / Q000633:toxicity*; D007814:Larva / Q000187:drug effects* / Q000254:growth & development; D009032:Mosquito Control / Q000295:instrumentation / Q000379:methods*; D026023:Permethrin / Q000737:chemistry / Q000633:toxicity; D011725:Pyridines / Q000737:chemistry / Q000633:toxicity
chemical_list: D007306:Insecticides; D011725:Pyridines; C055613:pyriproxyfen; D026023:Permethrin