Invasive Forest Pest Research Articles

Quantifying uncertainty in pest risk maps and assessments: adopting a risk-averse decision maker’s perspective

Pest risk maps are important decision support tools when devising strategies to minimize introductions of invasive organisms and mitigate their impacts. When possible management responses to an invader include costly or socially sensitive activities, decision-makers tend to follow a more certain (i.e., risk-averse) course of action. We presented a new mapping technique that assesses pest invasion risk from the perspective of a risk-averse decision maker.We demonstrated the method by evaluating the likelihood that an invasive forest pest will be transported to one of the U.S. states or Canadian provinces in infested firewood by visitors to U.S. federal campgrounds. We tested the impact of the risk aversion assumption using distributions of plausible pest arrival scenarios generated with a geographically explicit model developed from data documenting camper travel across the study area. Next, we prioritized regions of high and low pest arrival risk via application of two stochastic ordering techniques that employed, respectively, first- and second-degree stochastic dominance rules, the latter of which incorporated the notion of risk aversion. We then identified regions in the study area where the pest risk value changed considerably after incorporating risk aversion.While both methods identified similar areas of highest and lowest risk, they differed in how they demarcated moderate-risk areas. In general, the second-order stochastic dominance method assigned lower risk rankings to moderate-risk areas. Overall, this new method offers a better strategy to deal with the uncertainty typically associated with risk assessments and provides a tractable way to incorporate decision-making preferences into final risk estimates, and thus helps to better align these estimates with particular decision-making scenarios about a pest organism of concern. Incorporation of risk aversion also helps prioritize the set of locations to target for inspections and outreach activities, which can be costly. Our results are especially important and useful given the huge number of camping trips that occur each year in the United States and Canada.

Representing uncertainty in a spatial invasion model that incorporates human-mediated dispersal

Most modes of human-mediated dispersal of invasive species are directional and vector-based. Classical spatial spread models usually depend on probabilistic dispersal kernels that emphasize distance over direction and have limited ability to depict rare but influential long-distance dispersal events. These aspects are problematic if such models are used to estimate invasion risk. Alternatively, a geographic network model may be better at estimating the typically low likelihoods associated with human-mediated dispersal events, but it should also provide a reasonable account of uncertainties that could affect perception of its risk estimates. We developed a network model that assesses the likelihood of dispersal of invasive forest pests in camper-transported firewood in North America. We built the model using data from the U.S. National Recreation Reservation Service, which document visitor travel between populated places and federal campgrounds across the U.S. and Canada. The study area is depicted as a set of coarse-resolution map units. Based on repeated simulations, the model estimates the probability that each unit is a possible origin and destination for firewood-facilitated forest pest invasions. We generated output maps that summarise, for each U.S. state and Canadian province, where (outside the state or province) a camper-transported forest pest likely originated. Treating these output maps as a set of baseline scenarios, we explored the sensitivity of these “origin risk” estimates to additive and multiplicative errors in the probabilities of pest transmission between locations, as well as random changes in the structure of the underlying travel network. We found the patterns of change in the origin risk estimates due to these alterations to be consistent across all states and provinces. This indicates that the network model behaves predictably in the presence of uncertainties, allowing future work to focus on closing knowledge gaps or more sophisticated treatments of the impact of uncertainty on model outputs.

Recent advances in biological control of important native and invasive forest pests in China

