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.

Improving the design elements of sprayers to improve technologies in the protection of black currant against pests

“…The application of insecticides to protect plantings against the dominant groups of sucking pests and obtaining stable harvests depend primarily on the timely qualitative and effective treatment [4]. Chemical means for combating the harmful organisms require highly efficient equipment [5].…”

“…Technical efficiency of preparations was assessed by the accounts of pest population and was computed by the Henderson-Tilton formula (4).…”

Stream Salamander and Benthic Macroinvertebrate Community Responses to Imidacloprid Exposure

“…Imidacloprid is commonly used in agriculture been implemented to manage the spread and impacts of nonnative forest insects (e.g., , Lamb et al 2006, Muzika 2017. One of the most common approaches is application of systemic insecticides through soil drenches, injections, or tablets (Kovacs et al 2010, Meng et al 2015, with imidacloprid being the most widely used insecticide for management of hemlock woolly adelgid infestations (Dilling et al 2010, Turcotte et al 2017. Soil treatments are substantially more effective than trunk injections, and are thus recommended (Cowles et al 2006, Cowles andLagalante 2009).…”

“…Few studies have investigated non-target impacts of imidacloprid on amphibians, and most previous research focused on assessing lethal concentrations and genotoxicity to anuran tadpoles (e.g., . The Appalachian region is a global biodiversity hotspot for salamanders (Buckley andJetz 2007, Rissler andSmith 2010), and imidacloprid is widely used to preserve hemlock stands in the region (Turcotte et al 2017). Imidacloprid applied to soil in forest systems can leach into surrounding aquatic habitats , and thus assessing potential impacts on aquatic and aquatic-stage amphibians is relevant in these systems.…”

Imidacloprid Bark Treatment for Hemlock Woolly Adelgid (Adelges tsugae)

“…Of the samples tested, significant differences were found; 27% had detectable levels of imidacloprid in both xylem fluid and needle tissue, 14% had levels on in the xylem fluid and not in the leaf tissue, 23% were vice versa, and 36% had no detectable levels in either. This implies insecticide movement is intermittent (Turcotte et al 2017).…”