Journal of Economic Entomology (2015) 108, 2672-2682

E.P. Benton, J.F. Grant, R.J. Webster, R.J. Nichols, R.S. Cowles, A.F. Lagalante and C.I. Coots (2015)
Assessment of imidacloprid and its metabolites in foliage of eastern hemlock multiple years following treatment for hemlock woolly adelgid, Adelges tsugae (Hemiptera: Adelgidae), in forested conditions
Journal of Economic Entomology 108 (6), 2672-2682
Abstract: Widespread decline and mortality of eastern hemlock, Tsuga canadensis (L.) Carrière, have been caused by hemlock woolly adelgid, Adelges tsugae (Annand) (HWA) (Hemiptera: Adelgidae). The current study is a retrospective analysis conducted in collaboration with Great Smoky Mountains National Park (GRSM) to determine longevity of imidacloprid and its insecticidal metabolites (imidacloprid olefin, 5-hydroxy, and dihydroxy) in GRSM's HWA integrated pest management (IPM) program. Foliage samples were collected from three canopy strata of hemlocks that were given imidacloprid basal drench treatments 4–7 yr prior to sampling. Foliage was analyzed to assess concentrations in parts per billion (ppb) of imidacloprid and its metabolites. Imidacloprid and its olefin metabolite were present in most, 95 and 65%, respectively, branchlets 4–7 yr post-treatment, but the 5-hydroxy and dihydroxy metabolites were present in only 1.3 and 11.7%, respectively, of the branchlets. Imidacloprid and olefin concentrations significantly decreased between 4 and 7 yr post-treatment. Concentrations of both imidacloprid and olefin were below the LC₅₀ for HWA 5–7 yr post-treatment. Knowledge of the longevity of imidacloprid treatments and its metabolite olefin can help maximize the use of imidacloprid in HWA IPM programs.
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Link to article at publishers website
Database assignments for author(s): Richard S. Cowles

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Adelges tsugae	Hemlock (Tsuga)	U.S.A. (SE)