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Background: There is controversial evidence regarding the impact of clinically relevant postoperative intra-abdominal collections (CR-IC) on the clinical course after pancreaticoduodenectomy. C-reactive Protein (CRP) has been validated as a predictor of postoperative pancreatic fistula (POPF). Still, its role in predicting CR-IC has not been studied. Methods: A retrospective analysis was conducted on patients who underwent PD at a tertiary hospital between October 2012 and October 2017. The incidence of CR-IC, clinically relevant POPF and other complications, as well as mortality and length of hospitalisation, was retrieved. The impact of CR-IR on mortality and major complications was analysed. The serum CRP levels were retrieved on the third and fifth postoperative days (POD3 and POD5), followed by an analysis of sensitivity, specificity, and area under the curve to predict CR-IC using CRP. Results: One hundred forty patients were enrolled following inclusion and exclusion criteria. The mean age was 66.5 years (15–83). The incidence of CR-IC was 33.7% (47), and CR-POPF was 24.3%. Pancreatic duct diameter ≤ 4 mm was identified as a risk factor related to CR-IC occurrence. The group of patients who developed CR-IC after PD exhibited a higher rate of complications Clavien-Dindo ≥ III compared to patients without CR-IC (40.4% vs 7.5%, p < 0.001), as well as other events such as admission to the intensive care unit (25.5% vs 4.3%, p < 0.001), the incidence of CR-POPF (66% vs 3.2%, p < 0.001), prolonged hospital stay (32 vs 13 days, p < 0.001), postoperative haemorrhage (23.4 vs 5.4%, p = 0.002), and delayed gastric empty (38.8% vs 11.8%, p < 0.001) respectively. Logistic regression analysis identified CR-IC related to POPF as a risk factor for Clavien-Dindo > III: OR = 10.6 (95% CI: 3.90–28.7). No differences in mortality were reported between the CR-IC group and non-CR-IC group. CRP at postoperative day 3 (POD3) > 17.55 mg/dl and CRP at postoperative day 5 (POD5) > 13.46 mg/dl were predictors of CR-IC (AUC: 0.731 and AUC:0.821, respectively). Conclusions: CR-IC has a significant impact after pancreaticoduodenectomy and is associated with a higher incidence of Clavien-Dindo ≥ III complications. Additionally, CRP levels at POD3 and POD5 play a role in predicting CR-IC. Prospective studies are essential to explore strategies for mitigating the occurrence of CR-IC after PD. [ABSTRACT FROM AUTHOR]

5Effects of 8-week cold pre-germination treatment and gibberellic acid on (a) germination and (b) conversion of synchronized embryos of two culture lines derived from seeds of two different source trees (LA111-2 and LA-112-10). (a) Effect of seed collection date and source tree on embryogenesis induction from zygotic embryos from lingering white ash source trees (LA-101, LA-102, LA-114 and LA-116) in 2013 experiment. [Extracted from the article]

Emerald ash borer (Agrilus planipennis; EAB) has devastated populations of ash (Fraxinus spp.) trees in dozens of U.S. states and Canada over the past few decades. The continued survival of scattered ash trees known as "lingering ash" in heavily infested natural stands, however, offers evidence of genetic resistance or tolerance to EAB. These surviving or "lingering" ash individuals may form the basis for reforestation programs in EAB-impacted areas, and clonal mass-propagation of these genotypes can help accelerate these efforts. Between 2013 and 2018, we initiated embryogenic cultures by culturing immature zygotic embryos from open-pollinated (OP) seeds collected from several surviving white ash and green ash trees in Michigan and Pennsylvania. In addition, in 2018, we initiated cultures from crosses made between lingering green ash parents from the USDA Forest Service ash breeding program in Ohio. Somatic embryos were produced by growing cultures in liquid suspension, followed by fractionation and plating on semisolid medium to produce developmentally synchronous populations of somatic embryos. Somatic embryo germination and conversion were enhanced by a combination of pre-germination cold treatment and inclusion of activated charcoal and gibberellic acid in the germination medium. Ash somatic seedlings derived from OP explants grew rapidly following transfer to potting mix and somatic seedlings representing nine ash clones were acclimatized, grown in the greenhouse and planted in a preliminary field test, along with EAB-resistant Manchurian ash (F. mandshurica) and EAB-susceptible control seedlings. Somatic seedlings have now been produced from cultures that originated from seeds derived from the progeny of lingering green ash parents and an ex vitro germination protocol has shown some promise for accelerating early somatic seedling growth. Results of this research could provide the basis for scaled-up production of EAB-resistant ash varieties for seed orchard production for forest restoration and cultivar development for urban tree restoration. [ABSTRACT FROM AUTHOR]

Background: The impact of pre-existing comorbidities on acute pancreatitis (AP) mortality is not clearly defined. Our study aims to determine the trend in AP hospital mortality and the role of comorbidities as a predictor of hospital mortality. Methods: We analyzed patients aged ≥ 18 years hospitalized with AP diagnosis between 2016 and 2019. The data have been extracted from the Spanish National Hospital Discharge Database of the Spanish Ministry of Health. We performed a univariate and multivariable analysis of the association of age, sex, and comorbidities with hospital mortality in patients with AP. The role of the Charlson and Elixhauser comorbidity indices as predictors of mortality was evaluated. Results: A total of 110,021 patients diagnosed with AP were hospitalized during the analyzed period. Hospital mortality was 3.8%, with a progressive decrease observed in the years evaluated. In multivariable analysis, age ≥ 65 years (OR: 4.11, p < 0.001), heart disease (OR: 1.73, p < 0.001), renal disease (OR: 1.99, p < 0.001), moderate-severe liver disease (OR: 2.86, p < 0.001), peripheral vascular disease (OR: 1.43, p < 0.001), and cerebrovascular disease (OR: 1.63, p < 0.001) were independent risk factors for mortality. The Charlson > 1.5 (OR: 2.03, p < 0.001) and Elixhauser > 1.5 (OR: 2.71, p < 0.001) comorbidity indices were also independently associated with mortality, and ROC curve analysis showed that they are useful for predicting hospital mortality. Conclusions: Advanced age, heart disease, renal disease, moderate-severe liver disease, peripheral vascular disease, and cerebrovascular disease before admission were independently associated with hospital mortality. The Charlson and Elixhauser comorbidity indices are useful for predicting hospital mortality in AP patients. [ABSTRACT FROM AUTHOR]

