Emerald Ash Borer Research Articles

A novel oviposition trap for studying the egg-laying behavior of emerald ash borer

A novel oviposition trap for studying the egg-laying behavior of emerald ash borer

Состояние посадок ясеня пенсильванского Fraxinus pennsylvanica Marsh в Московском регионе после инвазии ясеневой узкотелой златки Agrilus planipennis Fairmaire (Coleoptera, Buprestidae)

In 2017-2023 on the territory of Moscow region studied three types of plantings of Pennsylvania ash that survived the invasion of Agrilus planipennis in 2005-2012. All the trees damaged by the larvae A. planipennis. Most of the trees died (75%), the surviving trees remain the chronic ground of pests for twenty years. The surviving trees (25%) cropped, the assessment of their condition in 2017-2018 met the criterion of "weakened", in 2018-2023 – "severely weakened". The improvement in the condition of the trees in 2014-2018 replaced by a deterioration in 2021. Among the three types of plantings, the satisfactory condition of trees found in squares and multi–row plantings along streets, poor - in single-row plantings along streets. In the next decade most of the plantings along the streets degrade, other types of plantings remain. At the squares and parks of the center of the Moscow megalopolis, the trees partially restores the crown and partially overgrowing of old larval galleries on trunks. Damage by A. planipennis on multi-row plantings along highways provoked an outbreak of Leperesinus varius in 2006-2008. The synergy of A. planipennis and L. varius caused the rapid death of the Pennsylvania ash tree in the Moscow region. Trees trimmed to 1/3 of the crown and the "weakened" category live for at least 8 years, the "severely weakened" category – for at least 5 years. Removing from 1/3 to 2/3 of the crown is advisable only for trees of the "weakened" category. Removing more than 2/3 of the crown and topping with the removal of the top and skeletal branches leads to death of the tree. Keywords: GREEN ASH, EMERALD ASH BORER, HEALTH OF URBAN PLANTINGS

MelSPPNET—A self-explainable recognition model for emerald ash borer vibrational signals

IntroductionThis study aims to achieve early and reliable monitoring of wood-boring pests, which are often highly concealed, have long lag times, and cause significant damage to forests. Specifically, the research focuses on the larval feeding vibration signal of the emerald ash borer as a representative pest. Given the crucial importance of such pest monitoring for the protection of forestry resources, developing a method that can accurately identify and interpret their vibration signals is paramount.MethodsWe introduce MelSPPNET, a self-explaining model designed to extract prototypes from input vibration signals and obtain the most representative audio segments as the basis for model recognition. The study collected feeding vibration signals of emerald ash borer larvae using detectors, along with typical outdoor noises. The design of MelSPPNET considers both model accuracy and interpretability.ResultsExperimental results demonstrate that MelSPPNET compares favorably in accuracy with its similar non-interpretable counterparts, while providing interpretability that these networks lack. To evaluate the interpretability of the case-based self-explaining model, we designed an interpretability evaluation metric and proved that MelSPPNET exhibits good interpretability. This provides accurate and reliable technical support for the identification of emerald ash borer larvae.DiscussionWhile the work in this study is limited to one pest type, future experiments will focus on the applicability of this network in identifying other vibration signals. With further research and optimization, MelSPPNET has the potential to provide broader and deeper pest monitoring solutions for forestry resource protection. Additionally, this study demonstrates the potential of self-explaining models in the field of signal processing, offering new ideas and methods for addressing similar problems.

Modelling the potential range of Agrilus planipennis in Europe according to current and future climate conditions

Agrilus planipennis, the emerald ash borer, is a species native to East Asia that was accidentally introduced to North America and Eastern Europe. In North America, it is responsible for tremendous damage. In Europe, its range has quickly expanded from the east where it was introduced in 2003, and it threatens the species of the genus Fraxinus. We developed an ensemble modelling approach to model the potential range of A. planipennis according to current climate conditions and four scenarios of climate change: SSP1–2.6, SSP2–4.5, SSP3–7.0 SSP5–8.5 in the period 2041–2060. We used three algorithms; random forest, boosted regression trees and Bayesian additive regression trees with occurrence data from both native and invaded ranges. The results indicate that most of the European continent is climatically suitable for A. planipennis. In Western Europe, the northern limit of the range is located in the British Isles and southern Scandinavia. The projection of the models according to estimates of future climate conditions shows that climate suitability would mostly remain unchanged in 2041–2060. During that period, the potential range is expected to slightly shrink in the south, around the Mediterranean Basin, and expand at its northern limit. Our results confirm that A. planipennis is, and will remain, a major threat to forest and ornamental ash tree health across Europe.