In recent decades, China has suffered severe attacks by both native and invasive forest pests. We have carried out a series of research projects on biological control of these pests. The fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae) has been sustainably controlled by an effective gregarious pupal endoparasitoid, Chouioia cunea Yang (Chalcidoidea: Eulophidae), which is native to China, and spraying HcNPV virus against the pest’s larval stage. Pine wilt disease, caused by the pine wood nematode (Bursaphelenchus xylophilus (Steiner et Buhrer) Nickle) (Aphelenchida: Aphelenchidae), is currently the number one pest in China. The strategy for controlling the disease is to manipulate the nematode’s vector, Monochamus alternatus Hope (Coleoptera: Cerambycidae). We discovered that Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is the most important natural enemy in China pine forests. Mass rearing and release techniques were studied and developed. By releasing the parasitoid, 92.6% of the M. alternatus were parasitized in the first year. Meanwhile, three elaterid beetle species were found to prey on the larva of M. alternatus. The red turpentine beetle, Dendroctonus valens (LeConte) (Coleoptera:Scolytidae) was suppressed by a predator, Rhizophagus grandis Gyllenhal (Coleoptera: Rhizophagidae) introduced from Belgium and a total 3334ha. of pine forests were protected. The oak longhorned beetle, Massicus raddei (Blessig) (Coleoptera: Cerambycidae) is the number one pest in the northeast forests of China, where it damages trunk of oaks, mainly Quercus liaotungensis and Q. mongolicus. An integrated management technique was developed for controlling the longhorned beetle: a special black light was invented for trapping the adults; the parasitoid Sclerodermus pupariae Yang et Yao (Hymenoptera: Bethylidae) was released against young larvae; and the parasitoid Dastarcus helophoroides eggs and/or adults were released when the hosts were mature larvae and/or pupae. By applying the technique for five years in northeastern China oak forests, the oak longhorned beetle has been controlled to a large extent. The emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is native to eastern Asia, including China, and feeding by larvae damages ash trees. Natural enemies of the emerald ash borer were investigated and seven species were found in China, of which Spathius agrili Yang (Hymenoptera: Braconidae), Tetrastichus planipennisi Yang (Hymenoptera: Eulophiae), Sclerodermus pupariae Yang et Yao and Oobius agrili Zhang et Huang (Hymenoptera: Encyrtidae) are predominant and have high potential for biocontrol of the pest. The biology, behavior, ecology and mass rearing techniques of the parasitoids were studied.

Mapping ecological risks with a portfolio‐based technique: incorporating uncertainty and decision‐making preferences

AbstractAimGeographic mapping of risks is a useful analytical step in ecological risk assessments and in particular, in analyses aimed to estimate risks associated with introductions of invasive organisms. In this paper, we approach invasive species risk mapping as a portfolio allocation problem and apply techniques from decision theory to build an invasion risk map that combines risk and uncertainty in a single map product.LocationCanada.MethodsWe divide the study area into a set of spatial domains and treat each domain as an individual ‘portfolio’ with a unique distribution of the expected impacts of invasion. The risk of invasion is then mapped by finding nested ‘efficient’ portfolio sets that identify the geographic areas exhibiting the worst combinations of the estimated risk of invasion and the uncertainty in that estimate. For Canadian municipalities, we apply the approach to quantify the risk that a given location will receive invasive forest pests with commercial freight transported via the North American road network. We compare risk allocation techniques that employ the concepts of nested mean‐variance (M‐V) frontiers and second‐degree stochastic dominance.ResultsWhile both methods based on M‐V and the stochastic dominance principles identified similar areas of highest risk, they differed in how they demarcated moderate‐risk areas. Furthermore, they address uncertainty in different ways, treating it as a risk premium (in the case of nested M‐V frontiers) or producing risk‐averse delineations (in the case of stochastic dominance).Main conclusionsThe portfolio‐based approach offers a viable strategy for dealing with the typically wide variability in risk estimates caused by a lack of knowledge about a new invader. The methodology also provides a tractable way of incorporating decision‐making preferences into the final risk estimates and thus better aligns risk assessments with particular decision‐making scenarios about the organism of concern.

The Pheromone Frontalin and its Dual Function in the Invasive Bark Beetle Dendroctonus valens

The red turpentine beetle, Dendroctonus valens LeConte, is one of the most destructive invasive forest pests in China, having killed more than 6 million pines since its first outbreak in 1999. Little is known about D. valens pheromone biology and no aggregation pheromone has yet been identified. Analysis by gas chromatograph/mass spectrometer of volatiles collected from live beetles in China showed that female beetles produce frontalin and males do not. Olfactory assays in the laboratory showed that males were attracted to frontalin at a wide range of concentrations, whereas females were attracted to it at a narrow range of concentrations. In field trials, 3-carene, a monoterpene kairomone from a pine tree selected to host the beetles attracted both sexes, and when frontalin was added, the total number of beetles captured increased by almost 200%. However, increasing concentrations of frontalin significantly decreased the percentage of female beetles trapped. These results suggest a new role of frontalin as an aggregation pheromone in addition to a female-produced sex pheromone, which was previously shown in a North American population. The dual functions of the pheromone frontalin produced by D. valens females, as well as its ecological significance for overcoming host resistance, are discussed.