Some introduced species cause severe damage, although the majority have little impact. Robust predictions of which species are most likely to cause substantial impacts could focus efforts to mitigate those impacts or prevent certain invasions entirely. Introduced herbivorous insects can reduce crop yield, fundamentally alter natural and managed forest ecosystems, and are unique among invasive species in that they require certain host plants to succeed. Recent studies have demonstrated that understanding the evolutionary history of introduced herbivores and their host plants can provide robust predictions of impact. Specifically, divergence times between hosts in the native and introduced ranges of a nonnative insect can be used to predict the potential impact of the insect should it establish in a novel ecosystem. However, divergence time estimates vary among published phylogenetic datasets, making it crucial to understand if and how the choice of phylogeny affects prediction of impact. Here, we tested the robustness of impact prediction to variation in host phylogeny by using insects that feed on conifers and predicting the likelihood of high impact using four different published phylogenies. Our analyses ranked 62 insects that are not established in North America and 47 North American conifer species according to overall risk and vulnerability, respectively. We found that results were robust to the choice of phylogeny. Although published vascular plant phylogenies continue to be refined, our analysis indicates that those differences are not substantial enough to alter the predictions of invader impact. Our results can assist in focusing biosecurity programs for conifer pests and can be more generally applied to nonnative insects and their potential hosts by prioritizing surveillance for those insects most likely to be damaging invaders. [ABSTRACT FROM AUTHOR]

Widespread mortality of native North American ash caused by emerald ash borer (EAB; Agrilus planipennis Fairmaire) threatens native arthropod biodiversity, but hybrid ash populations with resistance to EAB may serve a role in supporting threatened communities of arthropods in managed landscapes impacted by EAB.In this study, we investigated the hypothesis that a North American × Asian hybrid ash could serve as a refuge for North American arthropods in a common garden experiment by comparing beetle communities and herbivory on North American green and black ash, the Asian Manchurian ash, and the black × Manchurian hybrid 'Northern Treasure' ash.We found that ash specialists were rare among trees in the common garden. Species richness and composition of herbivorous beetles, as well as levels of herbivory, were similar among ash taxa, and these patterns were driven by native generalists.The lack of ash specialists collected suggests that regions that have experienced late stages of EAB‐induced ash mortality may have missed the opportunity to conserve populations of native specialist herbivores with EAB‐resistant ash genotypes. To maximize the potential for conserving native arthropod biodiversity of ash, it may be necessary to plant resistant ash prior to widespread EAB‐induced ash mortality, prioritizing efforts on the leading edge of expanding distribution of EAB. [ABSTRACT FROM AUTHOR]

Non-native organisms have invaded novel ecosystems for centuries, yet we have only a limited understanding of why their impacts vary widely from minor to severe. Predicting the impact of non-established or newly detected species could help focus biosecurity measures on species with the highest potential to cause widespread damage. However, predictive models require an understanding of potential drivers of impact and the appropriate level at which these drivers should be evaluated. Here, we used non-native, specialist herbivorous insects of forest ecosystems to test which factors drive impact and if there were differences based on whether they used woody angiosperms or conifers as hosts. We identified convergent and divergent patterns between the two host types indicating fundamental similarities and differences in their interactions with non-native insects. Evolutionary divergence time between native and novel hosts was a significant driver of insect impact for both host types but was modulated by different factors in the two systems. Beetles in the subfamily Scolytinae posed the highest risk to woody angiosperms, and different host traits influenced impact of specialists on conifers and woody angiosperms. Tree wood density was a significant predictor of host impact for woody angiosperms with intermediate densities (0.5–0.6 mg/mm3) associated with highest risk, whereas risk of impact was highest for conifers that coupled shade tolerance with drought intolerance. These results underscore the importance of identifying the relevant levels of biological organization and ecological interactions needed to develop accurate risk models for species that may arrive in novel ecosystems. [ABSTRACT FROM AUTHOR]

Dispersal of ground‐dwelling arthropods is understudied in forest ecosystems, which hinders understanding of effects of disturbances on population dynamics. The objective of the study was to quantify movement of ground‐dwelling arthropods in response to a factorial combination of canopy gap formation via girdling and understory vegetation removal, which was shown in a companion study to alter arthropod abundance and species richness. Arthropod movement was quantified using a self‐mark–capture technique where arthropods were marked as they crossed three concentric bands of different colored fluorescent powders located 3, 8, and 15 m from the center of 30 × 30 m experimental quadrats. The number of colors found on an individual was considered representative of dispersal such that the more colors detected, the more an individual moved. The likelihood that arthropods were marked with fluorescent powder and the number of colors detected differed among taxonomic groups. Most taxa were marked with one color and a high proportion of those individuals were collected adjacent to the band in which they were marked, suggesting limited dispersal. Canopy gaps and understory vegetation removal influenced movement of three taxa of highly mobile arthropods: Parajulidae and Paradoxosomatidae (detritivores), and Opiliones (scavengers). Opiliones were less likely to be marked with fluorescent powder in canopy gaps than under closed canopy in July, but more likely to be marked in August. Paradoxosomatidae were less likely to be marked in canopy gaps than under closed canopy in August, but their movement was unaffected in July. Parajulidae were more likely to be marked with fluorescent powders when understory vegetation was removed in July and August. Limited dispersal of most other ground‐dwelling arthropods suggests that these more sessile taxa may experience decreased survival and reproduction if they are unable to cope with environmental change in response to natural and anthropogenic disturbances. Understanding how disturbances mediate arthropod movement can inform biodiversity conservation strategies and sustainable forest management. [ABSTRACT FROM AUTHOR]

Management responses to invasive forest insects are facilitated by the use of detection traps ideally baited with species-specific semiochemicals. Emerald ash borer, Agrilus planipennis Fairmaire, is currently invading North American forests, and since its detection in 2002, development of monitoring tools has been a primary research objective. We compared six trapping schemes for A. planipennis over 2 yr at sites in four U.S. states and one Canadian province that represented a range of background A. planipennis densities, canopy coverage, and ash basal area. We also developed a region-wide phenology model. Across all sites and both years, the 10th, 50th, and 90th percentile of adult flight occurred at 428, 587, and 837 accumulated degree-days, respectively, using a base temperature threshold of 10°C and a start date of 1 January. Most trapping schemes captured comparable numbers of beetles with the exception of purple prism traps (USDA APHIS PPQ), which captured significantly fewer adults. Trapping schemes varied in their trap catch across the gradient of ash basal area, although when considering trap catch as a binary response variable, trapping schemes were more likely to detect A. planipennis in areas with a higher ash component. Results could assist managers in optimizing trap selection, placement, and timing of deployment given local weather conditions, forest composition, and A. planipennis density. [ABSTRACT FROM AUTHOR]

Assessing the ecological and economic impacts of non-native species is crucial to providing managers and policymakers with the information necessary to respond effectively. Most non-native species have minimal impacts on the environment in which they are introduced, but a small fraction are highly deleterious. The definition of 'damaging' or 'high-impact' varies based on the factors determined to be valuable by an individual or group, but interpretations of whether non-native species meet particular definitions can be influenced by the interpreter's bias or level of expertise, or lack of group consensus. Uncertainty or disagreement about an impact classification may delay or otherwise adversely affect policymaking on management strategies. One way to prevent these issues would be to have a detailed, nine-point impact scale that would leave little room for interpretation and then divide the scale into agreed upon categories, such as low, medium, and high impact. Following a previously conducted, exhaustive search regarding non-native, coniferspecialist insects, the authors independently read the same sources and scored the impact of 41 conifer-specialist insects to determine if any variation among assessors existed when using a detailed impact scale. Each of the authors, who were selected to participate in the working group associated with this study because of their diverse backgrounds, also provided their level of expertise and uncertainty for each insect evaluated. We observed 85% congruence in impact rating among assessors, with 27% of the insects having perfect inter-rater agreement. Variance in assessment peaked in insects with a moderate impact level, perhaps due to ambiguous information or prior assessor perceptions of these specific insect species. The authors also participated in a joint fact-finding discussion of two insects with the most divergent impact scores to isolate potential sources of variation in assessor impact scores. We identified four themes that could be experienced by impact assessors: ambiguous information, discounted details, observed versus potential impact, and prior knowledge. To improve consistency in impact decision-making, we encourage groups to establish a detailed scale that would allow all observed and published impacts to fall under a particular score, provide clear, reproducible guidelines and training, and use consensus-building techniques when necessary. [ABSTRACT FROM AUTHOR]

