Assessment of Resistance to Organophosphates and Pyrethroids in Aedes aegypti (Diptera: Culicidae): Do Synergists Affect Mortality?

J Med Entomol. 2020 Nov 13;57(6):1992-1996. doi: 10.1093/jme/tjaa101.

Abstract

Aedes aegypti (L.) is the primary vector of Zika, dengue, yellow fever, and chikungunya viruses. Insecticides used in mosquito control can help prevent the spread of vector-borne diseases. However, it is essential to determine insecticide resistance (IR) status before control measures are undertaken. Only the most effective insecticides should be used to avoid ineffective control and/or promotion of IR. Pyrethroids and organophosphates are the most commonly used insecticides for mosquito control. Here, the efficacy of two active ingredients (AIs; permethrin [pyrethroid], chlorpyrifos [organophosphate]), two formulated products (FPs; Biomist [AI: permethrin]) and (Mosquitomist [AI: chlorpyrifos]), and three synergists (piperonyl butoxide, diethyl maleate, S-S-S-tributyl phosphorotrithioate) was evaluated in two Ae. aegypti colonies (pyrethroid resistant and susceptible). Mosquitomist was most effective against the pyrethroid-resistant colony (100% mortality at diagnostic time). Pre-exposure to synergists did not increase the efficacy of AIs against the pyrethroid-resistant colony. Further research is needed to discover how synergists may affect the efficacy of insecticides when used on pyrethroid-resistant mosquitoes.

Keywords: Ae aegypti; Biomist; Mosquitomist; organophosphate; pyrethroid.

MeSH terms

  • Aedes / drug effects*
  • Aedes / physiology
  • Animals
  • Chlorpyrifos / pharmacology
  • Female
  • Insecticide Resistance*
  • Insecticides / pharmacology*
  • Longevity
  • Maleates / pharmacology*
  • Organothiophosphates / pharmacology*
  • Permethrin / pharmacology
  • Pesticide Synergists / pharmacology*
  • Piperonyl Butoxide / pharmacology*

Substances

  • Insecticides
  • Maleates
  • Organothiophosphates
  • Pesticide Synergists
  • Permethrin
  • butyl phosphorotrithioate
  • diethyl maleate
  • Chlorpyrifos
  • Piperonyl Butoxide