Table of Contents Edward F. Gilman, Maria Paz, and Chris Harchick Retention Time in Three Nursery Container Volumes Impacts Root Architecture ........................ 146 Abstract. Four general-use insecticides (Astro®, Onyx®, Dominion® Tree & Shrub, and Xytect 2F®) were evaluated for their effective- ness at preventing attacks by the southern pine beetle (SPB) (Dendroctonus frontalis) and the small southern pine engraver (Ips avulsus) using a previously developed small-bolt method. Evaluations were conducted between 58 and 126 days post treatment. South- ern pine beetles from New Jersey and Mississippi, U.S., were evaluated using a mixture of field and laboratory small-bolt trials; beetle origin did not appear to affect results. Astro and Onyx bole sprays were effective at reducing or eliminating attack by SPB, while the imidacloprid soil drench products (Dominion and Xytect) were ineffective. With I. avulsus in Louisiana, U.S., Astro was effective at reducing bole utilization at 58 and 83 days posttreatment but failed at 126 days. Onyx, Dominion, and Xytect were ineffec- tive against I. avulsus in these tests. Imidacloprid phloem residues averaged 0.74 (µg/g phloem dry weight) for Dominion and 1.31 for Xytect, values that are similar to other studies but low for purposes of control. These results support previous findings that sys- temic imidacloprid is ineffective for protecting pines against Dendroctonus bark beetles and that bole sprays with bifenthrin or per- methrin can be effective. However, permethrin was the only active ingredient that was effective against I. avulsus in the current study. Key Words. Bifenthrin; Dendroctonus frontalis; Imidacloprid; Insecticide; Ips avulsus; Mississippi; New Jersey; Permethrin; Pinus; Soil Drench; Southern Pine Beetle; Southern Pine Engraver; Systemic Insecticide. Edward F. Gilman, Maria Paz, and Chris Harchick Container Wall Porosity and Root Pruning Influence on Swietenia mahogani Root Ball Architecture and Anchorage After Planting .................................................................. 155 Abstract. The emerald ash borer (EAB), first discovered in North America in Michigan in 2002, continues to expand its distributional range. Early detection of EAB remains a major caveat in efforts to implement proactive management strategies. Past reports have shown that ash trees infested with EAB have an increased risk of branch failure and other symptoms associated with tree decline. Therefore, early detection efforts could be improved if a suite of tree symptoms—prior to visible signs of EAB infestation—can be identified. Researchers initiated a four-year study in Ohio, U.S. (2009– 2012) to investigate and document symptoms associated with the EAB–ash tree complex in urban sites. The prior history of EAB at the study sites ranged from ash trees with no visible evidence of infestation to those that were infested for more than two years. In trees shown to be recently colonized by EAB, visible signs of infestation, such as adult emergence holes, presence of EAB galleries, bark loss, and canopy loss were not always apparent. However, in EAB-positive trees, there was a significant tendency for the presence of cracks in scaffold branches, branch fractures within the upper canopy, and branch fractures specifically located closer to the union with the stem as opposed to at the branch tip or at the branch’s center of gravity. This study highlights tree symptoms associated with the initial colonization of EAB when host trees are still apparently healthy, which could greatly facilitate future detection efforts for EAB. Key Words. Agrilus planipennis; Arboriculture; Ash; Branch Fracture; Early Detection; Emerald Ash Borer; Fraxinus; Invasive Species; Scaffold Crack; Urban Forestry. ©2015 | International Society of Arboriculture | ISSN:1935-5297
May 2015
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