PT - JOURNAL ARTICLE AU - Harrell, Mark TI - Imidacloprid Concentrations in Green Ash (<em>Fraxinus pennsylvanica</em>) Following Treatments with Two Trunk-Injection Methods AID - 10.48044/jauf.2006.017 DP - 2006 May 01 TA - Arboriculture &amp; Urban Forestry (AUF) PG - 126--129 VI - 32 IP - 3 4099 - http://auf.isa-arbor.com/content/32/3/126.short 4100 - http://auf.isa-arbor.com/content/32/3/126.full AB - Two imidacloprid trunk-injection products (PointerTM and Imicide®) were applied to green ash (Fraxinus pennsylvanica Marsh.) in May and July to compare the concentrations of imidacloprid in sap and leaf and trunk tissues after the injections. Sap samples were extracted from shoots 0, 3, 7, 30, 60, and 90 days after treatment and analyzed for imidacloprid. Dry leaf samples were analyzed for imidacloprid at 30 and 90 days after treatment. Combined xylem and cambial zone samples were analyzed for imidacloprid at 90 days after treatment at 0.5 m (1.65 ft) and 1.0 m (3.3 ft) above the injection sites. Sap imidacloprid concentrations in trees treated in May with Pointer were significantly higher than the untreated control at 7 days after treatment (P &lt; 0.05) but were not significantly different from the control on other days or different from Imicide on any day. Sap imidacloprid levels in trees treated in July with Pointer were significantly higher than the control at 30 days after treatment but were not significantly different from Imicide. Dry leaf imidacloprid levels in trees treated with Pointer were significantly higher than the Imicide and control treatments at 30 and 90 days after treatment. Xylem and cambial zone imidacloprid levels in trees treated with Pointer were significant higher than the Imicide and control treatments at 90 days after treatment at 1.0 m (3.3 ft) above the injection sites but were not significantly higher at 0.5 m (1.65 ft). No imidacloprid levels from Imicide were significantly different from those in the untreated control trees.