title: Spatial and temporal distribution of trunk-injected (14) C-imidacloprid in Fraxinus trees.
abstract: BACKGROUND
  Since the discovery of Agrilus planipennis Fairmaire (emerald ash borer) in 2002, researchers have tested several methods of chemical control. Soil drench or trunk injection products containing imidacloprid are commonly used to control adults. However, efficacy can be highly variable and may be due to uneven translocation of systemic insecticides. The purpose of this study was to determine whether sectored xylem anatomy might influence imidacloprid distribution in tree crowns.
  
  
  RESULTS
  Imidacloprid equivalent concentrations were higher in leaves from branches in the plane of the injection point (0°) than in leaves from branches on the opposite side of the injection point (180°). Leaves from branches 90° to the right of injection points had higher imidacloprid equivalent concentrations than leaves from branches 90° to the left of injection points. Leaves and shoots had higher imidacloprid equivalent concentrations than roots and trunk cores, indicating that imidacloprid moves primarily through the xylem.
  
  
  CONCLUSIONS
  Imidacloprid equivalent concentration in leaves varied over time and in relation to injection points. It is concluded that ash trees have sectored 'zigzag' xylem architecture patterns consistent with sectored flow distribution. This could lead to variable distribution of imidacloprid in tree crowns and therefore to variable control of A. planipennis.
authors.affiliation: Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA. tanissar@msu.edu
authors.forename: Sara R
authors.initials: SR
authors.lastname: Tanis
authors.forename: Bert M
authors.initials: BM
authors.lastname: Cregg
authors.forename: David
authors.initials: D
authors.lastname: Mota-Sanchez
authors.forename: Deborah G
authors.initials: DG
authors.lastname: McCullough
authors.forename: Therese M
authors.initials: TM
authors.lastname: Poland
mesh_terms: D000818:Animals; D001517:Coleoptera / Q000187:drug effects* / Q000502:physiology; D031661:Fraxinus / Q000378:metabolism* / Q000469:parasitology; D007093:Imidazoles / Q000378:metabolism* / Q000494:pharmacology; D007300:Insect Control; D007306:Insecticides / Q000378:metabolism* / Q000494:pharmacology; D000073943:Neonicotinoids; D009574:Nitro Compounds / Q000378:metabolism* / Q000494:pharmacology; D018547:Plant Stems / Q000378:metabolism*; D014197:Trees / Q000378:metabolism* / Q000469:parasitology
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; C082359:imidacloprid