Detection of Emerging Stress in Trees Using Hyperspectral Indices as Classification Features

This research presents a classification methodology for the detection of new or emerging stress in trees using indices derived from hyperspectral data and tests whether existing hyperspectral indices are effective when used as the classification features for this problem. We tested six existing indices—Water Band Index (WBI), Gitelson–Merzlyak B Index (GMb), Normalized Phaeophytization Index (NPQI), Combined Carotenoid/Chlorophyll Ratio Index (CCRI), Photochemical Reflectance Index (PRI), and Red-Edge Chlorophyll Index (CIre)—along with a seventh Test Index—generated as a composite of PRI and Cire—as classification features. Analysis was conducted using data collected from trees with and without emerald ash borer (EAB) infestation to develop a methodology that could be adapted to measure emerging stress from other pathogens or invasive pests in other tree species. Previous work has focused specifically on the identification of damage or stress symptoms caused by a specific pathogen. In this study, we adapted that work to develop a system of classification that can be applied to the identification of stress symptoms from a range of sources, measurable in trees based on spectral response and, in some cases, detectable prior to the onset of visible symptoms that can be measured through human observation. Our data indicate that existing indices derived from hyperspectral data are effective as classification features when measuring spectral responses indicative of emerging stress in trees.

Assessing the influence of climate on the growth of green ash trees from five Plant Hardiness Zones growing in a range-wide provenance test near the species’ northern range limit

Green ash is threatened with extirpation from emerald ash borer (EAB) attack. Because green ash has an extensive range, its restoration could require both breeding for EAB resistance and possible adaptation to a variety of environmental gradients. We assessed the growth and climate sensitivity of green ash from five Plant Hardiness Zones (PHZs) growing in a range-wide provenance test in Vermont. Although there tended to be greater growth among trees from the warmest PHZ (7), differences were rarely statistically distinguishable. For trees from all PHZs, growth was positively correlated with precipitation in the current year and negatively correlated with precipitation the year before (a possible legacy effect). Growth was negatively associated with temperature the year of ring formation but positively associated with temperatures the year before. Growth was often positively correlated with winter snow but was negatively associated with spring or fall snow for the warmest PHZs. Climate correlations for PHZ 3 were unusual in that (1) only positive correlations were detected, (2) no legacy effects were noted, and (3) despite being from the coldest region, no correlations with snow were found. Growth increased over time for the warmest PHZs during a period of simultaneous increases in temperature and precipitation.

A Time-Frequency Domain Mixed Attention-Based Approach for Classifying Wood-Boring Insect Feeding Vibration Signals Using a Deep Learning Model.

Wood borers, such as the emerald ash borer and holcocerus insularis staudinger, pose a significant threat to forest ecosystems, causing damage to trees and impacting biodiversity. This paper proposes a neural network for detecting and classifying wood borers based on their feeding vibration signals. We utilize piezoelectric ceramic sensors to collect drilling vibration signals and introduce a novel convolutional neural network (CNN) architecture named Residual Mixed Domain Attention Module Network (RMAMNet).The RMAMNet employs both channel-domain attention and time-domain attention mechanisms to enhance the network's capability to learn meaningful features. The proposed system outperforms established networks, such as ResNet and VGG, achieving a recognition accuracy of 95.34% and an F1 score of 0.95. Our findings demonstrate that RMAMNet significantly improves the accuracy of wood borer classification, indicating its potential for effective pest monitoring and classification tasks. This study provides a new perspective and technical support for the automatic detection, classification, and early warning of wood-boring pests in forestry.

