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ABSTRACT--Species of true hugs were sampled, identified, and evaluated from nine diverse habitats on the 15,816 ha Arnold Air Force Base in Tennessee during a one-year study. Species were sampled [...]

ABSTRACT--The ant fauna in four eastern Tennessee mixed hardwood forest sites (cove, slope, open, and tornado-damaged) was sampled using pitfall traps during a two-year study. Ground-dwelling ants were collected at [...]

Hemlock woolly adelgid (HWA), Adelges tsugae (Annand), has caused widespread eastern hemlock mortality in the eastern U.S. HWA was first documented in Great Smoky Mountains National Park (GRSM) in 2002. Once documented, GRSM implemented an aggressive integrated pest management (IPM) program. As a part of this IPM strategy, systemic imidacloprid treatments have been widely used to preserve the Park’s hemlock resources. A retrospective study was conducted in cooperation with GRSM to examine the long-term effectiveness of imidacloprid treatments on different size hemlock trees. Of particular interest is olefin, a metabolite of imidacloprid, which is greater than 15 times more toxic to HWA than imidacloprid. The concentrations of imidacloprid and olefin were assessed in hemlock branchlets four to seven years post-imidacloprid treatment. Samples were collected from three strata of the canopy from each of four size classes (30, 45, 61, and 76 cm DBH). Imidacloprid and olefin were present in all size classes four to seven years after a single imidacloprid treatment. Hemlocks from the 61 and 76 cm size classes exhibited higher imidacloprid and olefin concentrations than the 45 cm hemlocks when larger hemlocks were given high-dose treatments. When all hemlocks were given low-dose treatments, 61 cm hemlocks had lower concentrations of olefin, but no significant differences in imidacloprid concentrations among size classes were detected. Olefin concentrations were higher in high-dose compared to low-dose treatments in 76 cm hemlocks. A significant linear relationship exists between the concentration of imidacloprid and olefin in individual branchlets. A model was developed to optimize the dose of imidacloprid based on the diameter of hemlock trees. Use of this model will result in smaller (<30 cm) and larger (>63 cm) hemlocks receiving lower doses of imidacloprid with expected HWA suppression numerous years after treatment. Information obtained from this study can assist resource managers in developing and modifying HWA suppression programs to maintain low HWA populations while reducing the amount of imidacloprid applied to individual hemlocks. Optimal pesticide applications based on specific hemlock diameters may result in more environmentally and economically sustainable hemlock management programs. [ABSTRACT FROM AUTHOR]

Imidacloprid, a neonicotinoid pesticide, is commonly used in hemlock woolly adelgid, Adelges tsugae (Annand) (HWA) (Hemiptera: Adelgidae), pest management programs to preserve hemlock resources. Great Smoky Mountains National Park (GRSM) has an extensive HWA integrated pest management program, with more than 200,000 individual hemlocks in the Park having received imidacloprid soil treatments. A retrospective study was conducted in cooperation with GRSM to assess imidacloprid and two of its insecticidal metabolites (5-hydroxy and olefin) are present in surface waters (i.e., streams) associated with HWA imidacloprid treatment areas. Thirty stream locations were sampled in GRSM to assess the presence and concentration of imidacloprid, 5-hydroxy, and olefin. Water samples were collected from 10 streams downstream from riparian areas where hemlocks received imidacloprid soil treatments and immediately upstream from hemlock treatment areas in each of the selected 10 streams. In addition, water samples were collected from 10 control streams each in close proximity to one of the 10 streams flowing through treatment areas. The concentrations of imidacloprid, 5-hydroxy, and olefin in parts per trillion (ppt) were determined by liquid chromatography mass spectroscopy (LC/MS). Data analysis included historical treatment data from GRSM. Data were analyzed using a Kruskal–Wallis test ( P < 0.05), least significant difference (LSD), and a multiple regression ( P < 0.05). Imidacloprid, in concentrations ranging from 28.5 to 379 ng L −1 , was detected in 7 of the 10 downstream sampling locations. Upstream or adjacent stream locations did not have detectable concentrations of imidacloprid. Five-hydroxy and olefin were not detected in any streams. A positive relationship between the total amount of imidacloprid applied to a hemlock treatment area and the concentration of detectable imidacloprid in the associated stream was observed. However, while imidacloprid was detected in streams associated with hemlock treatment areas, the concentrations are below USEPA chronic and acute aquatic life benchmarks for fish (1200 and 41,500 μg L −1 , respectively) and aquatic macroinvertebrates (1.05 and 34.5 μg L −1 , respectively). Since the amount of imidacloprid applied in a treatment area has an influence on the concentration of imidacloprid in streams, resource managers must carefully consider the frequency and extent of imidacloprid applications to meet management goals while providing minimal environmental impact. [ABSTRACT FROM AUTHOR]