Insect pests cost billions of dollars per year globally, negatively impacting food crops and infrastructure, and contributing to the spread of disease. Timely information regarding developmental stages of pests can facilitate early detection and control, increasing efficiency and effectiveness. In 2018, the U.S. National Phenology Network (USA-NPN) released a suite of 'Pheno Forecast' map products relevant to science and management. The Pheno Forecasts include real-time maps and short-term forecasts of insect pest activity at management-relevant spatial and temporal resolutions and are based on accumulated temperature thresholds associated with critical life-cycle stages of economically important pests. Pheno Forecasts indicate, for a specified day, the status of the insect's target life-cycle stage in real time across the contiguous United States. The maps are available for 12 pest species including the invasive emerald ash borer (Agrilus planipennis Fairmaire [Coleoptera: Buprestidae]), hemlock woolly adelgid (Adelges tsugae Annand), and gypsy moth (Lymantria dispar Linnaeus [Lepidoptera: Erebidae]). Preliminary validation based on in-situ observations for hemlock woolly adelgid egg and nymph stages in 2018 indicated the maps to be ≥93% accurate depending on phenophase. Since their release in early 2018, these maps have been adopted by tree care specialists and foresters across the United States. Using a consultative mode of engagement, USA-NPN staff have continuously sought input and critique of the maps and delivery from end users. Based on feedback received, maps have been expanded and modified to include additional species, improved descriptions of the phenophase event of interest, and e-mail-based notifications to support management decisions. [ABSTRACT FROM AUTHOR]

A long‐standing goal of invasion biology is to identify factors driving highly variable impacts of non‐native species. Although hypotheses exist that emphasize the role of evolutionary history (e.g., enemy release hypothesis & defense‐free space hypothesis), predicting the impact of non‐native herbivorous insects has eluded scientists for over a century.Using a census of all 58 non‐native conifer‐specialist insects in North America, we quantified the contribution of over 25 factors that could affect the impact they have on their novel hosts, including insect traits (fecundity, voltinism, native range, etc.), host traits (shade tolerance, growth rate, wood density, etc.), and evolutionary relationships (between native and novel hosts and insects).We discovered that divergence times between native and novel hosts, the shade and drought tolerance of the novel host, and the presence of a coevolved congener on a shared host, were more predictive of impact than the traits of the invading insect. These factors built upon each other to strengthen our ability to predict the risk of a non‐native insect becoming invasive. This research is the first to empirically support historically assumed hypotheses about the importance of evolutionary history as a major driver of impact of non‐native herbivorous insects.Our novel, integrated model predicts whether a non‐native insect not yet present in North America will have a one in 6.5 to a one in 2,858 chance of causing widespread mortality of a conifer species if established (R2 = 0.91)Synthesis and applications. With this advancement, the risk to other conifer host species and regions can be assessed, and regulatory and pest management efforts can be more efficiently prioritized. [ABSTRACT FROM AUTHOR]

Phenological synchrony between herbivorous insects and host plants is an important determinant of insect distribution and abundance. Non-native insects often experience novel climates, photoperiods, and host plants. How critical time periods of insect life cycles coincide with—or diverge from—phenological windows of host plant suitability could affect invasion success and the dynamics of outbreaks. Larch casebearer is an invasive defoliator that has recently undergone anomalous outbreaks on eastern larch in North America. We conducted growth chamber, greenhouse, and field studies to quantify the spring phenological window for larch casebearer on eastern larch and importance of phenological synchrony for casebearer development and survival. We constructed degree-day models of spring activity for both species and investigated responses of casebearers to early and delayed activation relative to bud break. Both species had lower developmental thresholds of ~ 5 °C, but mean activation of casebearers occurred 245 degree-days after bud break by eastern larch. In addition to forcing temperatures, phenologies of eastern larch and casebearer larvae were significantly influenced by chilling and photoperiod, respectively. Larvae were robust to both starvation and delayed activation; days between larval activation and bud break (range: 0–58 days) had no influence on larval development and survival to adulthood. Disparate plant-insect responses to environmental cues and robustness of casebearers to changes in phenology result in a wide phenological window that likely has contributed to the insect's broad distribution in eastern North America. Changes in phenological synchrony, however, do not appear to have facilitated recent outbreaks of larch casebearer on eastern larch. [ABSTRACT FROM AUTHOR]

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The synchronization of insect and plant phenologies may impose ecological constraints on host specialization and the evolution of life histories.European pine sawfly Neodiprion sertifer (Geoffroy) feeds on mature foliage of Scots pine Pinus sylvestris L. during a limited temporal period in early spring and is univoltine despite the continual presence of this resource throughout the growing season. Reciprocal manipulation of host and insect phenologies demonstrated that larval performance was highest in mid‐April, with the window of host susceptibility closing rapidly thereafter.As the host phenology advanced, the foliar concentration of nitrogen, amino acids and soluble carbohydrates decreased, whereas that of terpenoids increased. As the foliar quality declined, larvae ate more in an attempt to compensate, although they were less efficient at converting consumed foliage to body mass.The phenological window for larval development began to reopen late in the growing season as the quality of mature foliage started to improve until it once again supported larval development during the next spring.Neodiprion sertifer must synchronize its life cycle with an ephemeral phenological window of host suitability that closes too early and reopens too late to permit a second generation. [ABSTRACT FROM AUTHOR]

In its native range in Asia, emerald ash borer (EAB; Agrilus planipennis Fairmaire) is a secondary colonizer of its coevolved hosts, including Manchurian ash (Fraxinus mandschurica Ruprecht). However, why larval performance is enhanced on stressed trees remains to be determined.We examined the mechanisms that may reduce the resistance of stressed Manchurian ashes. Trees in a common garden were girdled or left untreated as controls and both treatments were inoculated with EAB eggs. Larvae and bark tissue were harvested after feeding and larval performance so that the defensive mechanisms and nutritional quality of bark tissue could be assessed.Larval survival and mass was twice as high on girdled trees, although girdling had no effect on bark phenolics. The activity of two enzymes involved in wound repair and lignification (peroxidase and cinnamic alcohol dehydrogenase) was increased by girdling in bark tissue. Starch and total protein levels declined in girdled stems, although sugar content was unchanged. Total disulphide levels, a measure of protein oxidative damage, were increased by girdling, although no difference in lipid oxidative damage in ash phloem tissue was detected.Girdling ash increased larval performance even though it elevated some wound repair mechanisms and decreased some indices of plant nutritional quality. Other tree responses to girdling also were poor predictors of larval performance. It appears that mechanisms of stress‐induced variation in resistance of Manchurian ash to EAB differ from those that may explain interspecific variation in resistance. [ABSTRACT FROM AUTHOR]