Observations of reduced ET and persistent elevated water table beneath a riparian forest gap following emerald ash borer invasion and tree mortality

AbstractEmerald ash borer (EAB) (Agrilus planipennis Fairmaire), an invasive, phloem‐feeding beetle native to Asia, has killed millions of ash (Fraxinus spp.) trees in North America since it was detected in southeast Michigan in 2002. Consistently high mortality of black ash (Fraxinus nigra) and green ash (F. pennsylvanica) which often occur in riparian forests is a concern given their role in regulating soil moisture and shallow groundwater levels. We monitored and compared hydrologic processes in a riparian forest impacted by EAB invasion and an adjacent unimpacted riparian forest site in southwest Michigan. From 2018 to 2022, we recorded soil moisture, depth to groundwater and meteorological variables at 15‐min intervals throughout the growing season in a canopy gap following EAB‐caused ash mortality and in adjacent, unaffected forest in the Augusta Creek riparian zone. Groundwater contributions to evapotranspiration (ETG) were estimated using a groundwater level fluctuation (WLF) method. Significant differences in volumetric soil moisture content (16%–26% higher in the gap than forest), average depth to water (10 cm in the gap vs. 70 cm below land surface in the forest) and mean daily ETG (0.6 in the gap vs. 3.0 mm per day in the forest) persisted across four growing seasons. Within the gap, prolonged saturation of the near surface may be contributing to a shift from a forested riparian ecosystem to herb and sedge‐dominated wetland. These differences have implications for an array of riparian zone ecosystem services, a concern given the extent of ash mortality already sustained in much of eastern North America.

Forest Site and Stand Structure Affecting the Distribution of Emerald Ash Borer, Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae), in Eastern Ukraine

The Emerald ash borer (EAB), Agrilus planipennis Fairmaire, 1888 (Coleoptera: Buprestidae), an invasive phloem-boring beetle, was first detected in the Luhansk Region of Ukraine in 2019. Subsequently, it rapidly expanded its presence to encompass a significant portion of the Kharkiv region and the parks of Kyiv. Previous research has established that the climatic conditions in Luhansk and its neighboring regions are conducive to the EAB, and the absence of a host plant (Fraxinus sp.) does not act as a deterrent to the pest’s expansion in Ukraine. Recognizing the urgency of identifying infested trees, our current research aimed to identify the most attractive EAB forest subcompartments based on forest site conditions and stand structure. Utilizing the MaxEnt model, we achieved an average performance in predicting the potential distribution of the EAB (AUC = 0.842). The six most impactful variables, contributing to 88.2% of the model, include “age of trees, years”, “area of forest subcompartment, ha”, “mean height of trees, m”, “proportion of Fraxinus excelsior in the stand composition, %”, “hygrotope index (humidity level), point”, and “number of neighboring-non-forest subcompartments”. Most likely, EAB occurrence is expected in the driest forest site conditions; the well-lit and warmed-up parts of stands, in particular; small subcompartments surrounded by non-forest landscapes; and forest shelter belts near roads and fields. However, the data obtained can be considered preliminary. To enhance the accuracy of our forecasting, it may be imperative to consider data on road localization, along which the pest can spread passively, as well as dominant wind speed.

Long-term effects of a tornado: Impacts on woody native vegetation and invasive Amur honeysuckle (Lonicera maackii) in an urban forest.

As tornados become increasingly common with global climate change, recovery of the woody vegetation in temperate forests is imperative to maintain an intact ecosystem. In many urbanized landscapes, invasive species are also increasing and could interfere with natural recovery from environmental disturbance. We quantified the impact and 17-year recovery from a major tornado in a temperate deciduous forest. We used vegetational surveys in southwestern Ohio at the Harris M. Benedict Nature Preserve, where approximately a third of this site was damaged by a tornado in 1999. Plots were established in the tornado-damaged area and the nearby undisturbed forest to examine forest recovery of trees/saplings, shrubs and vines, and tree seedlings during 2003, 2006, 2010, and 2016/2017. The number of tree saplings, shrubs, and vines increased immediately after the tornado, but then declined by 2010, relative to the undisturbed forest. Forest tree recruitment was lower in tornado-damaged sites with fewer tree seedlings, but more saplings. Tree diversity was also affected by Agrilus planipennis (Emerald Ash borer) which targeted native ash trees within this time period. Despite an initial increase in shrubs and vines in the damaged area, the diversity and density of shrubs approached equality in both sites by 2016. Most shrubs in both sites were the invasive Lonicera maackii (Amur honeysuckle). In tornado sites, honeysuckle thinned out over time, leaving larger shrubs with greater mean basal diameter compared to the undisturbed forest. Other woody invasive species were also more prevalent in the damaged area, but increased in number in both locations by 2017. The forest has the capability to begin to recover from the initial tornado, but its future composition may differ from its initial trajectory due to invasive species, loss of ash trees, and anthropogenic impacts within the urban landscape.

