Emerald Ash Borer Agrilus Planipennis Research Articles

Trade‐offs in parasitism efficiency and brood size mediate parasitoid coexistence, with implications for biological control of the invasive emerald ash borer

Summary Parasitoids often are selected for use as biological control agents because of their high host specificity, yet such host specificity can result in strong interspecific competition. Few studies have examined whether and how various extrinsic factors (such as parasitism efficiency, i.e. the ability to optimize host‐finding attack rates) influence the outcome of competition between parasitoids, even though they could have profound effects on the implementation of classical biological control programmes. To determine the potential influence of extrinsic competition and coexistence on host suppression efficacy, we compared parasitism by two larval parasitoids (Tetrastichus planipennisi and Spathius galinae) of the invasive emerald ash borer (EAB) Agrilus planipennis, under different host densities, parasitoid densities, host plant sizes and parasitoid–host ratios. Spathius galinae had significantly higher parasitism efficiency (≈4 times), but significantly lower brood size (>6 times) than that of T. planipennisi. The attack rates of hosts increased significantly with parasitoid density, whereas host density did not significantly affect multiparasitism. The parasitism rate of T. planipennisi on small host logs was significantly higher than that on large logs, while host plant (log) size had no significant impact on S. galinae parasitism. The multiparasitism rate was rather low regardless of host log size and parasitoid/host density, indicating that intrinsic competition between the two species of parasitoids might seldom occur in the field. The two species of parasitoids could therefore coexist in the same habitat, and any adverse effects on the suppression of EAB populations caused by competitive behaviour between the two species of parasitoids would likely be negligible. Synthesis and applications. Our findings suggest that introducing multiple species of parasitic natural enemies could be feasible for management of invasive species, but it is important to examine multiple extrinsic factors simultaneously when evaluating interspecific competition between them. Among these different extrinsic factors, we found that coexistence between parasitoids can be mediated by trade‐offs in their parasitism efficiency and brood sizes. Thus, the differences in life‐history traits of natural enemies could be used to select among biological control agents being considered for releases.

The influence of temperature on the flight capacity of emerald ash borer Agrilus planipennis and its parasitoid, Tetrastichus planipennisi: implications to biological control

The success of classical biological control programs often hinges on an appropriate climatic match between a novel ecosystem and an imported natural enemy. In particular, temperature is the most important factor mediating survival, developmental synchrony, and dispersal of invasive pests and their natural enemies. We used computer-monitored flight mills to investigate the roles of temperature and humidity in the flight distance, flight speed, number of flights, and post-flight mortality of emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) and its parasitoid Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) in laboratory settings. Flight distance had a concave, parabolic relationship with temperature for both insects. Maximum flight distances in 24 h occurred at 27.9 °C (1.13 km) for emerald ash borer and 26.5 °C (1.81 km) for T. planipennisi. Flight speed and post-flight mortality increased with temperature for both insects. Relative humidity was inversely related to flight speeds for emerald ash borer, but positively correlated with the number of flights and post-flight survival by T. planipennisi. We integrated the relationship between flight distance and temperature for both insects with landscape temperatures and flight periods for insects at ten locations across the continental USA to develop a flight index. The flight index offers a relative scale of flight capacity across locations based solely on temperature. We found that the flight index for Detroit was intermediate to low compared to other locations, with the smallest and largest flight indices projected in Minneapolis and Seattle for emerald ash borer and Seattle and Atlanta for T. planipennisi. The implications of results for host–parasitoid dispersal patterns and release protocols for distributing T. planipennisi are discussed.

Factors affecting the flight capacity of Tetrastichus planipennisi (Hymenoptera: Eulophidae), a classical biological control agent of Agrilus planipennis (Coleoptera: Buprestidae).

The dispersal characteristics of a biological control agent can have direct implications on the ability of that agent to control populations of a target host. Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) is a parasitic wasp native to eastern Asia that has been introduced into the United States as part of a classical biological control program against the emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). We used computer-monitored flight mills to investigate the role of age, feeding status, mating status, and size on the flight capacity of female T. planipennisi over a 24-h period. We also compared flight capacity between sexes. Flight distance of female T. planipennisi representative of populations released in the biological control program averaged 1.26 km in 24 h with a maximum flight of just over 7 km. Median flight distance, however, was 422 m. The flight capacity of females fed a honey-water solution was 41× that of females provided only water, who flew very little. Larger females were capable of flying farther distances, but age did not affect the flight capacity of females up to 70 d posteclosion. Females dispersed 6× farther than did their smaller, male counterparts. The implications of our findings to host-parasitoid interactions and release protocols for distributing T. planipennisi are discussed.

