The emerald ash borer, Agrilus planipennis, is a beetle native to East Asia where it is considered a minor pest, preferentially attacking weakened or dying ash trees. It was first discovered in North ...America in 2002 and has since become one of the most serious invasive insect pests, killing millions of healthy ash trees in urban and forested settings. Similar damage is now occurring in the region of Moscow, Russia, which causes serious concern for Europe. In this paper, we review the current knowledge on A. planipennis in Asia and North America, provide new information on its occurrence in the region of Moscow and Eastern Russia and make recommendations for research and management strategies in Europe.
The emerald ash borer (EAB) is rapidly spreading throughout Eastern North America and devastating ecosystems where ash is a component tree. This rapid and sustained loss of ash trees has already ...resulted in ecological impacts on both terrestrial and aquatic ecosystems and is projected to be even more severe as EAB invades ash dominated wetlands of the western Great Lakes region. We propose a Special Issue that will address current research documenting ecological impacts of EAB in forest ecosystems, as well as management approaches to mitigate those impacts. Prospective authors are invited to contribute original researches to this Special Issue of Forests. Topics may include, but are not limited to: Managements of ash forests and potential replacements, nutrient and vegetation dynamics, greenhouse gas emissions and carbon sequestration and cycling, hydrologic impacts, and pre or post-infestation silvicultural approaches or management strategies.
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.
Background The Emerald ash borer (EAB), Agrilus planipennis, is an invasive phloem-feeding insect pest of ash trees. Since its initial discovery near the Detroit, US- Windsor, Canada area in 2002, ...the spread of EAB has had strong negative economic, social and environmental impacts in both countries. Several transcriptomes from specific tissues including midgut, fat body and antenna have recently been generated. However, the relatively low sequence depth, gene coverage and completeness limited the usefulness of these EAB databases. Methodology and Principal Findings High-throughput deep RNA-Sequencing (RNA-Seq) was used to obtain 473.9 million pairs of 100 bp length paired-end reads from various life stages and tissues. These reads were assembled into 88,907 contigs using the Trinity strategy and integrated into 38,160 unigenes after redundant sequences were removed. We annotated 11,229 unigenes by searching against the public nr, Swiss-Prot and COG. The EAB transcriptome assembly was compared with 13 other sequenced insect species, resulting in the prediction of 536 unigenes that are Coleoptera-specific. Differential gene expression revealed that 290 unigenes are expressed during larval molting and 3,911 unigenes during metamorphosis from larvae to pupae, respectively (FDR< 0.01 and log2 FC>2). In addition, 1,167 differentially expressed unigenes were identified from larval and adult midguts, 435 unigenes were up-regulated in larval midgut and 732 unigenes were up-regulated in adult midgut. Most of the genes involved in RNA interference (RNAi) pathways were identified, which implies the existence of a system RNAi in EAB. Conclusions and Significance This study provides one of the most fundamental and comprehensive transcriptome resources available for EAB to date. Identification of the tissue- stage- or species- specific unigenes will benefit the further study of gene functions during growth and metamorphosis processes in EAB and other pest insects.
Stejarul (Quercus robur L., 1753) și gorunul (Q. petraea (Matt) Liebl., 1784) sunt specii de arbori longevive, deosebit de valoroase sub aspect ecologic și economic, constituind componente importante ...ale pădurilor de foioase din zonele de câmpie și deal din România. Deși pădurile de stejari au o mare capacitate de refacere, în ultimele decenii acestea au fost afectate în numeroase rânduri de episoade de declin, având drept consecință volume mari de arbori uscați. În ultima perioadă s-a constatat creșterea frecvenței, precum și manifestarea diferită a acestora. Rolul important al speciilor de Agrilus în fenomenul de declin al stejarilor rezidă în faptul că acestea acționează în faza terminală a succesiunii de factori ce conduc la declin, împiedicând refacerea și provocând moartea arborilor. Cu toate acestea, nu sunt suficiente date privind infestările produse de speciile de Agrilus în România. Scopul acestei lucrări este de a prezenta o sinteză a informațiilor referitoare la caracteristicile speciilor de Agrilus care infestează stejarii și a simptomelor arborilor afectați de declin infestați cu Agrilus spp., pentru o mai bună înțelegere a relațiilor dintre aceste specii și declinul stejarilor, respectiv pentru o mai ușoară identificare a infestărilor produse.
