Journal of Medical Entomology (2019) 56, 1145-1149

Pia Untalan Olafson, Phillip E. Kaufman, Gérard Duvallet, José-Arturo Solórzano, David B. Taylor and Rebecca Trout Fryxell (2019)
Frequency of kdr and kdr-his alleles in stable fly (Diptera: Muscidae) populations from the United States, Costa Rica, France, and Thailand
Journal of Medical Entomology 56 (4), 1145-1149
Abstract: Anecdotal evidence of pyrethroid insecticide product failure for the control of stable fly [Stomoxys calcitrans (L.)] populations in the United States and worldwide prompted us to evaluate the frequency of knockdown resistance (kdr)-type polymorphisms within the voltage-sensitive sodium channel (Vssc) gene of field collected specimens from the United States, France, Costa Rica, and Thailand. The kdr-his allele (L1014H), associated with permethrin resistance, was detected in stable flies from the 10 states sampled in the United States, as well as from Costa Rica and France (Toulouse). Field collections of stable flies from California (Modesto) and New York (Cliffton Springs) exhibited reduced susceptibility upon exposure to a diagnostic permethrin concentration of 10× LC₉₉, but survival did not appear to strictly associate with frequency of the kdr-his allele. This suggests that there are additional resistance mechanisms contributing to the phenotype in these states. The kdr allele (L1014F) was detected for the first time in stable flies originating in France and Thailand, and an improved, DNA-based diagnostic assay was developed and validated for use in future screens for kdr and kdr-his allele frequencies from field collections. The absence of kdr in United States and Costa Rica populations suggests that the allele is currently restricted to Europe and Asia.
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Database assignments for author(s): Pia U. Olafson, Phillip E. Kaufman, David B. Taylor

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Stomoxys calcitrans		France
	Stomoxys calcitrans		Thailand
	Stomoxys calcitrans		Costa Rica
	Stomoxys calcitrans		U.S.A. (mid N)
	Stomoxys calcitrans		U.S.A. (mid S)
	Stomoxys calcitrans		U.S.A. (SE)