Natural enemies implicated in the regulation of an invasive pest: a life table analysis of the population dynamics of the emerald ash borer

The emerald ash borer Agrilus planipennis Fairmaire is a serious invasive forest pest of ash (Fraxinus) trees in North America. Life tables were constructed for both experimentally established cohorts and wild populations of planipennis on healthy host trees from 2008 to 2011 in six forests in central Michigan. 2 Life table analysis showed that the net population growth rates ( R0) for the experi- mental cohorts (16.0± 2.9) and associated wildA. planipennis (19.4 ± 1.9) were the highest for the first study period (2008-2009) at three Ingham Co. sites but decreased to 4.7 ± 0.9 and 4.6± 0.4, respectively, for the second (2009-2010) study period at the same sites. By contrast,R0 values of both experimental cohorts (5.7 ± 2.2) and associated wildA. planipennis populations (11.3± 2.5) were intermediate in the third (2010-2011) study period at different sites in the Gratiot and Shiawassee Cos. 3 The sudden decrease inR0 of both experimental and wildA. planipennis cohorts in the Ingham Co. sites corresponded with increases in parasitism by hymenopteran parasitoidsAtanycolus spp. (native) andTetrastichus planipennisi Yang (introduced), as well as an increase in woodpecker predation, indicating the role of these natural enemies in regulation of the pest's population dynamics.

Submersion as a tactic to prevent emergence of emerald ash borer Agrilus planipennis from black ash logs

Abstract Black ash (Fraxinus nigra Marshall) trees are an important cultural resource and provide the wood used for traditional contemporary basketry by numerous Native American and First Nation tribes in the U.S.A. and Canada. The invasion and subsequent spread of emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) threatens the ash resource in North America and the basketry tradition. Submersion of infested ash logs has been proposed as a potential tactic to control A. planipennis emergence, although the duration of submergence required to prevent adult beetle emergence is unknown. We assessed the survivorship of A. planipennis prepupae through adult beetle emergence in green ash (F. pennsylvanica Marshall) bolts submerged at weekly intervals for up to 6 weeks and in black ash bolts submerged at 4‐week intervals for up to 24 weeks. The moisture content of sapwood at depths where prepupal chambers are commonly found was quantified in the black ash bolts after 0, 12 and 24 weeks of submergence. Mortality of A. planipennis from prepupa to adult was low (5.7 ± 2.3%) for the first 6 weeks of submersion but rapidly increased to 100% in green ash and black ash bolts submerged for 8 weeks or longer. In black ash, the outer 1.3 cm of wood became highly saturated after submersion for 12 weeks (81.0 ± 4.5%) and moisture increased only slightly after 24 weeks (83.9 ± 2.8%). The results obtained in the present study indicate that A. planipennis prepupae in green ash and black ash bolts can survive complete submersion for extended periods of time (i.e. at least 6 weeks) and successfully emerge as adults afterwards. Logs submerged for at least 8 weeks, however, produced no live A. planipennis beetles, indicating that submersion represents an efficacious control option.

European range of the emerald ash borer Agrilus planipennis (Coleoptera: Buprestidae) is expanding: The pest destroys ashes in the northwest of Moscow oblast and in part of Tver oblast

Emerald ash borer Agrilus planipennis is a serious pest of ash. It was accidentally introduced to Moscow in the 1990s. In May 2013, ashes in four cities located to the northwest of Moscow were examined. In Zelenograd (20 km from Moscow), Klin (70 km from Moscow), and Konakovo (100 km from Moscow), most of the ashes have been already killed or severely damaged by the pest. Obviously, within the next several years, ashes will be entirely eliminated from green plantations of these cities. Ashes examined in Tver (145 km from Moscow) are not damaged. The European range of the pest has significantly expanded to the northwest. Its border now crosses Tver oblast.

