title: 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.
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.
authors.affiliation: Department of Entomology and Plant Pathology, 370 Plant Biotechnology Building, The University of Tennessee, Knoxville, TN 37996. ebenton3@utk.edu.
authors.forename: E P
authors.initials: EP
authors.lastname: Benton
authors.affiliation: Department of Entomology and Plant Pathology, 370 Plant Biotechnology Building, The University of Tennessee, Knoxville, TN 37996.
authors.forename: J F
authors.initials: JF
authors.lastname: Grant
authors.affiliation: Great Smoky Mountains National Park, 107 Park Headquarters Rd., Gatlinburg, TN 37738.
authors.forename: R J
authors.initials: RJ
authors.lastname: Webster
authors.affiliation: Great Smoky Mountains National Park, 107 Park Headquarters Rd., Gatlinburg, TN 37738.
authors.forename: R J
authors.initials: RJ
authors.lastname: Nichols
authors.affiliation: The Connecticut Agricultural Experiment Station, 153 Cook Hill Rd., Windsor, CT 06095.
authors.forename: R S
authors.initials: RS
authors.lastname: Cowles
authors.affiliation: Department of Chemistry, 800 Lancaster Ave., Villanova University, Villanova, PA 19085-1699.
authors.forename: A F
authors.initials: AF
authors.lastname: Lagalante
authors.affiliation: Department of Entomology and Plant Pathology, 370 Plant Biotechnology Building, The University of Tennessee, Knoxville, TN 37996.
authors.forename: C I
authors.initials: CI
authors.lastname: Coots
mesh_terms: D000475:Alkenes / Q000032:analysis; D000818:Animals; D006430:Hemiptera; D007093:Imidazoles / Q000378:metabolism*; D007306:Insecticides / Q000378:metabolism*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000378:metabolism*; D010573:Pesticide Residues / Q000032:analysis*; D028225:Tsuga / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000475:Alkenes; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010573:Pesticide Residues; C082359:imidacloprid
keywords: Adelges tsugae; eastern hemlock; hemlock woolly adelgid; imidacloprid; olefin