Abstract: Emerald ash borer (Agrilus planipennis Fairmaire, EAB) is causing widespread ash (Fraxinus spp.) mortality as it invades North America and Eastern Europe. Resistance of its coevolved hosts, including Manchurian ash (Fraxinus mandshurica Rupr.), is considered to limit EAB outbreaks and ash mortality in its native Asia, although an understanding of resistance mechanisms is still developing. Such knowledge may facilitate breeding for resistance and management of EAB in its invaded ranges. In the present study, controlled egg inoculations were used to investigate resistance mechanisms impacting larval performance, as well as to characterize the effects of water and nutrient availability on inter‐ and intra‐specific variation in resistance phenotypes based on larval outcomes. Larval survival and growth rates were lower on coevolved Manchurian ash than on evolutionarily naïve white ash (Fraxinus americana L.). Water stress decreased tree growth and resistance of Manchurian ash to EAB, although it had little effect on resistance of the already highly susceptible white ash. High nutrient availability increased tree growth but had no effect on larval performance. These results show that the higher resistance of Manchurian ash to EAB is conferred by phloem traits that decrease larval performance, in addition to lower oviposition preference. [ABSTRACT FROM AUTHOR]

The growth of plants and insects occurs only above a minimum temperature threshold. In insects, the growth rate depends on the temperature above the threshold up to a maximum. In plants the growth rate above the threshold generally depends on the availability of sunlight. Thus, the relative growth rates of crops and insect phytophages are expected to differ between temperature regimes. We should therefore expect insect pest pressure at a location to change with climate warming. In this study, we used actual and simulated climate data developed for the IPCC 4th Assessment Report to drive linked plant and insect growth models to examine likely changes in insect-crop interaction. Projections of insect-crop dynamics through the 21st century suggest increases in pest pressure over much of the American Midwest, which could result in substantial increases in pesticide use to maintain productivity. Thus, climate warming could cause an increase in agriculture's carbon footprint. [ABSTRACT FROM AUTHOR]

Emerald ash borer (EAB; Agrilus planipennis Fairmaire) is an invasive wood-borer causing rapid, widespread ash tree mortality, formation of canopy gaps, and accumulation of coarse woody debris (CWD) in forest ecosystems. The objective of this study was to quantify the effects of canopy gaps and ash CWD on forest floor invertebrate communities during late stages of EAB-induced ash mortality, when the effects of gaps are predicted to be smallest and effects of CWD are predicted to be greatest, according to the model proposed by Perry and Herms 2016a. A 2-year study was conducted in forest stands that had experienced nearly 100% ash mortality in southeastern Michigan, USA, near where EAB first established in North America. In contrast to patterns documented during early stages of the EAB invasion, effects of gaps were minimal during late stages of ash mortality, but invertebrate communities were affected by accumulation and decomposition of CWD. Invertebrate activity-abundance, evenness, and diversity were highest near minimally decayed logs (decay class 1), but diverse taxon-specific responses to CWD affected community composition. Soil moisture class emerged as an important factor structuring invertebrate communities, often mediating the strength and direction of their responses to CWD and stages of decomposition. The results of this study were consistent with the predictions that the effects of CWD on invertebrate communities would be greater than those of canopy gaps during late stages of EAB-induced ash mortality. This research contributes to understanding of the cascading and long-term ecological impacts of invasive species on native forest ecosystems. [ABSTRACT FROM AUTHOR]

Emerald ash borer (EAB; Agrilus planipennis) is a devastating pest of ash ( Fraxinus spp.) in its invaded range in North America. Its coevolved Asian hosts are more resistant and less preferred for oviposition than susceptible North American species. We compared EAB oviposition preferences and bark and canopy volatile organic compound (VOC) emissions of resistant Manchurian ash and susceptible black ash, and examined relationships between VOC profiles and oviposition. In the field, black ash was highly preferred for oviposition while no eggs were laid on Manchurian ash, and we found clear differences in the VOC profiles of Manchurian and black ash. We detected 78 compounds emitted from these species, including 16 compounds that elicited EAB antennal activity in prior studies. Four compounds were unique to black and 11 to Manchurian ash. Emission rates of 14 canopy and 19 bark volatiles varied among the two species, including four previously reported as antennally active. Specifically, 7-epi-sesquithujene (bark) emissions were greater from black ash, while β-caryophyllene (canopy), linalool (bark), and α-cubebene (bark) were emitted at higher rates by Manchurian ash. No relationships were found between the emission rate of any single compound or group of compounds (e.g. monoterpenes) suggesting that preference may be based on complex profile combinations. This is the first study to directly compare VOCs of black and Manchurian ash as well as the first to examine bark- and canopy-specific VOCs. The unique bark and canopy VOC profiles of these two species implicates potentially important variation in VOCs between a closely related resistant and susceptible species that provides a foundation for future studies of host preferences of EAB. [ABSTRACT FROM AUTHOR]

Natural and anthropogenic disturbances alter canopy structure, understory vegetation, amount of woody debris, and the litter and soil layers in forest ecosystems. These environmental changes impact forest communities, including ground-dwelling invertebrates that are key regulators of ecosystem processes. Variation in frequency, intensity, duration, and spatial scale of disturbances affect the magnitude of these environmental changes and how forest communities and ecosystems are impacted over time. We propose conceptual models that describe the dynamic temporal effects of disturbance caused by invasive insects, wind, and salvage logging on canopy gap formation and accumulation of coarse woody debris (CWD), and their impacts on ground-dwelling invertebrate communities. In the context of this framework, predictions are generated and their implications for ground-dwelling invertebrate communities are discussed. [ABSTRACT FROM AUTHOR]

A major knowledge gap exists in understanding dispersal potential of ground-dwelling arthropods, especially in forest ecosystems. Movement of the ground-dwelling arthropod community was quantified using a novel mark-capture technique in which three different colored fluorescent powders in two separate mixtures were applied to the floor of a deciduous forest in concentric bands 3, 8, and 15 m from the center of 30 × 30 m experimental plots. The majority (67.1%) of ground-dwelling arthropods did not cross a colored band when fluorescents were mixed with protein powder in 2014. However, when mixed with sand in 2015, 77.3% of captured arthropods were marked with fluorescent powder, with the majority of individuals crossing one band (41.2%), suggesting limited dispersal by most individuals in the community. Only 2.8% and 15.0% of arthropods crossed all three bands in 2014 and 2015, respectively, which further indicates that individuals have limited dispersal. Responses were taxon-specific, and a high proportion of some arthropods such as millipedes and harvestmen crossed two or three bands. Limited dispersal by most individuals may have important implications for the structure and distribution of ground-dwelling arthropod communities, as well as their responses to natural or anthropogenic disturbances. Our results demonstrate the feasibility of this novel technique for self-marking and capturing individuals in the field to investigate dispersal of ground-dwelling arthropods. [ABSTRACT FROM AUTHOR]