Spread management priorities to limit emerald ash borer (Agrilus planipennis) impacts on United States street trees

AbstractThe invasive emerald ash borer (Agrilus planipennis) causes damage to street trees which is estimated to reach US$ 900 million over the next 30 years. Although millions of dollars are spent annually to control this species, spatiotemporal management plans are often based on rules of thumb that ignore future pest dispersal. Here, we reveal an optimal management strategy to protect urban trees in North America from A. planipennis. To achieve this, we embedded a pest dispersal model within a mixed integer programming framework. We discovered that optimized strategies consistently outperformed those based on rules of thumb, potentially resulting in the protection of an additional nearly 1 million street trees and savings of $ 629 million. Critically, the best management strategies always relied on quarantines and biological control (constituting 98–99% and 1–2% of the project budget, respectively), in contrast with current practices, where federal spending has been diverted to biological control. Our findings serve to inform future pest control efforts and can help protect many more trees from this invasive species.

Conservation of Green and White Ash Germplasm Using the Cryopreservation of Embryogenic Cultures

Green ash (Fraxinus pennsylvanica) and white ash (F. americana) populations are currently experiencing major declines across their native ranges in North America due to infestation by the exotic insect pest emerald ash borer (Agrilus planipennis). The development of a reliable method for the long-term storage of green and white ash germplasm in the form of embryogenic cultures using cryopreservation would be a considerable aid to ash conservation efforts. We compared recovery percentages of cryopreserved green and white ash embryogenic cultures using vitrification versus slow cooling methods. Three Plant Vitrification Solution 2 (PVS2) exposure durations (40, 60, and 80 min) for vitrification and three DMSO concentrations (5%, 10%, and 15%) for slow cooling were tested for their effects on the percentage of cultures that regrew following cryostorage. Vitrification resulted in a higher overall culture recovery percentage (91%) compared to cultures that were cryostored using the slow cooling approach (39%), and a more rapid initiation of regrowth (5 days versus 2–3 weeks) resulted. Recovery from cryostorage by cultures using the slow cooling approach varied significantly (p < 0.05) between experiments and with genotype (p < 0.05). The recovery of vitrified tissue from cryostorage did not vary with genotype, species, or PVS2 exposure duration (p > 0.05). The vitrification cryopreservation protocol provides a reliable and versatile alternative to the traditional slow cooling method, strengthening our ability to preserve valuable ash germplasm for conservation and restoration.

The lichen genus <i>Rinodina</i> (Physciaceae) in New Brunswick, Canada

Fifteen species of the crustose lichen genus Rinodina are confirmed in New Brunswick, Canada. We report four corticolous species, Rinodina pachysperma, Rinodina populicola, Rinodina septentrionalis, and Rinodina tenuis, and the saxicolous Rinodina tephraspis in the province for the first time. A previous report of Rinodina granuligera is based on a specimen that we have re-identified as Rinodina cinereovirens. We note distinguishing characteristics, habitats, substrata, relative abundance, and biogeographic relationships of each species and provide an identification key and distribution maps. The most frequently occupied phorophytes (tree substrata) are Sugar Maple (Acer saccharum), Yellow Birch (Betula alleghaniensis), and Eastern White Cedar (Thuja occidentalis). Some species are closely associated with particular habitats, phorophytes, or both. For example, we found R. pachysperma only in floodplain forests dominated by Silver Maple (Acer saccharinum), and R. tenuis only on Eastern White Cedar in wet cedar-dominated stands. In contrast, we recorded Rinodina freyi on numerous phorophyte species in a relatively wide range of habitats. Other than Eastern White Cedar and Balsam Fir (Abies balsamea), conifers are rarely colonized by Rinodina species in New Brunswick. Most Rinodina species are probably not currently of conservation concern in the province. However, R. cinereovirens is known from only two collections, one dating from 1902. The other, from 2007, was on Black Ash (Fraxinus nigra) in a swamp forest next to an active peat-mining operation. The expected devastation of ash species by the invasive Emerald Ash-borer (Agrilus planipennis) is a further threat to this occurrence and to any lichens for which ash may be an important phorophyte.

