Journal of Economic Entomology (2013) 106, 393-399

Siddharth Tiwari, Nabil Killiny and Lukasz L. Stelinski (2013)
Dynamic insecticide susceptibility changes in Florida populations of Diaphorina citri (Hemiptera: Psyllidae)
Journal of Economic Entomology 106 (1), 393-399
Abstract: Five field populations of Diaphorina citri Kuwayama from various regions of Florida were evaluated in 2011 for resistance to commonly used insecticides. Three diagnostic doses (LD₅₀, LD₇₅, and LD₉₅), developed in 2009 using a laboratory susceptible population, were used to measure changes in susceptibility levels of field-collected populations as compared with a susceptible laboratory population. Further reductions in the susceptibility levels of D. citri to chlorpyriphos and fenpropathrin were determined, compared with results obtained in 2010. Mean percent mortality obtained from all five locations was significantly lower than observed with the laboratory susceptible population for all insecticides tested. Previously, expression of five CYP4 genes was implicated in contributing to insecticide metabolism in D. citri. In the current study, we compared the relative expression of these five CYP4 genes and their associated levels of protein expression among field-collected and laboratory susceptible populations. Expression of all CYP4 genes investigated was higher in field-collected populations when normalized against the laboratory susceptible population. There was an increased signal of a band corresponding to a 45 kDa protein in four of the five field populations as measured by the Western blot assay, which suggests increased production of cytochrome P450 enzymes. The current results indicate that insecticide resistance continues to increase in Florida populations of D. citri, particularly to chlorpyriphos and fenpropathrin. However, there was no further decrease in susceptibility of Florida populations of D. citri to neonicotinoid insecticides in 2011 as compared with previous years.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Kirsten S. Pelz-Stelinski, Nabil Killiny, Lukasz Stelinski

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.
	Diaphorina citri		U.S.A. (SE)