Unexpected connections between residential urban forest diversity and vulnerability to two invasive beetles

Invasive pests pose a threat to the key environmental and social benefits provided by urban forests, and diverse tree planting is a primary management strategy for reducing pest vulnerability. For example, past urban forest losses to Dutch elm disease (DED) prompted municipal foresters to emphasize diversification, but it is unclear whether residential properties developed after the peak DED outbreak are actually more diverse than older properties. To address this issue, we inventoried all public and private trees on 150 residential properties in the Twin Cities Metropolitan Area, Minnesota, USA, and compared genus diversity on pre- and post-Dutch elm properties. We then quantified vulnerability to two current invasive pest threats, emerald ash borer (EAB) (Agrilus planipennis) and Asian longhorned beetle (ALB) (Anoplophora glabripennis), to evaluate whether higher diversity corresponds with lower pest vulnerability. We assessed vulnerability based on two fundamental urban forest metrics–frequency and size of vulnerable trees. Surprisingly, properties developed after the peak DED outbreak were less diverse than older properties. At the same time, less diverse post-Dutch elm properties exhibited low ALB vulnerability and modest EAB vulnerability, while more diverse older sites were highly susceptible to ALB. The importance of pest host specificity in characterizing urban forest vulnerability was underscored by low EAB vulnerability and high ALB vulnerability on our oldest study sites. This research highlights an apparent disconnect between the theoretical notion that higher diversity should reduce invasive pest vulnerability, and our empirical data indicating that genus diversity does not necessarily correspond with pest vulnerability.

Distribution, impact and rate of spread of emerald ash borer Agrilus planipennis (Coleoptera: Buprestidae) in the Moscow region of Russia

Surveys of ash trees along the major motorway routes leading away from the city of Moscow during July 2013 indicated that emerald ash borer (Agrilus planipennis) was well established up to 235 km west of the city and 220 km to the south. Over the last 4 years, the beetle has spread in these directions at an average rate of 30–41 km year, which cannot be explained by natural dispersal alone and implies that human-assisted transport is contributing significantly to the spread of the pest, probably via the hitchhiking of adult beetles on vehicles. The European common ash (Fraxinus excelsior) is uncommon in Moscow and in the boreal forests to the west and north, but those trees that are present suggest that this species is not killed as rapidly by A. planipennis as North American ash species and that it may need to suffer a degree of stress before it succumbs rapidly to infestation. Nevertheless, A. planipennis is a major threat to F. excelsior, and south of Moscow, where the beetle has become established in natural broadleaved woodlands in which F. excelsior is a major component, many of the ash trees are suffering severe dieback and mortality. The abundance and almost continuous distribution of F. excelsior in these woodlands means that A. planipennis now has the opportunity to spread unhindered on a broad front to other countries in Europe.

First detection of Agrilus planipennis in Connecticut made by monitoring Cerceris fumipennis (Crabronidae) colonies

Smoky winged beetle bandits, Cerceris fumipennis Say, digger wasps in the family Hymenoptera: Crabronidae: Cercerini, provision their underground nests with adult metallic wood-boring beetles (Coleoptera: Buprestidae). Researchers, as well as engaged community volunteers, in several states have monitored female wasps returning to their nests as a means to detect invasive buprestid species. In this paper, we report the first detection of emerald ash borer (Agrilus planipennis Fairemore), an invasive beetle responsible for killing millions of ash trees in North America, in Connecticut by C. fumipennis and discuss its relationship to A. planipennis survey efforts by other modalities in the state. We also report detections of A. planipennis by C. fumipennis in Illinois, New York and Ontario; all of which were made after it was known the beetle was in the area. These findings support the use of C. fumipennis as a biomonitoring tool and bolster the use of engaged volunteers.

Effects of the emerald ash borer invasion on four species of birds

The emerald ash borer (EAB) Agrilus planipennis, first detected in 2002 in the vicinity of Detroit, Michigan, USA, is one of the most recent in a long list of introduced insect pests that have caused serious damage to North American forest trees, in this case ash trees in the genus Fraxinus. We used data from Project FeederWatch, a citizen science program focused on winter bird populations, to quantify the effects of EAB invasion on four species of resident, insectivorous birds known or likely to be EAB predators: three woodpecker species and the white- breasted nuthatch (Sitta canadensis). We compared relative numbers of birds within 50 km of the epicenter of the region where EAB was first detected, an area known to have suffered high ash tree mortality by 2008, to numbers 50-100 km from the epicenter and to control sites within 50 km of five comparable Mid- western cities where damage due to EAB has yet to be severe. We found evidence for significant effects on all four of the species in response to the EAB invasion in the highly impacted region, with red-bellied wood- peckers (Melanerpes carolinus) and white-breasted nuthatches showing numerical increases while downy woodpeckers (Picoides pubescens) and hairy wood- peckers (Picoides villosus) initially declined but exhibited at least temporary increases several years later. Temporal correlation analyses failed to provide support for immigration being a major cause of the elevated numbers in the highly impacted area, and thus these results are consistent with the hypothesis that increases were due to enhanced survival and/or repro- duction associated with the EAB invasion within the highly impacted area. Results suggest that the contin- uing invasion of EAB into new areas is likely to significantly alter avian communities, although not always in ways that will be easy to predict.