First insights into the genetic diversity of the pinewood nematode in its native area using new polymorphic microsatellite loci.

The pinewood nematode, Bursaphelenchus xylophilus, native to North America, is the causative agent of pine wilt disease and among the most important invasive forest pests in the East-Asian countries, such as Japan and China. Since 1999, it has been found in Europe in the Iberian Peninsula, where it also causes significant damage. In a previous study, 94 pairs of microsatellite primers have been identified in silico in the pinewood nematode genome. In the present study, specific PCR amplifications and polymorphism tests to validate these loci were performed and 17 microsatellite loci that were suitable for routine analysis of B. xylophilus genetic diversity were selected. The polymorphism of these markers was evaluated on nematodes from four field origins and one laboratory collection strain, all originate from the native area. The number of alleles and the expected heterozygosity varied between 2 and 11 and between 0.039 and 0.777, respectively. First insights into the population genetic structure of B. xylophilus were obtained using clustering and multivariate methods on the genotypes obtained from the field samples. The results showed that the pinewood nematode genetic diversity is spatially structured at the scale of the pine tree and probably at larger scales. The role of dispersal by the insect vector versus human activities in shaping this structure is discussed.

Estimates of Agrilus planipennis Infestation Rates and Potential Survival of Ash

The invasive forest pest, Agrilus planipennis (emerald ash borer, Coleoptera: Buprestidae), has caused significant mortality of ash (Fraxinus spp.) in southeastern Michigan, USA, where this pest is thought to have been originally introduced into North America. Phloem feeding by A. planipennis larvae leads to girdling of the host tree, which has resulted in the death of millions of ash trees in invaded landscapes. A survey of ash over a large geographic area was used to estimate numbers of dead and infested ash at a landscape scale within Indiana, Michigan and Ohio. Over 50 million ash trees infested with A. planipennis were estimated in the study area. This represented less than 20% of the ash trees at this broad landscape scale. We used an aerial survey with digital sketchmapping to identify individual and clusters of ash trees that were potentially alive in Oakland and Wayne Counties, Michigan, where A. planipennis is believed to have been active the longest. Diameters at breast height (DBH) and bark roughness were compared between live trees and the closest dead tree. Over 200 live trees were identified within five Huron-Clinton Metroparks, with 65% of these expressing signs and symptoms of A. planipennis attack. Trees that had succumbed to A. planipennis attack had significantly rougher bark than those trees that had survived, while DBH did not differ between the two groups. The probability of ash mortality increased with increasing bark roughness. Bark roughness provides insight into the potential survival of ash within forests. This case-control study, in addition to the estimates of infestation, establishes a baseline and the need to identify further individual and environmental characteristics that facilitate ash survival in the presence of A. planipennis.

Mutual interactions between an invasive bark beetle and its associated fungi

Interactions between invasive insects and their fungal associates have important effects on the behavior, reproductive success, population dynamics and evolution of the organisms involved. The red turpentine beetle (RTB), Dendroctonus valens LeConte (Coleoptera: Scolytinae), an invasive forest pest in China, is closely associated with fungi. By carrying fungi on specialized structures in the exoskeleton, RTB inoculates fungi in the phloem of pines (when females dig galleries for egg laying and when males join them for mating). After eggs hatch, larvae gregariously feed on the phloem colonized by the fungi. We examined the effects of five isolates of RTB associated fungi (two from North America, Leptographium terebrantis and L. procerum, and three from China, Ophiostoma minus, L. sinoprocerum and L. procerum) on larval feeding activity, development and mortality. We also studied the effects of volatile chemicals produced in the beetle hindgut on fungal growth. Ophiostoma minus impaired feeding activity and reduced weight in RTB larvae. Leptographium sinoprocerum, L. terebrantis and L. procerum did not dramatically influence larval feeding and development compared to fungi-free controls. Larval mortality was not influenced by any of the tested fungi. Hindgut volatiles of RTB larvae, verbenol, myrtenol and myrtenal, inhibited growth rate of all the fungi. Our results not only show that D. valens associated fungus, O. minus, can be detrimental to its larvae; but, most importantly, they also show that these notorious beetles have an outstanding adaptive response evidenced by the ability to produce volatiles that inhibit growth of harmful fungus.

