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Eastern hemlock (Tsuga canadensis [L.] Carrière) is an important component of the riparian ecosystem. Due to the widespread establishment of hemlock woolly adelgid (Adelges tsugae Annand)(HWA) across the range of eastern hemlock, woodland trees may be infested for extended periods (years), resulting in their decline. Imidacloprid, a systemic neonicotinoid insecticide, may be used as a strategy in forested settings to manage HWA while more long-term solutions become established, such as biological controls. Symptoms of prolonged infestation include extensive dieback and thinned canopies. In this study, trees with a diameter at breast height (DBH) of 24.7 ± 2.7 SD cm in poor condition were treated with imidacloprid. Trees were treated once by trunk-injection (IMA-jet) or by soil drench in the Greenbrier area of the Great Smoky Mountains National Park, Gatlinburg, TN, USA. Changes in tree growth and HWA density were measured for 3 consecutive years. Imidaclopridtreated trees recovered, whereas the untreated trees declined. Imidacloprid treatments resulted in significantly higher 3-year mean percent growth (65.6% to 71.7% of tips) compared to the untreated controls (10.5% of tips). HWA density 3-year means in the imidacloprid-treated trees (0.10 to 1.09 per cm) likewise were statistically different to the untreated trees (2.72 per cm). The extended activity of imidacloprid-treated hemlock was attributed to storage in the symplast (xylem ray parenchyma) and to perennial needle retention. This study demonstrates that trunk-injection with IMA-jet is effective against HWA and comparable with soil drench to protect trees in the long term (≥ 4 years). [ABSTRACT FROM AUTHOR]

The protection of high-value trees against bark beetles and the development of alternatives to bole sprays is a priority for the tree manager. The objective of this study was to evaluate stem-injected TREE-äge® (emamectin benzoate [EB]) as a protective treatment for western white pines (Pinus monticola Dougl. ex D. Don) against mountain pine beetle (MPB, Dendroctonus ponderosae Hopkins). Treatment efficacy was based solely on tree mortality as per Shea protocols (i.e., ≥ 60% check vs. ≤ 20% treated tree mortality). Our first experiment was installed in 2007 and included trees stem-injected with TREE-äge and untreated controls. Bole application of S-(-)-verbenone and green leaf volatile (GLV) blend was included for observational comparison. Pressure from MPB was heavy, as indicated by the number and timing of control tree mortality (90%). Strip attacks by MPB in TREE-äge trees indicated that the impacts of EB, and by inference its distribution, were inconsistent. In 2009, the injection protocol was revised to improve EB distribution in the phloem via closer injection points. In the 2009 TREE-äge-treated trees, adult beetle mining stopped when they contacted phloem and was insufficient to cause tree death by girdling. Blue-stain fungi colonized the sapwood of trees in both studies. Isolates from autopsied trees treated with TREE-äge alone were subsequently identified as Grosmannia clavigera and Leptographium longiclavatum (Ophiostomatales: Ascomycota), species that can incite tree mortality. In 2013, we revised our protocol to include GLV plus verbenone or propiconazole with TREE-äge, wherein these treatments proved effective in protecting trees against MPB and their associated pathogenic fungi. [ABSTRACT FROM AUTHOR]

Diplodia tip blight (Diplodia pinea) affects mature pines, including Austrian (Pinus nigra) and Ponderosa (P. ponderosa) pines. Infections spread from needle fascicles to branch and, if unchecked, to the entire tree. Efficacy studies of fungicide injections in conifers are limited. Minute vascular tissues and resin exudate, a response to drilling, present impediments to injection. The efficacy of Propizol (14.3% propiconazole) for control of Diplodia tip blight in Austrian pines was evaluated. We evaluated (1) time of year, (2) injection spacing, and (3) fungicide dilution with respect to injection efficiency. Late fall injections expedited uptake, which is consistent with the reduced monoterpene emission rates in autumn and winter reported by Kim et al. 2005 and Lim et al. 2008. The time required for the dose to be administered was recorded for close and wide spacing of injection sites. Close spacing had the greatest impact on reducing the application time, irrespective of time of year. Low volume injections required less time to apply compared to high volume. Regardless of the application method, we observed a significant decrease in disease incidence in Propizol-treated trees. Injections applied in late fall resulted in a mean reduction in infections of new candles in the next growing season. Injections in the following spring, however, did not result in improvement in candle condition until a year later. We believe that these differences are based on whether the fungicide was applied prior to or after infection. Based on these findings, we recommend Propizol prior to infection for optimal results. [ABSTRACT FROM AUTHOR]

