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AbstractThe emerald ash borer (EAB), Agrilus planipennisFairmaire (Coleoptera: Buprestidae) is a very serious invasive pest in North America, causing extremely high levels of mortality to ash trees (FraxinusLinnaeus, Oleaceae) in the United States of America and Canada. Knowledge of buprestid chemical ecology is sparse, but the appearance of EAB in North America and its devastating ecological and economic impacts, particularly in the urban environment, have provided an opportunity to study the semiochemistry, natural history, and ecology of this buprestid in detail. This review will summarise the chemical ecology of EAB to date, discussing studies on semiochemistry, natural history, and behaviour with respect to host and mate finding that have identified several female-produced pheromone components (contact and sex pheromones), and attractive host kairomones. Earlier reviews focused on studies of attractive host volatiles with respect to development of a trapping system and visual and contact phenomena in EAB mate finding. This has led to the development of an efficient trapping system for EAB, with attempts to optimise the range of variables in trap protocols, combining pheromone components, release rates, and combinations with host kairomones, as well as trap type, placement, height, and colour being taken into account.

AbstractAgrilus planipennis(Coleoptera: Buprestidae), is causing extensive mortality of ash (FraxinusLinnaeus; Oleaceae) in North America. Once detected in an area, resource managers require methods to obtain estimates that could improve management decisions. We studied the within-crown and within-branch distribution and abundance of A. planipennisfeeding galleries by sampling 3-m-long branches from asymptomatic urban ash trees and subdividing each branch into 12 sections of 25 cm each. We found galleries in all 12 sections of some, but not all, branches. Section was a significant source of variation in A. planipennisgallery density/m2of branch surface area. A comparison of predictive power and efficiency of estimates for samples of increasing length, and for samples of the same length but consisting of different combinations of sections, revealed that those based on the two basal 25-cm sections of a branch from the lower-crown or mid-crown of an asymptomatic tree were less accurate and precise than those based on more sections, but were the most cost effective. Whittling more sections per branch, irrespective of the combinations of branch sections per length, improved predictive power but reduced cost effectiveness. We also observed that crown level was not important, and aspect was only marginally so, when estimating gallery abundance per sampled branch.

AbstractPhasgonophora sulcataWestwood (Hymenoptera: Chalcididae) is a North American parasitoid now using Agrilus planipennisFairmaire (Coleoptera: Buprestidae) as a novel host, and may prove useful in biocontrol. Unfortunately, information is lacking regarding mating and the presence of pheromones, which may be important when attempting to exploit this parasitoid within a management context. Herein we used olfactometer assays and behavioural observations to determine the courtship and mating sequences of P. sulcata.A significantly higher proportion of males oriented towards females over the control arm containing filtered air in an olfactometer regardless of the age classes of females or males examined. We also observed four pre-copulatory behaviours that were consistent in all mating pairs. Our results indicate that courtship may be mediated by male perception of female-produced pheromones. Understanding the courtship sequence may be useful in rearing laboratory populations, while the putative pheromones may be useful in detection and retention of P. sulcatapopulations.

AbstractMonochamol (2-undecyloxy-1-ethanol) is a male-produced aggregation pheromone for several MonochamusDejean (Coleoptera: Cerambycidae) species. We conducted trapping experiments in Canada, Poland, and China to test whether monochamol was attractive to additional Monochamusspecies and if attraction was synergised by plant volatiles and bark beetle (Coleoptera: Curculionidae) pheromones. We provide the first evidence of attraction for M. urussovii(Fischer) and M. saltuarius(Gebler) to monochamol or monochamol+kairomones. The highest numbers of M. urussoviiwere captured in traps baited with monochamol+plant volatiles (Manuka oil, ethanol and (95/5±) a-pinene). Captures of M. saltuariuswere highest in traps baited with monochamol, with the addition of cubeb oil tending to reduce captures. The highest numbers of M. scutellatus(Say) were captured in traps baited with monochamol+kairomones. A similar pattern in trap captures was found for M. notatus(Drury), M. marmoratorKirby, M. carolinensis(Olivier), and M. mutatorLeConte. Detection rates, that is, proportion of traps capturing at least one specimen, was highest for traps baited with monochamol plus kairomones, particularly for less-common species. These results support the emerging hypothesis that pheromone compounds can attract related cerambycid species with cumulative evidence for attraction to monochamol for 12 species of Monochamusworldwide.

AbstractFirst detected in North America in 2002, the emerald ash borer (EAB) (Agrilus planipennisFairmaire; Coleoptera: Buprestidae), an invasive phloem-feeding beetle from Asia, has killed tens of millions of ash (FraxinusLinnaeus; Oleaceae) trees. Although few parasitoids attack EAB in North America, three parasitoid species were found attacking EAB in China: the egg parasitoid Oobius agriliZhang and Huang (Hymenoptera: Encyrtidae) and two larval parasitoids Tetrastichus planipennisiYang (Hymenoptera: Eulophidae) and Spathius agriliYang (Hymenoptera: Braconidae). In 2007, classical biological control of EAB began in the United States of America after release of these three species was approved. In 2013, release of the larval parasitoids was approved in Canada. Research continues at study sites in Michigan, United States of America where the establishment, prevalence, and spread of O. agriliand T. planipennisihave been monitored since 2008. However, establishment of S. agriliremains unconfirmed in northern areas, and its release is now restricted to regions below the 40th parallel. In 2015, approval for release of Spathius galinaeBelokobylskij (Hymenoptera: Braconidae), an EAB larval parasitoid from the Russian Far East, may be granted in the United States of America. Researchers are guardedly optimistic that a complex of introduced and native natural enemies will regulate EAB densities below a tolerance threshold for survival of ash species or genotypes in forested ecosystems.

