Biotic mortality factors affecting emerald ash borer (Agrilus planipennis) are highly dependent on life stage and host tree crown condition

2015 ◽  
Vol 105 (5) ◽  
pp. 598-606 ◽  
Author(s):  
D.E. Jennings ◽  
J.J. Duan ◽  
P.M. Shrewsbury

AbstractEmerald ash borer (EAB), Agrilus planipennis, is a serious invasive forest pest in North America responsible for killing tens to hundreds of millions of ash trees since it was accidentally introduced in the 1990s. Although host-plant resistance and natural enemies are known to be important sources of mortality for EAB in Asia, less is known about the importance of different sources of mortality at recently colonized sites in the invaded range of EAB, and how these relate to host tree crown condition. To further our understanding of EAB population dynamics, we used a large-scale field experiment and life-table analyses to quantify the fates of EAB larvae and the relative importance of different biotic mortality factors at 12 recently colonized sites in Maryland. We found that the fates of larvae were highly dependent on EAB life stage and host tree crown condition. In relatively healthy trees (i.e., with a low EAB infestation) and for early instars, host tree resistance was the most important mortality factor. Conversely, in more unhealthy trees (i.e., with a moderate to high EAB infestation) and for later instars, parasitism and predation were the major sources of mortality. Life-table analyses also indicated how the lack of sufficient levels of host tree resistance and natural enemies contribute to rapid population growth of EAB at recently colonized sites. Our findings provide further evidence of the mechanisms by which EAB has been able to successfully establish and spread in North America.

2015 ◽  
Vol 148 (3) ◽  
pp. 329-342 ◽  
Author(s):  
Xiao-Yi Wang ◽  
Liang-Ming Cao ◽  
Zhong-Qi Yang ◽  
Jian J. Duan ◽  
Juli R. Gould ◽  
...  

AbstractTo investigate natural enemies of emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), in northeastern China, we conducted field surveys of ash (Fraxinus Linnaeus (Oleaceae)) trees in semi-natural forests and plantations at variable EAB densities from 2008 to 2013. Our surveys revealed a complex of natural enemies including eight hymenopteran parasitoids and two apparently parasitic Coleoptera, woodpeckers, and several undetermined mortality factors. Parasitoid complex abundance and its contribution to EAB mortality varied with the time of year, type of ash stands, and geographic regions. The egg parasitoid Oobius agrili Zhang and Huang (Hymenoptera: Encyrtidae) and the larval parasitoid Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae) were frequently observed in Jilin, Liaoning, and Heilongjiang provinces and in Beijing, but not in Tianjin. Spathius agrili Yang (Hymenoptera: Braconidae), however, was more prevalent near Beijing and further south in Tianjin. Larvae of two species of apparently parasitic beetle, Tenerus Laporte (Coleoptera: Cleridae) species and Xenoglena quadrisignata Mannerheim (Coleoptera: Trogossitidae), were also recovered attacking overwintering EAB in Liaoning Province, with Tenerus species being a dominant mortality agent (~13%). Our findings support the need to consider the geographic origin of insect natural enemies for EAB biocontrol, as well as an expanded foreign exploration for EAB natural enemies throughout its native range in Asia.


2014 ◽  
Vol 147 (3) ◽  
pp. 263-276 ◽  
Author(s):  
D. Barry Lyons

AbstractEmerald ash borer, Agrilus planipennis Fairmaire (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 Fraxinus Linnaeus (Oleaceae) species. Several species of Hymenoptera parasitoids have made the transition from North American Agrilus Curtis hosts to A. planipennis, and some (e.g., Atanycolus Förster (Hymenoptera: Braconidae) species) have caused substantial mortality. Invertebrate predators of A. planipennis have been poorly investigated. Predation by woodpeckers (Aves: Picidae) has had the greatest impact on A. planipennis populations. Native entomopathogens have also been observed in populations of A. planipennis and are being explored as potential biological control agents. Agrilus planipennis is 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 Fraxinus possess some resistance to A. planipennis via defensive mechanisms, but these are quickly overcome by expanding larval populations. Intraspecific competition (via cannibalism and starvation) impacts larval survival.


Author(s):  
Deborah G McCullough

Abstract Emerald ash borer (EAB) (Agrilus planipennis Fairmaire), discovered in southeastern Michigan, USA in 2002, has become the most destructive and costly invasive forest insect in North America. This phloem-boring beetle has also invaded Moscow, Russia and continued spread of EAB potentially threatens European ash (Fraxinus spp.) species. This review summarizes EAB life history, including interspecific variation in host preference, invasion impacts and challenges of detecting new infestations and provides an overview of available management tactics. Advances in systemic insecticides, particularly emamectin benzoate products applied via trunk injection, have yielded effective and practical options both to protect individual trees and to slow EAB population growth and ash decline on an area-wide basis without disrupting natural enemies. Economic costs of treating ash are substantially lower than removal costs, retain ecosystem services provided by the trees, reduce sociocultural impacts and conserve genetic diversity in areas invaded by EAB. Girdled ash trees are highly attractive to EAB adults in low-density populations and debarking small girdled trees to locate larval galleries is the most effective EAB detection method. An array of woodpeckers, native larval parasitoids and introduced parasitoids attack EAB life stages but mortality is highly variable. Area-wide management strategies that integrate insecticide-treated trees, girdled ash trap trees and biological control can be adapted for local conditions to slow and reduce EAB impacts.