Detection capacity, information gaps and the design of surveillance programs for invasive forest pests

Integrated pest risk maps and their underlying assessments provide broad guidance for establishing surveillance programs for invasive species, but they rarely account for knowledge gaps regarding the pest of interest or how these can be reduced. In this study we demonstrate how the somewhat competing notions of robustness to uncertainty and potential knowledge gains could be used in prioritizing large-scale surveillance activities. We illustrate this approach with the example of an invasive pest recently detected in North America, Sirex noctilio Fabricius. First, we formulate existing knowledge about the pest into a stochastic model and use the model to estimate the expected utility of surveillance efforts across the landscape. The expected utility accounts for the distribution, abundance and susceptibility of the host resource as well as the value of timely S. noctilio detections. Next, we make use of the info-gap decision theory framework to explore two alternative pest surveillance strategies. The first strategy aims for timely, certain detections and attempts to maximize the robustness to uncertainty about S. noctilio behavior; the second strategy aims to maximize the potential knowledge gain about the pest via unanticipated (i.e., opportune) detections. The results include a set of spatial outputs for each strategy that can be used independently to prioritize surveillance efforts. However, we demonstrate an alternative approach in which these outputs are combined via the Pareto ranking technique into a single priority map that outlines the survey regions with the best trade-offs between both surveillance strategies.

Antennal morphology and sensilla ultrastructure of Dendroctonus valens LeConte (Coleoptera: Curculionidae, Seolytinae), an invasive forest pest in China

Dendroctonus valens LeConte, an invasive forest pest, is highly dependent on its olfactory system for activities such as host seeking, mating, oviposition and population aggregation. The antennae are the primary olfactory organs in bark beetles. We describe four morphological types of sensilla on the antenna of D. valens: (1) 3 subtypes of sensilla trichodea located at the apex and lateral surface of the club. Sensilla trichodea types 1 and 3 were innervated by 5 and 13 dendrites, respectively. Sensilla trichode type 2 was not found dendrites in a lumen, (2) sensilla chaetica found on the scape and funicle and innervated by 7 dendrites, (3) a pair of sensilla basiconica distributed primarily on the three sensory bands, each innervated by 2 dendrites at the base, and (4) one fluted cone type of grooved peg dispersed throughout the sensory bands. The possible functions of these sensilla are discussed in relation to their morphology and ultrastructure.

Structured Decision-Making and Rapid Prototyping to Plan a Management Response to an Invasive Species

Abstract We developed components of a decision structure that could be used in an adaptive management framework for responding to invasion of hemlock woolly adelgid Adeleges tsugae on the Cumberland Plateau of northern Tennessee. Hemlock woolly adelgid, an invasive forest pest, was first detected in this area in 2007. We used a structured decision-making process to identify and refine the management problem, objectives, and alternative management actions, and to assess consequences and tradeoffs among selected management alternatives. We identified four fundamental objectives: 1) conserve the aquatic and terrestrial riparian conservation targets, 2) protect and preserve hemlock, 3) develop and maintain adequate budget, and 4) address public concerns. We designed two prototype responses using an iterative process. By rapidly prototyping a first solution, insights were gained and shortcomings were identified, and some of these shortcomings were incorporated and corrected in the second prototype. We found that objectives were best met when management focused on early treatment of lightly to moderately infested but relatively healthy hemlock stands with biological control agent predator beetles and insect-killing fungi. Also, depending on the cost constraint, early treatment should be coupled with silvicultural management of moderately to severely infested and declining hemlock stands to accelerate conversion to nonhemlock mature forest cover. The two most valuable contributions of the structured decision-making process were 1) clarification and expansion of our objectives, and 2) application of tools to assess tradeoffs and predict consequences of alternative actions. Predicting consequences allowed us to evaluate the influence of uncertainty on the decision. For example, we found that the expected number of mature forest stands over 30 y would be increased by 4% by resolving the uncertainty regarding predator beetle effectiveness. The adaptive management framework requires further development including identifying and evaluating uncertainty, formalizing other competing predictive models, designing a monitoring program to update the predictive models, developing a process for re-evaluating the predictive models and incorporating new management technologies, and generating support for planning and implementation.

