Journal of Medical Entomology (2014) 51, 170-181

Sin-Ying Koou, Chee-Seng Chong, Indra Vythilingam, Lee-Ching Ng and Chow-Yang Lee (2014)
Pyrethroid resistance in Aedes aegypti larvae (Diptera: Culicidae) from Singapore
Journal of Medical Entomology 51 (1), 170-181
Abstract: Wereport the first comprehensive insecticide susceptibility status of Aedes aegypti (L.) larvae from Singapore. The study indicated that Ae. aegypti is susceptible to temephos, although resistance (RR50 =1.29-4.43-fold) could be developing. Of high concern is the detection of moderate to high resistance to permethrin (RR50 = 29-47-fold) and etofenprox (RR50 = 14-34-fold). Biolarvicide Bacillus thuringiensis israelensis (Bti) remains effective. The insecticide susceptibility profile of Ae. aegypti larvae was found to be homogenous among the different sites studied across the island city. The addition of synergists piperonyl butoxide, S,S,S,-tributyl phosphorotrithioate, and triphenyl phosphate generally failed to enhance the toxicity of the insecticides investigated, suggesting an insignificant role of metabolic-based resistance, and a possible involvement of target site resistance. Further biochemical investigation of specific metabolic enzyme activities suggested that detoxifying enzymes, mono-oxygenases, esterases, glutathione S-transferases, and altered acetylcholinesterases, generally did not contribute to the resistance observed. This study clearly demonstrated that pyrethroid resistance is widespread among Ae. aegypti population and lowered susceptibility to organophosphates is developing.
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Database assignments for author(s): Chow-Yang Lee, Chee Seng Chong

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Aedes aegypti		Singapore
Bacillus thuringiensis var. israelensis (entomopathogen)	Aedes aegypti		Singapore