Emerald ash borer (EAB) is an invasive beetle native to Asia that infests and kills ash ( Fraxinus spp.) in North America. Previous experiments indicated that larvae feeding on co-evolved, resistant Manchurian ash ( F. mandshurica) have increased antioxidant and quinone-protective enzyme activities compared to larvae feeding on susceptible North American species. Here, we examined mechanisms of host-generated oxidative and quinone-based stress and other putative defenses in Manchurian ash and the closely related and chemically similar, but susceptible, black ash ( F. nigra), with and without exogenous application of methyl jasmonate (MeJA) to induce resistance mechanisms. Peroxidase activities were 4.6-13.3 times higher in Manchurian than black ash, although both species appeared to express the same three peroxidase isozymes. Additionally, peroxidase-mediated protein cross-linking activity was stronger in Manchurian ash. Polyphenol oxidase, β-glucosidase, chitinase, and lipoxygenase activities also were greater in Manchurian ash, but only lipoxygenase activity increased with MeJA application. Phloem HO levels were similar and were increased by MeJA application in both species. Lastly, trypsin inhibitor activity was detected in methanol and water extracts that were not allowed to oxidize, indicating the presence of phenolic-based trypsin inhibitors. However, no proteinaceous trypsin inhibitor activity was detected in either species. In response to MeJA application, Manchurian ash had higher trypsin inhibitor activity than black ash using the unoxidized water extracts, but no treatment effects were detected using methanol extracts. Based on these results we hypothesize that peroxidases, lignin polymerization, and quinone generation contribute to the greater resistance to EAB displayed by Manchurian ash. [ABSTRACT FROM AUTHOR]

Emerald ash borer (Agrilus planipennis Fairmaire), an invasive wood-boring beetle native to Asia, has killed hundreds of millions of ash trees since its accidental introduction into North America, resulting in widespread formation of canopy gaps and accumulations of coarse woody debris (CWD) in forests. The objective was to quantify effects of canopy gaps and CWD caused by early stages of emerald ash borer-induced ash mortality, and their interaction on ground beetle assemblages. The impact of canopy gaps and CWD varied, as gaps affected beetle assemblages in 2011, while effects of CWD were only observed in 2012. Gaps decreased beetle activity-abundance, and marginally decreased richness, driving changes in species composition, but evenness and diversity were unaffected. Effects of the CWD treatment alone were minimal, but CWD interacted with the canopy treatment, resulting in an increase in activity-abundance of ground beetles in canopy gaps without CWD, and a marginal increase in species richness in canopy gaps with CWD. Although there were some initial changes in species composition, these were ephemeral, suggesting that ground beetle assemblages may be resilient to disturbance caused by emerald ash borer. This study contributes to our understanding of the cascading ecological impacts of biological invasions on forest ecosystems. [ABSTRACT FROM AUTHOR]

The emerald ash borer ( Agrilus planipennis; EAB) is causing widespread mortality of ash ( Fraxinus spp.) and climate change is altering habitats of tree species throughout large portions of North America. Black ash ( F. nigra), a moist-soil species common in the Northwoods of Minnesota, Wisconsin, and Michigan, USA, is under a double threat of losing habitat from climate change and near annihilation from EAB. Because black ash often occurs in nearly pure stands, planting non-ash species is a management strategy already underway or being planned for thousands of acres. Tools are needed to assist managers in prioritizing sites for early treatment and to select potential species to replace black ash. This study explores the implications of threats to black ash ecosystems using analyses of field data and models to assess both the threats to, and potential replacement species for, black ash in Minnesota. For our analysis we (1) assessed the status of ashes and co-occurring species in forest inventory plots throughout Minnesota; (2) modeled the risk of EAB attack for multiple years in Minnesota; (3) modeled potential impacts of climate change on tree species with current or potential future habitat in Minnesota; (4) evaluated species co-occurring with black ash in plots in Ohio and Michigan, southeast of Minnesota; and (5) synthesized these results to provide a classification for candidate replacement species, both from within Minnesota and from points farther south. Though this process is demonstrated for black ash in Minnesota, the elements to be considered and modeled would be similar for any other location with a pest or pathogen threat for a species which simultaneously faces a changing climate. [ABSTRACT FROM AUTHOR]

Eradication is the deliberate elimination of a species from an area. Given that international quarantine measures can never be 100% effective, surveillance for newly arrived populations of nonnative species coupled with their eradication represents an important strategy for excluding potentially damaging insect species. Historically, eradication efforts have not always been successful and have sometimes been met with public opposition. But new developments in our understanding of the dynamics of low-density populations, the availability of highly effective treatment tactics, and bioeconomic analyses of eradication strategies offer new opportunities for developing more effective surveillance and eradication programs. A key component that connects these new developments is the harnessing of Allee effects, which naturally promote localized species extinction. Here we review these developments and suggest how research might enhance eradication strategies. [ABSTRACT FROM AUTHOR]

We review the literature on host resistance of ash to emerald ash borer (EAB, Agrilus planipennis), an invasive species that causes widespread mortality of ash. Manchurian ash (Fraxinus mandshurica), which coevolved with EAB, is more resistant than evolutionarily naïve North American and European congeners. Manchurian ash was less preferred for adult feeding and oviposition than susceptible hosts, more resistant to larval feeding, had higher constitutive concentrations of bark lignans, coumarins, proline, tyramine and defensive proteins, and was characterized by faster oxidation of phenolics. Consistent with EAB being a secondary colonizer of coevolved hosts, drought stress decreased the resistance of Manchurian ash, but had no effect on constitutive bark phenolics, suggesting that they do not contribute to increased susceptibility in response to drought stress. The induced resistance of North American species to EAB in response to the exogenous application of methyl jasmonate was associated with increased bark concentrations of verbascoside, lignin and/or trypsin inhibitors, which decreased larval survival and/or growth in bioassays. This finding suggests that these inherently susceptible species possess latent defenses that are not induced naturally by larval colonization, perhaps because they fail to recognize larval cues or respond quickly enough. Finally, we propose future research directions that would address some critical knowledge gaps. [ABSTRACT FROM AUTHOR]

Protection of green ash trees (Fraxinus pennsylvanica Marshall) from the emerald ash borer (EAB), Agrilus planipennis Fairmaire, by soil applications of neonicotinoids (imidacloprid, clothianidin, and dinotefuran) was tested at five locations between 2005 and 2013. Application rate and spring versus fall application dates were evaluated in tests with neighborhood street trees and in one plantation of 65 ash trees. Insecticide treatments of ash trees at all five sites were initiated as the leading edge of the EAB invasion began to kill the first ash trees at each location. Trees were treated and evaluated at each site for 4 to 7 yr. Spring applications of imidacloprid were more efficacious than fall applications. Application rates of 0.8 g a.i./cm dbh or greater per year gave a higher level of protection and were more consistent than rates of 0.56 g a.i./cm dbh per year or less. The number of years between the first observation of canopy loss due to EAB and death of most of the control trees varied from three to seven years among test sites, depending on how many non-treated ash trees were nearby. [ABSTRACT FROM AUTHOR]

Emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is a non-native, wood-boring beetle that has caused widespread mortality of ash (Fraxinus Linnaeus (Oleaceae)) in eastern North America. During 2004–2007, we determined whether forest community composition and structure of black (F. nigra Marshall), green (F. pennsylvanica Marshall), and white (F. americana Linnaeus) ash stands influenced their susceptibility to EAB invasion in southeast Michigan, United States of America. There was no relationship between EAB-induced ash decline or percentage mortality and any measure of community composition (tree species diversity, stand/ash density, total basal area, or relative dominance of ash). There was also no relationship between measures of EAB impact (density of EAB signs, ash decline rating, percentage ash mortality, or percentage infested ash) and forest attributes (ash/total stand density, basal area, ash importance, or stand diversity). Decline and mortality of black ash advanced more rapidly than that of white and green ash. Percentage mortality of ash increased from 51% to 93% during 2004–2007. Distance from the epicentre of the invasion was negatively correlated with ash mortality, but this relationship dissipated over time. Stand composition data suggests that ash will be replaced by Quercus Linnaeus (Fagaceae), Acer Linnaeus (Sapindaceae), and Tilia Linnaeus (Malvaceae); such vegetation changes will irreversibly alter the structure and function of these forests. [ABSTRACT FROM PUBLISHER]

The emerald ash borer (EAB; Agrilus planipennis Fairmaire) is causing widespread mortality of ash ( Fraxinus spp.) in North America. To date, no mechanisms of host resistance have been identified against this pest. Methyl jasmonate was applied to susceptible North American and resistant Asian ash species to determine if it can elicit induced responses in bark that enhance resistance to EAB. In particular, phenolic compounds, lignin, and defense-related proteins were quantified, and compounds associated with resistance were subsequently tested directly against EAB larvae in bioassays with artificial diet. MeJA application decreased adult emergence in susceptible ash species, comparable to levels achieved by insecticide application. Concentration of the phenolic compound verbascoside sharply increased after MeJA application to green and white ash. When incorporated in an artificial diet, verbascoside decreased survival and growth of EAB neonates in a dose-dependent fashion. Lignin and trypsin inhibitors were also induced by MeJA, and analogs of both compounds reduced growth of EAB larvae in artificial diets. We conclude that the application of MeJA prior to EAB attack has the ability to enhance resistance of susceptible ash trees by inducing endogenous plant defenses, and report evidence that induction of verbascoside is a mechanism of resistance to EAB. [ABSTRACT FROM AUTHOR]

The "mother knows best" hypothesis states that adults should choose hosts for oviposition on which their offspring will best perform, maximizing their own fitness. It has been hypothesized that this preference-performance relationship for wood-boring insects is especially important because larvae are not able to switch hosts, although no study has examined oviposition choices for these insects. We examined oviposition preferences of the emerald ash borer, Agrito planipennis Fairmaire (Coleoptera: Buprestidae), in two common gardens, one on the campus of Wright State University in Dayton, OH, and the other at the Michigan State University Tollgate Research Farm in Novi, MI, by wrapping cheesecloth around ash trunks to assess passive oviposition patterns. We found that in both gardens, ash species native to North America, which are highly susceptible to the emerald ash borer, consistently received more ova than Manchurian ash, which is indigenous to Asia and more resistant to the emerald ash borer. Susceptible trees in the Novi garden received 93 times the number of ova and susceptible trees at the Wright State garden received up to 25 times the number of ova that were received by Manchurian ash in each of their respective gardens. Neither tree size nor vigor affected oviposition choice. There were also higher numbers of adult exit holes on North American than Manchurian ash in both common gardens. The observed oviposition preferences in this study align with patterns of adult feeding preference, ash host mortality, and exit hole numbers from other studies. These observations also suggest that oviposition preferences may contribute to interspecific patterns of host resistance and mortality. Collectively, our results demonstrate that the emerald ash borer prefers to oviposit on species on which its offspring will best perform, suggesting that there is strong selection for the ability to recognize host cues that predict better larval survival and performance. [ABSTRACT FROM AUTHOR]

Exotic herbivorous insects have drastically and irreversibly altered forest structure and composition of North American forests. For example, emerald ash borer ( Agrilus planipennis Fairmaire) from Asia has caused wide-scale mortality of ash trees ( Fraxinus spp.) in eastern United States and Canada. We studied the effects of forest changes resulting from emerald ash borer invasion on epigaeic or ground beetles (Coleoptera: Carabidae) along a gradient of ash dieback and gap sizes in southeastern Michigan. Ground beetles were sampled in hydric, mesic, and xeric habitats in which black ( Fraxinus nigra Marshall), green ( Fraxinus pennsylvanica Marshall), and white ( Fraxinus americana L.) ash were the most common species, respectively. During 2006-2007, we trapped 2,545 adult ground beetles comprising 52 species. There was a negative correlation between percent ash tree mortality in 2006 and catches of all beetles. Catches of Agonum melanarium Dejean (in 2006) and Pterostichus mutus (Say) (in 2006-2007) were negatively correlated with tree mortality and gap size, respectively. However, catches of Pterostichus corvinus Dejean were positively correlated with gap size in 2006. As ash mortality and average gap size increased from 2006 to 2007, catches of all beetles as well as P. mutus and Pterostichus stygicus (Say) increased (1.3-3.9 times), while species diversity decreased, especially in mesic and xeric stands. Cluster analysis revealed that beetle assemblages in hydric and mesic stand diverged (25 and 40%, respectively) in their composition from 2006 to 2007, and that hydric stands had the most unique beetle assemblages. Overall, epigaeic beetle assemblages were altered in ash stands impacted by emerald ash borer; however, these impacts may dissipate as canopy gaps close. [ABSTRACT FROM AUTHOR]

The invasive emerald ash borer ( EAB) beetle is a significant threat to the survival of North American ash. In previous work, we identified putative biochemical and molecular markers of constitutive EAB resistance in Manchurian ash, an Asian species co-evolved with EAB. Here, we employed high-throughput high-performance liquid chromatography with photodiode array detection and mass spectrometry ( HPLC-PDA- MS) to characterize the induced response of soluble phloem phenolics to EAB attack in resistant Manchurian and susceptible black ash under conditions of either normal or low water availability, and the effects of water availability on larval performance. Total larval mass per tree was lower in Manchurian than in black ash. Low water increased larval numbers and mean larval mass overall, but more so in Manchurian ash. Low water did not affect levels of phenolics in either host species, but six phenolics decreased in response to EAB. In both ashes, pinoresinol A was induced by EAB, especially in Manchurian ash. Pinoresinol A and pinoresinol B were negatively correlated with each other in both species. The higher accumulation of pinoresinol A in Manchurian ash after attack may help explain the resistance of this species to EAB, but none of the responses measured here could explain increased larval performance in trees subjected to low water availability. [ABSTRACT FROM AUTHOR]