Buprestidae Collected as Prey by the Solitary, Ground-Nesting Philanthine Wasp Cerceris fumipennis (Hymenoptera: Crabronidae) in North Carolina

ABSTBACT The solitary, ground-nesting crabronid wasp Cerceris fumipennis Say excels at detecting buprestid diversity in a given geographic area, and after the introduction of the invasive pest emerald ash borer (Agrilus planipennis Fairmaire) to the United States in 2002, has been developed as an effective tool for the biosurveillance of pest Buprestidae in eastern North America. Here we report records of Buprestidae collected from foraging C. fumipennis in 13 North Carolina counties over the course of three seasons (2009–2011). Nests of the wasp were located, and beetle prey collected from foraging females in three geographic regions, with a concentration on the western, mountainous area of the state. In total, 909 beetles were collected, comprising 52 buprestid species that included eight native pests and 17 species of Agrilus. Our results emphasize the utility of C. fumipennis in documenting buprestid biodiversity and in detecting forest pests. Eight new state records and five new prey records for the wasp are here recorded.

Differential utilization of ash phloem by emerald ash borer larvae: ash species and larval stage effects

Two experiments were performed to determine the extent to which ash species (black, green and white) and larval developmental stage (second, third and fourth instar) affect the efficiency of phloem amino acid utilization by emerald ash borer (EAB) Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) larvae. EAB larvae generally utilized green ash amino acids more efficiently than those of the other two species. For example, the concentrations of only six (two essential) and seven (two essential) amino acids were lower in frass from EAB that fed upon black and white ash than in the corresponding phloem, respectively. By contrast, concentrations of 16 (eight essential) amino acids were lower in the frass from EAB that fed upon green ash than in the phloem. In addition, in green ash, the frass : phloem ratios of 13 amino acids were lower than their counterparts in black and white ash. The concentrations of non‐essential amino acids glycine and hydroxylproline were greater in frass than in phloem when EAB fed on black ash, although not when EAB fed on green or white ash. The concentration of total phenolics (a group of putative defensive compounds to EAB, expressed as antioxidant activity of acetone extraction) was high in EAB frass but even higher in the phloem samples when the data were pooled across ash species and EAB larval stages. This suggests EAB larvae may eliminate phenolics through a combination of direct excretion and enzymatic conversion of phenolics to nonphenolics before excretion. Because the ratio of frass total phenolics to phloem total phenolics in white ash was lower than the ratios in black and green ash, the ability to destroy phenolics or convert them to nonphenolics was greater when EAB larvae fed on white ash. Fourth‐instar EAB extracted phloem amino acids, including threonine, more efficiently than third‐instar EAB. The different larval developmental stages of EAB did not differ in their apparent ability to destroy phenolics or convert them to nonphenolics.

Wing wear is a poor estimate of age in Cerceris fumipennis (Hymenoptera, Crabronidae)

The native, ground nesting, beetle hunting philanthine wasp Cerceris fumipennis Say is in development as a biosurveillance tool to detect Emerald Ash Borer (Agrilus planipennis) and other pest Buprestidae threatening the forests of North America (Marshall et al. 2005; Careless and Marshall 2010; Nalepa and Swink 2011). As part of that effort the North Carolina (NC) Department of Agriculture & Consumer Services has been working to determine the phenology and life history of C. fumipennis in the state, primarily to determine its activity overlap with prey species of interest. An examination of specimens in the NC State University Insect Museum indicated that C. fumipennis had been collected in Wake County, NC, as early as 24 May and as late as 22 September between 1921 and 1982, and Kurczewski and Miller (1984) noted that C. fumipennis probably has a partial second brood in the south. Observations of wing wear of C. fumipennis females in Wake County during 2009 suggested that there may be either an extended emergence of a single generation, or that more than one generation per year occurs in the state. During the third week of July, females with completely intact wings as well as females with severely damaged wing margins were both present in the same nesting aggregation. In 2010 a study was conducted at that aggregation, a baseball diamond in the Raleigh City Parks system, to determine if wing wear in C. fumipennis may be positively correlated with female age. Shortly after nests began appearing at the site (30 May), females were captured and given a unique mark on the thorax using DecoColor opaque paint markers (Fig. 1a). A picture of each marked female’s right wing was taken with a Sony Cybershot JHR 24: 43–46 (2012)