2015 ◽  
Vol 148 (3) ◽  
pp. 361-370 ◽  
Author(s):  
Jean J. Turgeon ◽  
Jeffrey G. Fidgen ◽  
Krista L. Ryall ◽  
Taylor A. Scarr

AbstractAgrilus planipennis (Coleoptera: Buprestidae), is causing extensive mortality of ash (Fraxinus Linnaeus; 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. planipennis feeding 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. planipennis gallery density/m2 of 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.


2013 ◽  
Vol 146 (1) ◽  
pp. 90-105 ◽  
Author(s):  
Philip Careless ◽  
Stephen A. Marshall ◽  
Bruce D. Gill

AbstractThe beetle-hunting wasp, Cerceris fumipennis Say (Hymenoptera: Crabronidae), native to eastern North America, provisions its subterranean nest almost exclusively with adult metallic wood-boring beetles (Coleoptera: Buprestidae), including the destructive emerald ash borer (Agrilus planipennis Fairmaire, EAB). This wasp provides a unique opportunity to survey indigenous and nonindigenous buprestid diversity. We discuss the accessibility, sustainability, and productivity of C. fumipennis with respect to its application as a buprestid surveying and monitoring tool.


2006 ◽  
Vol 12 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Jim R. Muirhead ◽  
Brian Leung ◽  
Colin Overdijk ◽  
David W. Kelly ◽  
Kanavillil Nandakumar ◽  
...  

2020 ◽  
Vol 93 (2) ◽  
pp. 187-196 ◽  
Author(s):  
H F Evans ◽  
D Williams ◽  
G Hoch ◽  
A Loomans ◽  
M Marzano

Abstract The threats posed by the buprestid beetles emerald ash borer (Agrilus planipennis Fairmaire) and bronze birch borer (Agrilus anxius Gory) have been the subject of considerable research, primarily to develop methods for detection and management of the pests. PREPSYS, a Euphresco project, has worked with collaborators globally to assess the ‘state of the art’ for the two insect pests and to identify those measures that would best prepare Europe for potential invasion by the pests, especially emerald ash borer which is now in the western part of Russia and in eastern Ukraine. Building on an excellent exchange of knowledge and discussion at the OECD-sponsored international conference held in Vienna in October 2018, the concept of a European Toolbox to increase preparedness for dealing with the pests has been developed. This includes key components including surveillance, direct intervention, use of natural enemies and increased awareness of the problems associated with the pests. Collaboration is essential in delivering and refining the European Toolbox.


2019 ◽  
Vol 113 (2) ◽  
pp. 622-632 ◽  
Author(s):  
Michael I Jones ◽  
Juli R Gould ◽  
Hope J Mahon ◽  
Melissa K Fierke

Abstract Biological control offers a long-term and sustainable option for controlling the destructive forest pest emerald ash borer (EAB), Agrilus planipennis Fairmaire, in North America. Three larval parasitoids, Spathius agrili Yang (Hymenoptera: Braconidae), Tetrastichus planipennisi Yang (Eulophidae), and Spathius galinae Belokobylskij & Strazanac, have been introduced to North America from the native range of EAB (northeastern Asia). While T. planipennisi appears to be persisting where it has been introduced in northern United States, S. agrili failed to establish in northeastern states. The more recently identified parasitoid S. galinae was recovered from the Russian Far East and climate matching suggests it should be suited for release in colder climates. We collected data on the phenology of EAB and its introduced larval parasitoids from colonies established in an insectary, growth chambers, and field-caged trees in Syracuse, New York to determine whether asynchrony between parasitoids and EAB or climate could impact establishment and persistence. Phenological data indicated EAB has one and 2-yr life cycles in New York, with parasitoid-susceptible EAB larvae available spring to fall for parasitism. Insectary and growth chamber studies indicated S. galinae and T. planipennisi were synchronous with EAB phenology, and field studies suggested both species could overwinter in northeastern climates. Spathius agrili was asynchronous with EAB phenology and climate, emerging when fewer parasitoid-susceptible EAB larvae were available and temperatures were not optimal for survival. Our results suggest S. galinae and T. planipennisi are suited for biological control of EAB at the northern limits of its range in North America.


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