Emerald ash borer (EAB; Agrilus planipennis) has killed millions of ash trees and threatens ash throughout North America, and long-term persistence of ash will depend on the potential for regeneration. We quantified ash demography, including mortality and regeneration, of Fraxinus americana (white ash), Fraxinus pennsylvanica (green ash), and Fraxinus nigra (black ash) in mixed hardwood forests near the epicenter of the EAB invasion in southeastern Michigan and throughout Ohio. Plots were established across a gradient of ash densities. Ash was the most important species in hydric sites, and ranked second among all species in mesic and xeric sites. In sites nearest the epicenter in Michigan, ash mortality exceeded 99 % by 2009, and few or no newly germinated ash seedlings were observed, leaving only an 'orphaned cohort' of established ash seedlings and saplings. As ash mortality increased, the number of viable ash seeds in soil samples decreased sharply, and no viable seeds were collected in 2007 or 2008. In Ohio sites farther from the epicenter, densities of new ash seedlings were much higher in plots with healthy ash trees compared to plots where trees had died. EAB was still present in low densities in Michigan and Ohio stands in 2012 where average mortality of ash was nearly 100 %. The future of ash at these sites will depend on the outcome of the dynamic interaction between the orphaned cohort of previously established ash seedlings and saplings and low density EAB populations. [ABSTRACT FROM AUTHOR]

Despite substantial increases in public awareness and biosecurity systems, introductions of non-native arthropods remain an unwelcomed consequence of escalating rates of international trade and travel. Detection of an established but unwanted non-native organism can elicit a range of responses, including implementation of an eradication program. Previous studies have reviewed the concept of eradication, but these efforts were largely descriptive and focused on selected case studies. We developed a Global Eradication and Response DAtabase ('GERDA') to facilitate an analysis of arthropod eradication programs and determine the factors that influence eradication success and failure. We compiled data from 672 arthropod eradication programs targeting 130 non-native arthropod species implemented in 91 countries between 1890 and 2010. Important components of successful eradication programs included the size of the infested area, relative detectability of the target species, method of detection, and the primary feeding guild of the target species. The outcome of eradication efforts was not determined by program costs, which were largely driven by the size of the infestation. The availability of taxon-specific control tools appeared to increase the probability of eradication success. We believe GERDA, as an online database, provides an objective repository of information that will play an invaluable role when future eradication efforts are considered. [ABSTRACT FROM AUTHOR]

Since its accidental introduction from Asia, emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), has killed millions of ash trees in North America. As it continues to spread, it could functionally extirpate ash with devastating economic and ecological impacts. Little was known about EAB when it was first discovered in North America in 2002, but substantial advances in understanding of EAB biology, ecology, and management have occurred since. Ash species indigenous to China are generally resistant to EAB and may eventually provide resistance genes for introgression into North American species. EAB is characterized by stratified dispersal resulting from natural and human-assisted spread, and substantial effort has been devoted to the development of survey methods. Early eradication efforts were abandoned largely because of the difficulty of detecting and delineating infestations. Current management is focused on biological control, insecticide protection of high-value trees, and integrated efforts to slow ash mortality. [ABSTRACT FROM AUTHOR]

Bronze birch borer (Agrilus anxius Gory) (Coleoptera: Buprestidae), a specialist wood-borer endemic to North America, is prone to periodic outbreaks that have caused widespread mortality of birch (Betula spp.) in boreal and north temperate forests. It is also the key pest of birch in ornamental landscapes. Amenity plantings have extended the distribution of birch in North America, for which we report an updated map. Life history and phenology also are summarized. Larvae feed primarily on phloem tissue of stems and branches, which can girdle and kill trees. Stressors such as drought, elevated temperature, and defoliation predispose trees to bronze birch borer colonization and trigger outbreaks, which implicates the availability of suitable host material in the bottom-up regulation of populations. Stress imposed by climate change may increase the frequency of outbreaks and alter the distribution of birch. Bronze birch borer has a diverse array of natural enemies, but their role in top-down population regulation has not been studied. There is substantial interspecific variation in resistance to this insect. North American species share a coevolutionary history with bronze birch borer and are much more resistant than Eurasian species, which are evolutionarily naive. Potential resistance mechanisms are reviewed. The high susceptibility of Eurasian birch species and climatic similarities of North America and Eurasia create high risk of widespread birch mortality in Eurasia if the borer was inadvertently introduced. Bronze birch borer can be managed in amenity plantings through selection of resistant birch species, plant health care practices, and insecticides. [ABSTRACT FROM AUTHOR]

The emerald ash borer ( Agrilus planipennis, EAB) is an invasive wood-borer indigenous to Asia and is responsible for widespread ash ( Fraxinus spp.) mortality in the U.S. and Canada. Resistance and susceptibility to EAB varies among Fraxinus spp., which is a result of their co-evolutionary history with the pest. We characterized constitutive phenolic profiles and lignin levels in the phloem of green, white, black, blue, European, and Manchurian ash. Phloem was sampled twice during the growing season, coinciding with phenology of early and late instar EAB. We identified 66 metabolites that displayed a pattern of variation, which corresponded strongly with phylogeny. Previously identified lignans and lignan derivatives were confirmed to be unique to Manchurian ash, and may contribute to its high level of resistance to EAB. Other compounds that had been considered unique to Manchurian ash, including hydroxycoumarins and the phenylethanoids calceolarioside A and B, were detected in closely related, but susceptible species, and thus are unlikely to contribute to EAB resistance of Manchurian ash. The distinct phenolic profile of blue ash may contribute to its relatively high resistance to EAB. [ABSTRACT FROM AUTHOR]

In managed settings, seedlings are often fertilized with the objective of enhancing establishment, growth, and survival. However, responses of seedlings to fertilization can increase their susceptibility to abiotic stresses such as drought. Seedlings acclimate to variation in soil resources by reallocating carbon among different physiological processes and compartments, such as above versus belowground growth, secondary metabolism, and support of ectomycorrhizal fungi (EMF). We examined the effects of nutrient and water availability on carbon allocation to above and belowground growth of river birch ( Betula nigra), as well as partitioning among root sugars, starch, phenolics, lignin, and EMF abundance. As nutrient availability increased, total plant biomass and total leaf area increased, while percent root biomass decreased. Root sugars, total root phenolics and EMF abundance responded quadratically to nutrient availability, being lowest at intermediate fertility levels. Decreased water availability reduced total leaf area and root phenolics relative to well-watered controls. No interactions between nutrient and water availability treatments were detected, which may have been due to the moderate degree of drought stress imposed in the low water treatment. Our results indicate that nutrient and water availability significantly alter patterns of carbon allocation and partitioning in roots of Betula nigra seedlings. The potential effects of these responses on stress tolerance are discussed. [ABSTRACT FROM AUTHOR]