Population responses of hymenopteran parasitoids to the emerald ash borer (Coleoptera: Buprestidae) in recently invaded areas in north central United States

Populations of hymenopteran parasitoids associated with larval stages of the invasive emerald ash borer (EAB) Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) were surveyed in 2009 and 2010 in the recently invaded areas in north central United States (Michigan), where two introduced EAB larval parasitoids, Tetrastichus planipennisi Yang and Spathius agrili Yang were released for classical biological control. Results from two years of field surveys showed that several hymenopteran parasitoids have become associated with EAB in Michigan. Among these parasitoids, the gregarious species T. planipennisi was the most abundant, accounting for 93% of all parasitoid individuals collected in 2009 (immediately after field release) and 58% in 2010 (a year later after field releases). Low levels (1–5%) of parasitism of EAB larvae by T. planipennisi were consistently detected at survey sites in both years. Separately, the abundance of the native parasitoid, Atanycolus spp., increased sharply, resulting in an average parasitism rate of EAB larvae from <0.5% in 2009 to 19% in 2010. Other parasitoids such as Phasgonophora sulcata Westwood, Spathius spp., Balcha indica Mani & Kaul, Eupelmus sp., and Eurytomus sp. were much less abundant than T. planipennisi and Atanycolus spp., and each caused <1% parasitism. Besides hymenopteran parasitoids, woodpeckers consumed 32–42% of the immature EAB stages present at our study sites, while undetermined biotic factors (such as microbial disease and host tree resistance) caused 10–22% mortality of observed EAB larvae. Relevance of these findings to the potential for biological control of EAB in the invaded areas of North America is discussed.

A review of species of the genus Oobius Trjapitzin, 1963 (Hymenoptera, Encyrtidae)—Egg parasitoids of jewel beetles, longicorn beetles (Coleoptera, Buprestidae, Cerambycidae), and robber flies (Diptera, Asilidae)

The review contains diagnosis of the genus Oobius Trjapitzin, 1963 (Hymenoptera, Encyrtidae), a key to the females of its 9 species described in the world fauna, and synopsis of the species with data on their distribution and hosts. Special attention is paid to an economically important species, Oobius agrili Zhang et Wang, 2005, introduced from China into USA and Canada for biological control of the emerald ash borer Agrilus planipennis Fairmaire (Coleoptera, Buprestidae), a very dangerous pest of ashes (Fraxinus spp.). This buprestid has also recently penetrated into Russia, which necessitates introduction of its egg parasitoid, O. agrili. Coccidencyrtus pinicola Mercet, 1921 from Spain is transferred to the genus Oobius, hence a new combination, O. pinicola (Mercet), comb. n., is proposed. The lectotype of Tyndarichus rudnevi S. Nowicki, 1928 (type species of the genus Oobius) is designated in the collection of the National Museum of Natural Sciences in Madrid and this is formally fixated in the present review. The material of Oobius has been studied in depositories of St. Petersburg, Warsaw, Madrid, and Monterrey (Mexico).

High temperature tolerance and thermal plasticity in emerald ash borer Agrilus planipennis

The emerald ash borer Agrilus planipennis (Coleoptera: Buprestidae) (EAB), an invasive wood-boring beetle, has recently caused significant losses of native ash (Fraxinus spp.) trees in North America. Movement of wood products has facilitated EAB spread, and heat sanitation of wooden materials according to International Standards for Phytosanitary Measures No. 15 (ISPM 15) is used to prevent this. 2 In the present study, we assessed the thermal conditions experienced during a typical heat-treatment at a facility using protocols for pallet wood treatment under policy PI-07, as implemented in Canada. The basal high temperature tolerance of EAB larvae and pupae was determined, and the observed heating rates were used to investigate whether the heat shock response and expression of heat shock proteins occurred in fourth-instar larvae. 3 The temperature regime during heat treatment greatly exceeded the ISPM 15 requirements of 56 ◦ C for 30 min. Emerald ash borer larvae were highly tolerant of elevated temperatures, with some instars surviving exposure to 53 ◦ C without any heat pre-treatments. High temperature survival was increased by either slow warming or pre-exposure to elevated temperatures and a recovery regime that was accompanied by up-regulated hsp70 expression under some of these conditions. 4 Because EAB is highly heat tolerant and exhibits a fully functional heat shock response, we conclude that greater survival than measured in vitro is possible under industry treatment conditions (with the larvae still embedded in the wood). We propose that the phenotypic plasticity of EAB may lead to high temperature tolerance very close to conditions experienced in an ISPM 15 standard treatment.