AIM: Emerald ash borer Agrilus planipennis was identified in 2002 as the cause of extensive ash (Fraxinus spp.) decline and mortality in Detroit, Michigan, and has since killed millions of ash trees ...in the US and Canada. When discovered, it was not clear how long it had been present or at what location the invading colony started. We used dendrochronological methods to document the onset and progression of ash mortality and the spatio‐temporal dynamics of the invasion. Reconstructing the progression of ash mortality serves as a proxy to draw inferences about the colonization and spread of emerald ash borer in North America. LOCATION: Southeastern Michigan, USA. METHODS: We collected increment cores from dead, declining or non‐symptomatic ash trees on a systematic 4.8 × 4.8 or 2.4 × 2.4 km grid in 2004–2006. Geo‐referenced samples were cross‐dated to determine the earliest date emerald ash borer‐killed trees in each location. Interpolated dates of ash mortality were analysed to determine rates and patterns of emerald ash borer spread across the 1.5 million ha study area. RESULTS: We identified a location in southeastern Michigan where ash trees were killed by emerald ash borer as early as 1997. Rates of ash mortality subsequently progressed at 3.84 km year⁻¹ from 1998 to 2001 and then increased to 12.97 km year⁻¹ from 2001 to 2003 as satellite colonies coalesced with the primary infestation. From 1998 to 2003, new satellites formed at a rate of 7.4 per year, with average jump distances of 24.5 km. MAIN CONCLUSIONS: Emerald ash borer was likely established in southeastern Michigan by at least the early to mid‐1990s. Anthropogenic‐aided stratified dispersal and the coalescence of satellite colonies with the primary population resulted in biphasic range expansion, rapidly expanding the footprint of the invasion. Our reconstruction of the emerald ash borer invasion demonstrates this invaders’ remarkable capacity for population growth and spread.
Movement of invasive wood-boring insects in wood products presents a threat to forest health and a management challenge for public and private land managers. The goldspotted oak borer, Agrilus ...auroguttatus Schaeffer (Coleoptera: Buprestidae), is a new pest in San Diego and Riverside Cos., CA, believed to have been introduced on firewood. This beetle has caused elevated levels of oak mortality since 2002. From 2009-2011, we tested several sanitation methods, applicable to large and small land parcels, to reduce or prevent goldspotted oak borer emergence from infested oak wood. In most experiments, emergence of goldspotted oak borer adults from the positive controls demonstrated that the beetle could complete development in firewood-sized pieces of cut oak wood. In 2009, adult emergence from sun-exposed oak wood began and peaked 2- to 4-wks earlier at a low elevation site than at a high elevation site (late May to late June). However, there were no significant effects of elevation or host species on the emergence response of goldspotted oak borer by solarization treatment in this study. Solarization of infested wood with thick (6 mil) and thin (1 mil) plastic tarpaulins (tarps) did not significantly reduce emergence of adults despite recordings of greater mean and maximum daily temperatures in both tarped treatments and greater relative humidity in the thick-tarped treatment (all compared with nontarped controls). Grinding wood with a 3 double prime -minus screen ( less than or equal to 7.6 cm) significantly reduced goldspotted oak borer emergence compared with control treatments, and this was the best method for reducing adult emergence among those tested. In a separate grinding study, no adults emerged when wood was ground to 9 double prime -minus (22.9 cm), 2 double prime -minus (5.1 cm), or 1 double prime -minus (2.5 cm) screen sizes, but a low level of adult emergence from the positive controls limited any inferences from this experiment. Debarking cut wood pieces eliminated goldspotted oak borer emergence from the wood fraction, but adults emerged from the shaved bark and phloem.
•There has been extensive ash regeneration in EAB-invaded regions.•Regeneration is highest on plots with the longest invasion histories.•Seedling densities were generally unchanged between 2007 and ...2018.•Mortality is higher than recruitment on plots invaded for > 10 years.•Current trends indicate that few ashes are likely to survive to reproductive ages.
Non-native insects and pathogens can alter the composition and successional trajectories of forests and, in exceptional cases, drive their host trees functionally extinct. Emerald ash borer has killed millions of ash trees in its invaded range across eastern North America. Predicting the future ecological role of ash requires information on the extent of ash regeneration and recruitment in the wake of invasion. Variable levels of ash regeneration have been observed in stands invaded by emerald ash borer, although recruitment rates of young ash trees into the overstory remain unclear. Here, we used forest inventory data to quantify ash recruitment and regeneration across the eastern United States, and we linked these observed patterns to emerald ash borer invasion history. Inventory data from 2013-2018 indicate there has been extensive ash regeneration in invaded regions, totaling > 1,200 seedlings per ha in counties invaded in 2002–2006. Plots in counties with the longest invasion histories contained the highest densities of ash seedlings and saplings, likely due to the high densities of overstory ash in these areas prior to invasion by emerald ash borer. Seedling densities also remained generally unchanged between inventory periods ending in 2007 and 2018 irrespective of invasion history. Despite this widespread regeneration, ash trees in the smallest overstory class died at faster rates than they were recruited from seedlings or saplings, resulting in negative population trajectories on plots that have been invaded for more than ~ 10 years. This trend suggests that ash will continue to decline in abundance and may become functionally extinct across the invaded range of emerald ash borer. However, the future ecological role of ash will ultimately be determined by the iterative production and survival of ash seeds to reproductive ages in the presence of emerald ash borer populations, along with effective management practices.
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