Dispersal polymorphism in an invasive forest pest affects its ability to establish

Given the increasing number of biological invasions, there is a crucial need to identify life history traits that promote invasion. Invasiveness reflects capabilities for both establishment after introduction and spread following establishment. In this paper, we explore, via simulation, the interacting effects of dispersal and Allee effects on both invasion processes. Dispersal capability is a trait that has been widely recognized to facilitate invasions. However, dispersal dilutes local population densities in isolated populations and this could strengthen Allee effects, ultimately promoting extinction of invading populations. A spatially explicit, stochastic individual-based model was used to simulate dispersal, mating, and growth in isolated, newly arrived invading populations. We used the invasion of North America by the gypsy moth, Lymantria dispar, as a case study because: (1) a great amount of biological data on the species is available; (2) Allee effects caused by mate location failure are known to play an important role in its establishment and spread; and (3) a dispersal polymorphism has previously been identified (i.e., in some populations adult females are fully capable of flight, but in other populations females are not able to fly). We considered the introduction of a hypothetical number of eggs at a single location, originating from populations with varying female dispersal capabilities, and we then used simulation models to evaluate the population growth rate over two generations as well as spread distance. Nondispersing populations had the highest growth rates and inclusion of even limited dispersal capabilities caused population growth rates to be greatly diminished. The Allee threshold was 700 eggs for nondispersing populations and 1400 eggs for the long-distance dispersing populations. Thus, for an intermediate number of eggs initially introduced, nondispersing populations would most likely establish, whereas dispersing populations would likely become extinct. Spread distance increased linearly with the number of eggs initially introduced in both dispersing and nondispersing populations but rapidly reached a limit for nondispersing populations. Though species capable of long-distance dispersal may invade a larger area than nondispersing species, their growth rates are likely to be considerably lower, and eradication should be easier. Following these results, strategies for managing invasions should be adjusted for the interactions between Allee effects and dispersal.

Cost of potential emerald ash borer damage in U.S. communities, 2009–2019

Emerald ash borer ( Agrilus planipennis Fairmaire), a phloem-feeding beetle native to Asia, was discovered near Detroit, Michigan and Windsor, Ontario in 2002. As of March 2009, isolated populations of emerald ash borer (EAB) have been detected in nine additional states and Quebec. EAB is a highly invasive forest pest that has the potential to spread and kill native ash trees ( Fraxinus sp.) throughout the United States. We estimate the discounted cost of ash treatment, removal, and replacement on developed land within communities in a 25-state study area centered on Detroit using simulations of EAB spread and infestation over the next decade (2009–2019). An estimated 38 million ash trees occur on this land base. The simulations predict an expanding EAB infestation that will likely encompass most of the 25 states and warrant treatment, removal, and replacement of more than 17 million ash trees with mean discounted cost of $10.7 billion. Expanding the land base to include developed land outside, as well as inside, communities nearly double the estimates of the number of ash trees treated or removed and replaced, and the associated cost. The estimates of discounted cost suggest that a substantial investment might be efficiently spent to slow the expansion of isolated EAB infestations and postpone the ultimate costs of ash treatment, removal, and replacement.

A comparative analysis of engagement strategies for invasive alien species among Australia, Canada, New Zealand and United States: Case studies of forest pest insects

Australia, Canada, New Zealand and the United States operate some of the most advanced quarantine systems and cooperate on a quadrilateral scientific collaborative program in plant biosecurity. Through workshops, electronic information exchange and expert advice under the auspices of this program, country-specific engagement strategies for Invasive Alien Species (IAS) were obtained with the objective of comparing them and recommending risk management options to enhance effectiveness. The emphasis of this study was on invasive alien forest pest insects: Asian Gypsy Moth (Lymantria dispar), Asian Longhorned Beetle (Anoplophora glabripennis), Emerald Ash Borer (Agrilus planipennis) and the European Wood Wasp (Sirex noctilio). Comparative analysis of the data indicates that these strategies form a complex, non-linear system comprising two highly interdependent levels of decision making: a strategic level set around five strategic goals and implemented through 16 strategic approaches, and an operational level set around a highly-variable set of context-sensitive criteria. This paper will focus on the strategic level, providing innovative, country-specific approaches along with pest-specific best-management practices and success stories in relation to the selected case studies. It outlines the scope, guiding principles, goals, and approaches used by all four countries to engage with IAS, and provides an efficient resource allocation pattern as evidenced by success stories from these case studies.