AbstractAs of summer 2014, the invasive emerald ash borer (EAB), Agrilus planipennisFairmaire (Coleoptera: Buprestidae), has become established in 24 states in the United States of America and has killed tens of millions of ash trees since its introduction into Michigan in the 1990s. Considerable research has been conducted on many aspects of EAB life history, natural history, ecology, and management strategies in an attempt to contain this devastating pest. In this article, we review the life history, mating behaviours, and host plant selection by EAB in North America as well as host resistance to EAB attack.

AbstractEmerald ash borer (EAB), Agrilus planipennisFairmaire (Coleoptera: Buprestidae), is a non-native, wood-boring beetle that has caused widespread mortality of ash (FraxinusLinnaeus (Oleaceae)) in eastern North America. During 2004–2007, we determined whether forest community composition and structure of black (F. nigraMarshall), green (F. pennsylvanicaMarshall), and white (F. americanaLinnaeus) 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 QuercusLinnaeus (Fagaceae), AcerLinnaeus (Sapindaceae), and TiliaLinnaeus (Malvaceae); such vegetation changes will irreversibly alter the structure and function of these forests.

AbstractEmerald ash borer, Agrilus planipennisFairmaire (Coleoptera: Buprestidae), is an Asian species that was introduced into North America in the mid-1990s. The beetle has the potential to devastate populations of FraxinusLinnaeus (Oleaceae) species. Several species of Hymenoptera parasitoids have made the transition from North American AgrilusCurtis hosts to A. planipennis, and some (e.g., AtanycolusFörster (Hymenoptera: Braconidae) species) have caused substantial mortality. Invertebrate predators of A. planipennishave been poorly investigated. Predation by woodpeckers (Aves: Picidae) has had the greatest impact on A. planipennispopulations. Native entomopathogens have also been observed in populations of A. planipennisand are being explored as potential biological control agents. Agrilus planipennisis a freeze-intolerant species and as such perishes when its tissues freeze. However, the beetle can achieve a mean supercooling point of -30 °C by the production of cryoprotectants, especially glycerol. This low supercooling point in combination with temperatures higher than ambient in its overwintering microhabitat means that it can survive in most of its invaded range. As its distribution expands northward its cold hardiness may be challenged. North American species of Fraxinuspossess some resistance to A. planipennisvia defensive mechanisms, but these are quickly overcome by expanding larval populations. Intraspecific competition (via cannibalism and starvation) impacts larval survival.

AbstractPractical and effective strategies to manage emerald ash borer (EAB) (Agrilus planipennisFairmaire; Coleoptera: Buprestidae) are increasingly important given economic and ecological impacts of this invader. While EAB detection remains challenging, tactics are available to protect individual ash (FraxinusLinnaeus; Oleaceae) trees and slow EAB population growth, thereby delaying ash mortality. Simulations with a coupled map lattice model, parameterised with data from numerous field studies, showed treating trees with a highly effective systemic insecticide (TREE-äge™; emamectin benzoate), would be more effective in slowing EAB population growth than girdling trees to attract ovipositing females then destroying trees before larvae develop, while harvesting ash to reduce available phloem would have the least effect. From 2008 to 2012, cooperators participated in a pilot project to implement an integrated strategy for an EAB infestation in Upper Michigan, United States of America. Ash was inventoried and EAB density monitored using girdled ash detection trees supplemented with baited artificial traps across the >750 km2project area. While only a tiny fraction of ash trees in the project area were girdled (444–855 trees annually) or injected with TREE-äge™ (<360 roadside trees annually), and treatment distribution was restricted, both treatments slowed EAB population growth. Coupling TREE-äge™ injections with other tactics will likely yield additive or synergistic outcomes.

AbstractThe emerald ash borer (EAB), Agrilus planipennisFairmaire (Coleoptera: Buprestidae), is a destructive invasive pest that threatens North American ash (Fraxinus(Oleaceae)) and inflicts substantial aesthetic, ecological, and economic damage in urban forests and rural woodlands. Understanding adult EAB dispersal and spread of infestations is critical to effectively manage and mitigate its potential impact in North America and elsewhere. Challenges of quantifying short-distance and long-distance movement of adult EAB in the field remain exceptionally difficult. Here we review our current understanding of EAB spread. Research to date suggests natural spread of EAB populations is variable and influenced by local environmental conditions, but limited to only a few km per year. In contrast, long-distance spread resulting from anthropogenic movement of infested ash material, such as nursery trees or firewood, can greatly increase local and regional rate of spread through the formation of satellite populations. Key areas in need of future research are highlighted.