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.

Effectiveness of Differing Trap Types for the Detection of Emerald Ash Borer (Coleoptera: Buprestidae)

The early detection of populations of a forest pest is important to begin initial control efforts, minimizing the risk of further spread and impact. Emerald ash borer (Agrilus planipennis Fairmaire) is an introduced pestiferous insect of ash (Fraxinus spp. L.) in North America. The effectiveness of trapping techniques, including girdled trap trees with sticky bands and purple prism traps, was tested in areas with low- and high-density populations of emerald ash borer. At both densities, large girdled trap trees (>30 cm diameter at breast height [dbh], 1.37 m in height) captured a higher rate of adult beetles per day than smaller trees. However, the odds of detecting emerald ash borer increased as the dbh of the tree increased by 1 cm for trap trees 15-25 cm dbh. Ash species used for the traps differed in the number of larvae per cubic centimeter of phloem. Emerald ash borer larvae were more likely to be detected below, compared with above, the crown base of the trap tree. While larval densities within a trap tree were related to the species of ash, adult capture rates were not. These results provide support for focusing state and regional detection programs on the detection of emerald ash borer adults. If bark peeling for larvae is incorporated into these programs, peeling efforts focused below the crown base may increase likelihood of identifying new infestations while reducing labor costs. Associating traps with larger trees ( approximately 25 cm dbh) may increase the odds of detecting low-density populations of emerald ash borer, possibly reducing the time between infestation establishment and implementing management strategies.

Antennally Active Macrolide from the Emerald Ash Borer Agrilus planipennis Emitted Predominantly by Females

The macrocyclic lactone (3Z)-dodecen-12-olide was identified from the emissions of the emerald ash borer, Agrilus planipennis, feeding on ash foliage. The compound was detected from both sexes but was ca. 10 times more abundant from females. It was readily sensed by antennae of both males and females. Identification was confirmed by synthesis. The behavioral effects of the lactone remain unstudied in A. planipennis, but a verified pheromonal function could lead to improved monitoring for this invasive pest. The lactone is part of the pheromone of Cryptolestes pusillus, an unrelated beetle species.

Patterns in the within‐tree distribution of the emerald ash borer Agrilus planipennis (Fairmaire) in young, green‐ash plantations of south‐western Ontario, Canada

Abstract1 The emerald ash borer Agrilus planipennis Fairmaire (Coleoptera: Buprestidae) is a serious exotic pest of ash trees (Fraxinus spp.) in North America, and is responsible for the deaths of millions of trees in Ontario and Michigan. One of the greatest challenges facing the successful management of the pest is the ability to accurately detect its presence in a tree.2 Observations were made on A. planipennis larval feeding galleries found within 65 young, green‐ash trees cut from plantations in Essex County, Ontario, Canada. The within‐tree distributions of feeding galleries were described in relation to height‐above‐ground, stem diameter, bark thickness and stem aspect.3 Galleries were not distributed randomly or evenly; minimum boundaries of stem diameter and bark thickness and a maximum boundary of height‐above‐ground were detected. Indications of maximum boundaries for stem diameter and bark thickness were also observed. Galleries were found most often on the south‐west side of the tree.4 Using the technique of upper boundary regression, we were able to identify significant quadratic relationships between A. planipennis gallery density and stem diameter and bark thickness, as well as a significant negative linear relationship between gallery density and height‐above‐ground.5 Agrilus planipennis gallery density in newly‐infested trees was lower than in previously‐infested trees, and was observed to peak at smaller stem diameters and bark thicknesses than in previously‐infested trees.6 Survey teams would increase their probability of detecting new A. planipennis infestations by initiating searches for exit holes and feeding galleries in trunk sections and branches of approximately 7 cm in diameter.