Quantitative variation and biosynthesis of hindgut volatiles associated with the red turpentine beetle, Dendroctonus valens LeConte, at different attack phases

The red turpentine beetle (RTB), Dendroctonus valens LeConte, is a destructive invasive forest pest in China. For such tree-killing species, how to initiate a volatile-mediated mass attack is of great importance during the course of establishment. To understand the hindgut volatile production mechanism underlying mass attack initiated by RTB, coupled gas chromatography-mass spectrometry and 13C-labelled precursors were applied to explore the quantitative variation and biosynthesis of volatiles associated with RTB at different attack phases. Five previously described volatiles, trans-verbenol, myrtenol, cis-verbenol, myrtenal and verbenone, were identified and quantified from extracts of female and male hindguts, with the first two compounds as the major components and the latter three as minor constituents. In newly emerged females and males, only minute amounts of these compounds were detected. The quantity of volatiles from female adults significantly increased after they fed on bolts. Male adults also yielded larger quantities of volatiles after they joined females in galleries, which suggested that RTB males could accelerate the mass colonization on host trees. We also confirmed that RTB produced the five volatiles through oxidizing the major host monoterpene, alpha-pinene, but not synthesized de novo since products were labeled without 13C. The implication of this study in understanding the successful invasion of RTB is discussed.

Invasive forest pest surveillance: survey development and reliability

Worldwide, a large number of potential pest species are introduced to locations outside their native ranges; under the best possible prevention scheme, some are likely to establish one or more localized populations. A comprehensive early detection and rapid-response protocol calls for surveillance to determine if a pest has invaded additional locations outside its original area of introduction. In this manuscript, we adapt and spatially extend a two-stage sampling technique to determine the required sample size to substantiate freedom from an invasive pest with a known level of certainty. The technique, derived from methods for sampling livestock herds for disease presence, accounts for the fact that pest activity may be low at a coarse spatial scale (i.e., among forested landscapes) but high at a fine scale (i.e., within a given forested landscape). We illustrate the utility of the approach by generating a national-scale survey based on a risk map for a hypothetical forest pest species threatening the United States. These techniques provide a repeatable, cost-effective, practical framework for developing broad-scale surveys to substantiate freedom from non-native invasive forest pests with known statistical power.

A STATE-DEPENDENT MODEL FOR THE OPTIMAL MANAGEMENT OF AN INVASIVE METAPOPULATION

Management of invasive species involves choosing between different management strategy options, but often the best strategy for a particular scenario is not obvious. We illustrate the use of optimization methods to determine the most efficient management strategy using one of the most devastating invasive forest pests in North America, the gypsy moth (Lymantria dispar), as a case study. The optimization approach involves the application of stochastic dynamic programming (SDP) to a metapopulation framework with different infestation patch sizes, with the goal of minimizing infestation spread. We use a novel "moving window" approach as a way to address a spatially explicit problem without being explicitly spatial. We examine results for two cases in order to develop general rules of thumb for management. We explore a model with limited parameter information and then assess how strategies change with specific parameterization for the gypsy moth. The model results in a complex but stable, state-dependent management strategy for a multiyear management program that is robust even under situations of uncertainty. The general rule of thumb for the basic model consists of three strategies: eradicating medium-density infestations, reducing large-density infestations, and reducing the colonization rate from the main infestation, depending on the state of the system. With specific gypsy moth parameterization, reducing colonization decreases in importance relative to the other two strategies. The application of this model to gypsy moth management emphasizes the importance of managing based on the state of the system, and if applied to a specific geographic area, has the potential to substantially improve the efficiency and cost-effectiveness of current gypsy moth eradication programs, helping to slow the spread of this pest. Additionally, the approach used for this particular invasive species can be extended to the optimization of management programs for the spread of other invasive and problem species exhibiting metapopulation dynamics.

Emerald Ash Borer: Invasion of the Urban Forest and the Threat to North America’s Ash Resource

Abstract The emerald ash borer (EAB), a phloem-feeding beetle native to Asia, was discovered killing ash trees in southeastern Michigan and Windsor, Ontario, in 2002. Like several other invasive forest pests, the EAB likely was introduced and became established in a highly urbanized setting, facilitated by international trade and abundant hosts. Up to 15 million ash trees in urban and forested settings have been killed by the EAB. Quarantines in the United States and Canada restrict the movement of ash trees, logs, and firewood to prevent new introductions. Research studies are underway to assist managers leading eradication and containment efforts. Long-term efforts will be needed to protect ash in urban and forested settings across North America.