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United States Department of Agriculture

Agricultural Research Service

Research Project: BITING ARTHROPODS: INTEGRATED PEST MANAGEMENT

Location: Mosquito and Fly Research Unit

Title: Insecticide resistance status of United States populations of Aedes albopictus and mechanisms involved

Authors
item Marcombe, Sebastien -
item Farajollahi, Ary -
item Healy, Sean -
item Clark, Gary
item Fonseca, Dina -

Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 12, 2014
Publication Date: July 11, 2014
Repository URL: http://doi:10.1371/journal.pone.0101992
Citation: Marcombe, S., Farajollahi, A., Healy, S.P., Clark, G.G., Fonseca, D.M. 2014. Insecticide resistance status of United States populations of Aedes albopictus and mechanisms involved. PLoS One. 9(7):e101992.

Interpretive Summary: Aedes albopictus (Skuse), the Asian tiger mosquito, is an invasive that has become an important vector of chikungunya and dengue viruses. Immature Ae. albopictus thrive in backyard household containers that require treatment with larvicides and when adult populations reach pest levels or disease transmission is ongoing, adulticiding is often required. To assess the feasibility of control of USA populations, we characterized a susceptible reference strain of the species, ATM95, and examined the prevalence of insecticide resistance to chemicals representing the main insecticide classes with different modes of action. We found that USA populations are broadly susceptible to currently available larvicides and adulticides but found populations in Florida resistant to DDT and organophosphates and pervasive reduced susceptibility to the insect growth regulators. All populations tested were fully susceptible to pyrethroids. The observed DDT resistance in populations from Florida may indicate multiple introductions of this species into the USA, possibly from tropical populations. In addition, the mechanisms underlying DDT resistance often result in pyrethroid resistance, which would undermine a remaining tool for the control of Ae. albopictus. Continued monitoring of the insecticide resistance status of this species is imperative.

Technical Abstract: Aedes albopictus (Skuse) is an invasive mosquito that has become an important vector of chikungunya and dengue viruses. Immature Ae. albopictus thrive in backyard household containers that require treatment with larvicides and when adult populations reach pest levels or disease transmission is ongoing, adulticiding is often required. To assess the feasibility of control of USA populations, we tested the susceptibility of Ae. albopictus to chemicals representing the main insecticide classes with different modes of action: organochlorines, organophosphates, carbamates, pyrethroids, insect growth regulators (IGR), naturalytes, and biolarvicides. We characterized a susceptible reference strain of Ae. albopictus, ATM95, and tested the susceptibility of eight USA populations to five adulticides and six larvicides. We found that USA populations are broadly susceptible to currently available larvicides and adulticides. Unexpectedly, however, we found significant resistance to dichlorodiphenyltrichloroethane (DDT) in two Florida populations and in a New Jersey population. We also found moderate levels of resistance to malathion, an organophosphate, in Florida and New Jersey and reduced susceptibility to the IGRs pyriproxyfen and methoprene. All populations tested were fully susceptible to pyrethroids. Biochemical assays revealed a significant up-regulation of GSTs in DDT-resistant populations in both larval and adult stages. Also, ß-esterases were up-regulated in the populations with incipient resistance to malathion. Of note, we identified a previously unknown amino acid polymorphism (Ph 'Leu) in domain III of the VGSC, in a location known to be associated with pyrethroid resistance in another container-inhabiting mosquito, Aedes aegypti L. The observed DDT resistance in populations from Florida may indicate multiple introductions of this species into the USA, possibly from tropical populations. In addition, the mechanisms underlying DDT resistance often result in pyrethroid resistance, which would undermine a remaining tool for the control of Ae. albopictus. Continued monitoring of the insecticide resistance status of this species is imperative.

Last Modified: 12/22/2014
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