title: Spatial and Temporal Distribution of Imidacloprid Within the Crown of Eastern Hemlock.
abstract: Systemic imidacloprid is the most widely used insecticide to control the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), an exotic pest of eastern hemlock, Tsuga canadensis (L.) Carriére in the United States. This study was conducted to 1) determine the effect of treatment timing (spring vs. fall) and application method (trunk injection vs. soil injection) on the spatial and temporal distribution of imidacloprid within the crown of A. tsugae-free eastern hemlock using a competitive enzyme-linked immunosorbent assay (ELISA), 2) compare ELISA to gas chromatography-mass spectrometry (GC/MS) for the detection of imidacloprid in xylem fluid, and 3) determine the concentration of imidacloprid in leaf tissue using high performance liquid chromatography with tandem mass spectrometric (LC/MS/MS) detection methods. Xylem fluid concentrations of imidacloprid were found to be significantly higher for spring applications than for fall applications and for trunk injections than soil injections in the first year posttreatment. A total of 69% of samples analyzed by ELISA gave 1.8 times higher concentrations of imidacloprid than those found by GC/MS, leading to evidence of a matrix effect and overestimation of imidacloprid in xylem fluid by ELISA. A comparison of the presence of imidacloprid with xylem fluid and in leaf tissue on the same branch showed significant differences, suggesting that imidacloprid moved intermittently within the crown of eastern hemlock.
authors.affiliation: USDA Forest Service, Forest Health Protection, 180 Canfield Street, Morgantown, WV 26505.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Turcotte
authors.affiliation: Department of Chemistry, Villanova University, Villanova, PA 19085.
authors.forename: Anthony
authors.initials: A
authors.lastname: Lagalante
authors.affiliation: Department of Chemistry, Villanova University, Villanova, PA 19085.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Jones
authors.affiliation: Department of Chemistry, Villanova University, Villanova, PA 19085.
authors.forename: Frank
authors.initials: F
authors.lastname: Cook
authors.affiliation: Plant Protection and Quarantine USDA Animal Plant Health Inspection Service, Morgantown, WV 26505.
authors.forename: Thomas
authors.initials: T
authors.lastname: Elliott
authors.affiliation: Department of Statistics, West Virginia University, Morgantown, WV 26506.
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Billings
authors.affiliation: Division of Plant and Soil Science, West Virginia University, Morgantown, WV 26506 yopark@mail.wvu.edu.
authors.forename: Yong-Lak
authors.initials: YL
authors.lastname: Park
mesh_terms: D000818:Animals; D004797:Enzyme-Linked Immunosorbent Assay; D020387:Food Chain; D008401:Gas Chromatography-Mass Spectrometry; D006430:Hemiptera / Q000502:physiology; D007093:Imidazoles / Q000378:metabolism*; D007300:Insect Control; D007306:Insecticides / Q000378:metabolism*; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry; D012621:Seasons; D028225:Tsuga / Q000378:metabolism*; D052584:Xylem / Q000737:chemistry
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid
keywords: ELISA; Imidacloprid; hemlock woolly adelgid; insecticide distribution