Efficacy of trapping protocols for Agrilus jewel beetles: a multi-country assessment

The genus Agrilus is one of the most diverse insect genera worldwide. The larval feeding activity causes extensive damage in both forests and orchards. In addition, more than 30 species have been introduced outside their native range so far, including the emerald ash borer Agrilus planipennis Fairmaire. Thus, the availability of efficient trapping protocols for early detection of Agrilus species at entry points is of utmost importance. In this study we tested whether trapping protocols developed for surveillance of A. planipennis in North America were also effective for other Agrilus species. In particular, through a multi-country assessment we compared the efficacy of detecting Agrilus species on: (i) green glue-coated prism traps vs. green Fluon-coated multi-funnel traps when baited with the green leaf volatile (Z)-3-hexenol or left unbaited; and (ii) green multi-panel traps vs. green multi-panel traps baited with dead adult Agrilus beetles (decoys). A total of 23,481 individuals from 45 Agrilus species were caught. Trap design significantly affected both species richness and abundance of Agrilus species in several of the countries where the trapping experiments were carried out, and green prism traps outperformed green multi-funnel traps in most cases. On the contrary, the addition of a (Z)-3-hexenol lure or dead adult beetle decoys on to traps did not improve trap catches. Our study highlights that reliable trap models to survey Agrilus species are already available, but also that there is the clear need to further investigate chemical ecology of Agrilus species to develop semiochemical lures that can improve detection efficacy.

Enhancing Buprestidae monitoring in Europe: Trap catches increase with a fluorescent yellow colour but not with the presence of decoys.

This study investigated the efficacy of various traps differing in colour (green or yellow), presence or absence of decoys (dead Agrilus planipennis) or design (commercial MULTz or multifunnel traps, and homemade bottle- or fan-traps) for monitoring European Buprestidae in deciduous forests and pear orchards. Over two years, we collected 2220 samples on a two-week basis from 382 traps across 46 sites in Belgium and France. None of the traps proved effective for monitoring Agrilus sinuatus in infested pear orchards (17 specimens captured in 2021, 0 in 2022). The decoys did not affect the catch rates whatever the trap model, colour, buprestid species or sex. The fluorescent yellow traps (MULTz and yellow fan-traps) tended to be more attractive than the green traps (green fan-traps and, to a lower extent, multifunnel green traps). Most Agrilus species showed similar patterns in mean trap catches, with the exception of Agrilus biguttatus, which had the largest catches in the green multifunnel traps. Finally, we observed a high variation in catch rates between localities: the site explained 64% of the catches variance, while the tree within the site and the type of trap explained only 6-8.5% each. In many sites, we captured very few specimens, despite the abundance of dying mature trees favourable to the development of Buprestidae. For the early detection of non-native Buprestidae, it therefore seems essential to maximise the number of monitoring sites. Due to their cost-effectiveness, lightweight design, and modularity, fan-traps emerged as promising tools for buprestid monitoring. The study's findings extend beyond European fauna, as a preliminary trial in Canada suggested that yellow fan-traps could also improve captures of non-European buprestid species and catch species of interest such as Agrilus bilineatus (a species on the EPPO A2 list of pests/pathogens recommended for regulation in the EU).

Analysis of the phytosanitary risk of the pest Agrilus planipennis Fairmaire, 1888 for tree species in Bulgaria

Analysis of the phytosanitary risk of the pest Agrilus planipennis Fairmaire, 1888 for tree species in Bulgaria

Parasitoid-induced changes in metabolic rate and feeding activity of the emerald ash borer (Coleoptera: Buprestidae): implications for biological control