Invasive species increasingly threaten ecosystems, food production, and human welfare worldwide. Hundreds of eradication programs have targeted a wide range of nonnative insect species to mitigate the economic and ecological impacts of biological invasions. Many such programs used multiple tactics to achieve this goal, but interactions between tactics have received little formal consideration, specifically as they interact with Alice dynamics. If a population can be driven below an Allee threshold, extinction becomes more probable because of factors such as the failure to find mates, satiate natural enemies, or successfully exploit food resources, as well as demographic and environmental stochasticity. A key implication of an Allee threshold is that the population can be eradicated without the need and expense of killing the last individuals. Some combinations of control tactics could interact with Allee dynamics to increase the probability of successful eradication. Combinations of tactics can be considered to have synergistic (greater efficiency in achieving extinction from the combination), additive (no improvement over single tactics alone), or antagonistic (reduced efficiency from the combination) effects on Allee dynamics. We highlight examples of combinations of tactics likely to act synergistically, additively, or antagonistically on pest populations. By exploiting the interacting effects of multiple tactics on Allee dynamics, the success and cost-effectiveness of eradication programs can be enhanced. [ABSTRACT FROM AUTHOR]

To better understand the diversity and ecology of indigenous arthropods at risk from the invasive emerald ash borer (Agrilus planipennis Fairmaire) in North American forests, saproxylic beetles (Insecta: Coleoptera) were reared from ash (Fraxinus sp.) limbs suspended in the canopy, ~10-17m above the ground, and from those placed on the ground in a mature mixed hardwood forest. In total, 209 specimens from 9 families and 18 species were collected from 30.0m² of limbs. The generalist cerambycid Neoclytus acuminatus (Fabricius) was the most commonly captured taxon, followed by an assemblage of four exotic ambrosia beetles dominated by Xylosandrus crassiusculus (Motschulsky). Two species largely or entirely restricted to ash, the buprestid Agrilus subcinctus Gory and the curculionid Hylesinus aculeatus (Say), were collected as well. Although there were no differences in beetle richness, abundance, or density between limb positions, community composition differed significantly. This can be largely attributed to phloem and wood-feeding species (i.e., Cerambycidae and Buprestidae) being more common in the suspended limbs and ambrosia beetles being more numerous on the forest floor. Possible explanations for these patterns are discussed. [ABSTRACT FROM AUTHOR]

The article presents a study on the impact of the growth regulator paclobutrazol and fertilization on the herbivore resistance and defensive chemistry of paper birch or Betula papyrifera and Austrian pine or Pinus nigra. The researchers performed the study in 48 physically isolated soil cells found at the Ohio Agricultural Research and Development Center in Wooster. They found that recommended rates of paclobutrazol had great growth-regulating impact on Austrian pine and paper birch.

The emerald ash borer (Agrilus planipennis) is an invasive wood-boring beetle that has killed millions of ash trees since its accidental introduction to North America. All North American ash species (Fraxinus spp.) that emerald ash borer has encountered so far are susceptible, while an Asian species, Manchurian ash (F. mandshurica), which shares an evolutionary history with emerald ash borer, is resistant. Phylogenetic evidence places North American black ash (F. nigra) and Manchurian ash in the same clade and section, yet black ash is highly susceptible to the emerald ash borer. This contrast provides an opportunity to compare the genetic traits of the two species and identify those with a potential role in defense/ resistance. We used Difference Gel Electrophoresis (DIGE) to compare the phloem proteomes of resistant Manchurian to susceptible black, green, and white ash. Differentially expressed proteins associated with the resistant Manchurian ash when compared to the susceptible ash species were identified using nano-LC-MS/MS and putative identities assigned. Proteomic differences were strongly associated with the phylogenetic relationships among the four species. Proteins identified in Manchurian ash potentially associated with its resistance to emerald ash borer include a PR-10 protein, an aspartic protease, a phenylcoumaran benzylic ether reductase (PCBER), and a thylakoid-bound ascorbate peroxidase. Discovery of resistancerelated proteins in Asian species will inform approaches in which resistance genes can be introgressed into North American ash species. The generation of resistant North American ash genotypes can be used in forest ecosystem restoration and urban plantings following the wake of the emerald ash borer invasion. [ABSTRACT FROM AUTHOR]

Bronze birch borer (Agrilus anxius Gory) is the key pest of birches (Betula spp.) in North America, several of which have been recommended for ornamental landscapes based on anecdotal reports of borer resistance that had not been confirmed experimentally. In a 20-yr common garden experiment initiated in 1979 in Ohio, North American birch species, including paper birch (Betula papyrifera Marshall), 'Whitespire' gray birch (Betula populifolia Marshall), and river birch (Betula nigra L.), were much more resistant to bronze birch borer than species indigenous to Europe and Asia, including European white birch (Betula pendula Roth), downy birch (Betula pubescens Ehrh. ), monarch birch (Betula maximowicziana Regel ), and Szechuan white birch (Betula szechuanica Jansson). Within 8 yr of planting, every European white, downy, and Szechuan birch had been colonized and killed, although 100% of monarch birch had been colonized and 88% of these plants were killed after nine years. Conversely, 97% of river birch, 76% of paper birch, and 73% Whitespire gray birch were alive 20 yr after planting, and river birch showed no evidence of colonization. This pattern is consistent with biogeographic theory of plant defense: North American birch species that share a coevolutionary history with bronze birch borer were much more resistant than naive hosts endemic to Europe and Asia, possibly by virtue of evolution of targeted defenses. This information suggests that if bronze birch borer were introduced to Europe or Asia, it could threaten its hosts there on a continental scale. This study also exposed limitations of anecdotal observation as evidence of host plant resistance. [ABSTRACT FROM AUTHOR]

We examined the extent to which three Fraxinus cultivars and a wild population that vary in their resistance to Emerald Ash Borer (EAB) could be differentiated on the basis of a suite of constitutive chemical defense traits in phloem extracts. The EAB-resistant Manchurian ash ( F. mandshurica, cv. Mancana) was characterized by having a rapid rate of wound browning, a high soluble protein concentration, low trypsin inhibitor activities, and intermediate levels of peroxidase activity and total soluble phenolic concentration. The EAB-susceptible white ash ( F. americana, cv. Autumn Purple) was characterized by a slow wound browning rate and low levels of peroxidase activity and total soluble phenolic concentrations. An EAB-susceptible green ash cultivar ( F. pennsylvanica, cv. Patmore) and a wild accession were similar to each other on the basis of several chemical defense traits, and were characterized by high activities of peroxidase and trypsin inhibitor, a high total soluble phenolic concentration, and an intermediate rate of wound browning. Lignin concentration and polyphenol oxidase activities did not differentiate resistant and susceptible species. Of 33 phenolic compounds separated by HPLC and meeting a minimum criterion for analysis, nine were unique to Manchurian ash, five were shared among all species, and four were found in North American ashes and not in the Manchurian ash. Principal components analysis revealed clear separations between Manchurian, white, and green ashes on the basis of all phenolics, as well as clear separations on the basis of quantities of phenolics that all species shared. Variation in some of these constitutive chemical defense traits may contribute to variation in resistance to EAB in these species. [ABSTRACT FROM AUTHOR]