BACKGROUND The invasive goldspotted oak borer, Agrilus auroguttatus, is threatening the health and survival of oak trees in San Diego County, California. From two sites in the core area of the infestation, we report a 2.5 year investigation of the impact of A. auroguttatus on coast live oak, Quercus agrifolia, before and after treatment with two systemic insecticides, emamectin benzoate ( EB) and imidacloprid ( IC). RESULTS None of the 446 survey trees died during the study. The crown dieback rating of most trees at both study sites remained unchanged, regardless of insecticide treatment. A higher cumulative increase in the number of A. auroguttatus emergence holes was observed on trees that were previously infested and on trees with larger diameters. Over the 2.5 year period, the new infestation rates of initially uninfested trees across the untreated and treated groups were 50% ( EB) and 32% ( IC), and neither EB nor IC treatment affected cumulative increases in the number of emergence holes. EB-injected trees did not have significant annual increases in the number of A. auroguttatus emergence holes at either 1.5 or 2.5 years compared with that at 0.5 years, whereas untreated trees had significant annual increases. Although IC-injected trees had a significantly greater annual increment in the number of emergence holes than untreated trees during the last year of the study, treated trees had significant reductions in annual increases in emergence holes at both 1.5 and 2.5 years compared with that at 0.5 years. Untreated trees had no significant reduction in the annual increase in emergence holes at 1.5 and 2.5 years. CONCLUSIONS A. auroguttatus preferentially attacked previously infested and larger (diameter at breast height > 15-30 cm) oak trees, but the attacks led to very gradual changes in the health of the trees. Both EB and IC provided minor suppressive effects on A. auroguttatus emergence. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

The article discusses a study on the use of imidacloprid insecticide as a treatment strategy for hemlock woolly adelgid (HWA) infested eastern hemlock trees. The authors examined HWA-infested trees by collecting data on changes in tree growth, HWA density, and imidacloprid residues for three years. The study found that trees treated with imidacloprid recovered and accumulated compound in the canopy.

The article presents a study on the effectiveness of systemic fungicides for reducing the size of lesions in loblolly pine after inoculation with Ophiostoma minus or bluestain fungus. The researchers injected every selected tree around its base with the systemic fungicide using the Tree I.V. system and Arborplugs. They also applied three systemic fungicide products to loblolly pines by stem-injection in order to assess activity against O. minus.

The article discusses a research study on how healthy and compromised green ash trees respond to wounds caused by standard trunk injection treatments. Two green ash trees were randomly selected from each of seven trunk-injection treatments that were chosen to represent a range of efficacy based on the active ingredient and the insecticide was injected in relationship to the borer infestation. It suggests that tree injections are tolerated in healthy green ash and have the potential as a tool to protect trees against exotic and destructive pests.

The article discusses research on green ash street trees whose trunks were injected with emamectin benzoate for emerald ash borer protection in Michigan in 2005 or 2006. The health of the trees was observed by yearly canopy thinning and dieback ratings for up to four years following a single treatment. For 2-3 years, a single trunk injection treatment of emamectin benzoate offered complete control of emerald ash borer larvae in 98 of 99 treated trees. Canopy ratings for treated trees remained the same for 2-4 years after trunk injection.

The article presents a study on the effectiveness of the insecticides imidacloprid and emanmectin benzoate in treating erythrina gall wasp (EGW) in coral trees. The study was administered by selecting 60 EGW infected trees treated with the two insecticides wherein its pre and post treatment injury as well as canopy foliage density was assessed using spherical densiometer. The study reveals that the insecticides affects canopy recovery and imidacloprid is the only effective treatment for EGW.

The article investigates the efficacy and duration of trunk-injected imidocloprid insecticide in the management of Hemlock woolly adelgid (HWA). Treatment with stem-injected imidacloprid did not provide a fast knockdown of the HWA. Rather, it required time, at least one year. In the year after a second treatment, high HWA mortality for hemlock to resume growth was observed.

Hemlock woolly adelgid (Adelges tsugae Annand) is an introduced homopteran that infests native eastern hemlock (Tsuga canadensis Cartiere). It results in reduced tree vitality and, when untreated, death. A state-of-the-art microinjection device employing an air-over-hydraulic system was used to deliver a therapeutic dosage of imidacloprid into the active xylem tissues of affected hemlocks. Bioassays were conducted microscopically to determine HWA mortality post-treatment. Injected trees had significantly (p < 0.05) lower HWA populations compared to untreated controls; mean mortality for injected trees was over twice that of noninjected trees. The Arborjet VIPER system shows promise as a management tool in the treatment of HWA. [ABSTRACT FROM AUTHOR]

The article discusses a study which compared the effectiveness of manganese sulfate (MnSO4) in increasing foliar Mn concentrations when applied to the soil or injected into the trunk or petioles of palms. The study used a 29-year-old Fiji Dwarf coconut palms with trunk heights of 3-4.5 meters. The study found that trunk injections cause permanent wounds that could serve as entry points for the trunk pathogen Thielaviopsis paradoxa.