Journal of Economic Entomology (2014) 107, 773-780

Nilima Prabhaker, Steven Castle and Thomas M. Perring (2014)
Baseline susceptibility of Bemisia tabaci B biotype (Hemiptera: Aleyrodidae) populations from California and Arizona to spirotetramat
Journal of Economic Entomology 107 (2), 773-780
Abstract: Baseline toxicity levels to foliarly applied spirotetramat were established for 19 field populations of whiteflies, Bemisia tabaci (Gennadius) B biotype (= Bemisia argentifolii Bellows and Perring) (Hemiptera: Aleyrodidae) from Arizona and California in 2008 and 2009. The susceptibility data were determined against the second instar of B. tabaci field collections before the registration and widespread use of spirotetramat in California. Three strains of whitefly, resistant to either bifenthrin, imidacloprid, or pyriproxyfen, were also tested to determine the potential for cross-resistance to spirotetramat. No significant geographic variation in susceptibility to spirotetramat was observed among regions within Arizona. The LC₅₀ values for the Arizona populations spanned a 14-fold range between populations during the 2 yr sampling tests including a low LC₅₀ of 0.91 (µg [AI] ml^-1) and a high LC₅₀ of 13.47 (µ [AI] ml^-1), while the LC₉₀ values showed a seven-fold range. The field populations from California exhibited limited variation in susceptibility to spirotetramat in general (1.02-7.02 µg [AI] ml^-1) with one exception (27.98 µg [AI] ml^-1). Variation in susceptibility among the resistant strains was about eight-fold at the LC₅₀ level with the PYR-strain, showing the highest susceptibility to spirotetramat at 3.79 (µg [AI] ml^-1). In addition, comparisons of relative susceptibilities among three older immature instars of two field populations showed no significant differences. These results establish a regional baseline that can serve as a reference for future monitoring and management of B. tabaci resistance to spirotetramat.
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Database assignments for author(s): Nilima Prabhaker, Thomas M. Perring, Steven J. Castle

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.
	Bemisia tabaci biotype MEAM1	Beans (Phaseolus)	U.S.A. (SW)
	Bemisia tabaci biotype MEAM1	Cotton (Gossypium)	U.S.A. (SW)
	Bemisia tabaci biotype MEAM1	Cucumber (Cucumis sativus)	U.S.A. (SW)
	Bemisia tabaci biotype MEAM1	Melon (Cucumis melo)	U.S.A. (SW)