Parasitoid-host interactions form the foundation of biological control strategies against many agriculture and forest insect pests. The emerald ash borer (EAB), Agrilus planipennis (Coleoptera: Buprestidae), is a serious invasive pest of ash (Fraxinus spp.) trees in North America. Tetrastichus planipennisi (Hymenoptera: Eulophidae) is a gregarious, koinobiont endoparasitoid, attacking late (3rd to 4th) instars of EAB larvae, which feed in the live phloem of ash trunks or branches, making serpentine-like galleries filled with larval frass. In the present study, we tested the hypothesis that T. planipennisi regulates the host metabolism and feeding activity to optimize its offspring development and fitness. We first compared the respiration rate of parasitized and unparasitized host larvae at different times after parasitism, and then measured feeding activity of both parasitized and unparasitized host larvae inside their feeding galleries. Although parasitized host larvae increased metabolic rate and feeding activity in the first few days of parasitism, T. planipennisi parasitism induced an overall reduction of the metabolic rate and decrease in feeding activity of parasitized host larvae over their development period. In addition, there was a negative relationship between feeding activity of parasitized hosts and brood sizes of the parasitoid progeny—i.e., the more parasitoid progeny a host larva received, the less feeding activity the host had. These findings suggest that T. planipennisi has limited ability to optimize its offspring development and fitness through regulations of the host metabolism and feeding activity and its parasitism reduces feeding damage of parasitized EAB larvae to infested ash trees.

Positive association between emerald ash borer residence time and accumulation of invasive plants

AbstractInvasive forest pests can affect the composition and physical structure of forest canopies that may facilitate invasion by non‐native plants. However, it remains unclear whether this process is generalizable across invasive plant species at broad spatial scales, and how other landscape characteristics may simultaneously facilitate non‐native plant invasion. Here, we assembled a dataset of over 3000 repeatedly measured forest plots and quantified the impact of emerald ash borer (EAB, Agrilus planipennis) residence time, land cover, and forest structure on the accumulation and coverage of invasive plants. We show plots in counties with longer EAB residences tended to accumulate more invasive plants than plots with shorter EAB residences. On average, nearly half of the plots with ash (Fraxinus spp.) in counties with EAB accumulated an additional 0.48 invasive plant species over the 5‐ to 6‐year resample interval compared to plots with ash in counties without EAB at the time of sampling. Increases in invasive species coverage were also evident in counties with EAB—although residence time did not have a strong effect, while forest gap fraction and vertical complexity were each negatively associated with increased coverage. This work has implications for understanding how invasive forest pests can facilitate the spread of non‐native plants.

Testing the heat treatment dose for Agrilus planipennis (Coleoptera: Buprestidae) prepupae using the Humble water bath.

The lethal heat treatment dose (time and temperature) for the prepupal life stage of Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), emerald ash borer (EAB), was determined through an in vitro application using a carefully calibrated heat treatment apparatus. The lethal and sublethal effects of heat on A. planipennis prepupae were assessed through a ramped heat delivery application, simulating industrial kilns and conventional heat chamber operations, for treatments combining target temperatures of 54 °C, 55 °C, and 56 °C, and exposure durations of 0 min (i.e., kiln temperature ramp only), 15 min, or 30 min. Prepupal EAB larvae did not survive exposure to 56 °C for 15 min or longer, or to 55 °C for 30 min. Sublethal effects were observed for all other treatments. Sublethal effects included delayed development and failure to complete the pupal and adult life stages.

Tree Condition and Analysis Program – Detecting Forest Disturbance at the Tree Level across the Contiguous United States with High Resolution Imagery

Abstract Effective management of forest insects and diseases requires detection of abnormal mortality, particularly among a single species, sufficiently early to enable effective management. Remote detection of individual trees crowns requires a spatial resolution not available from satellites such as Landsat or Sentinel-2. In the United States, there are currently few operational systems capable of effectively and affordably detecting and mapping tree mortality over broad landscapes using high-resolution imagery. Here, we introduce the Tree Condition and Analysis Program (TreeCAP), an open-source system that uses freely available imagery from the National Agriculture Imagery Program (NAIP) to create maps of tree condition (healthy or damaged). We demonstrate the potential applications of TreeCAP in four study sites: (1) beetle-killed pines in California, (2) emerald ash borer progression in Wisconsin, (3) hemlock wooly adelgid mortality in Pennsylvania, and (4) drought damage in Texas. We achieved an average overall accuracy of 87% across all study sites.