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S M Salom - One of the best experts on this subject based on the ideXlab platform.
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Assessment of the potential for hybridisation between Laricobius nigrinus (Coleoptera: Derodontidae) and Laricobius osakensis, predators of the Hemlock Woolly Adelgid (Hemiptera: Adelgidae)
Biocontrol Science and Technology, 2015Co-Authors: Melissa J. Fischer, S M Salom, Nathan P. Havill, Carlyle C. Brewster, Loke T. KokAbstract:In 2003, Laricobius nigrinus Fender was introduced into the eastern United States as a biological control agent of the Hemlock Woolly Adelgid (Adelges tsugae Annand). Following its release, it was discovered that L. nigrinus was hybridising and producing viable progeny with Laricobius rubidus LeConte, a species native to eastern North America. Recently, Laricobius osakensis Montgomery and Shiyake was imported from Japan into the USA as a potential biological control agent of Hemlock Woolly Adelgid. Hybridisation between L. nigrinus and L. rubidus led to interest in the outcome of interactions between L. osakensis and the other two Laricobius spp. The purpose of this study was to determine if L. osakensis could mate with L. nigrinus, if they could produce hybrid progeny, and whether mating interferes with reproductive output. Laricobius spp. were observed mating directly following emergence and found to be capable of producing sterile eggs in the absence of a mating event. Laboratory and confined field stu...
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Characterization of physical and chemical defenses in the Hemlock Woolly Adelgid.
Journal of Chemical Ecology, 2014Co-Authors: Anne C. Jones, Donald E. Mullins, Tappey H. Jones, S M SalomAbstract:The invasive Hemlock Woolly Adelgid (Adelges tsugae Annand, Hemiptera: Sternorrhyncha: Adelgidae) causes significant mortality to eastern and Carolina Hemlock (Tsuga canadensis Carriere and T. caroliniana Engelmann, respectively) throughout the eastern United States. Adelges tsugae produces vast quantities of a wax covering that surrounds most of the instars as well as the adult and eggs. Using direct probe EI mass spectrometry, this wax covering was characterized as a diketoester wax, 17-oxohexatriacontanyl 11-oxotriacontanoate, and accounted for ≈ 42 % of A. tsugae total biomass. The presence of the anthraquinone, chrysophanol, and its precursor anthrone, chrysarobin, in A. tsugae has only been briefly described. Further study confirmed these compounds in all A. tsugae life stages. Additionally, several predatory beetles in use or under consideration as biological control agents for this species appear to ingest and excrete these compounds when feeding on A. tsugae. The production of both a physical and a chemical defense may represent a significant energy investment by A. tsugae.
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Biology and Control of Hemlock Woolly Adelgid
2014Co-Authors: Nathan P. Havill, Ligia C. Vieira, S M SalomAbstract:This publication is a substantial revision of FHTET 2001-03, Hemlock Woolly Adelgid, which was published in 2001. This publication contains information on the native range of Hemlock and range of Hemlock Woolly Adelgid, the importance of Hemlocks in eastern forest ecosystems, and on hosts, life cycle, control, and population trends of the Hemlock Woolly Adelgid.
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Hemlock Woolly Adelgid: a threat to eastern forests
2014Co-Authors: Nathan P. Havill, Ligia C. Vieira, S M SalomAbstract:The Hemlock Woolly Adelgid (HWA) (Adelges tsugae Annand) is a destructive, non-native pest of forest and ornamental Hemlock trees in eastern North America. It was first collected in the eastern United States in 1951 in Richmond, Virginia, arriving sometime earlier directly from southern Japan, probably on live plant material. Other than its new association with eastern and Carolina Hemlock, HWA has been historically associated with Hemlock species in western North America and Asia. The geographic range of eastern Hemlock extends from the Canadian Maritime Provinces, west to the Great Lakes region, and as far south as northern Georgia and Alabama, with many separated populations to the south and west of its main range.
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Potential feeding deterrents found in Hemlock Woolly Adelgid, Adelges tsugae.
Naturwissenschaften, 2012Co-Authors: Anne C. Jones, Donald E. Mullins, Tappey H. Jones, S M SalomAbstract:The nonnative Hemlock Woolly Adelgid (Adelges tsugae Annand, Hemiptera: Sternorrhyncha: Adelgidae) has been a significant mortality agent of eastern Hemlock (Tsuga canadensis Carriere) throughout a large portion of its geographic range. During a study investigating Adelgid vigor in relation to host health, it was noted that Adelgid extracts ranged from a yellow to a deep red color. Analysis by GC–MS identified the presence of the anthraquinone, chrysophanol and its anthrone precursor, chrysarobin in the extract. These compounds are predator deterrents in several other insects, including chrysomelid beetles. It is hypothesized that these compounds serve a similar purpose in the Hemlock Woolly Adelgid.
Michael E. Montgomery - One of the best experts on this subject based on the ideXlab platform.
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Hemlock Woolly Adelgid and its Hemlock hosts: A global perspective
2011Co-Authors: Nathan P. Havill, Michael E. Montgomery, Melody A. KeenaAbstract:The Hemlock Woolly Adelgid (HWA), Adelges tsugae Annand (Hempitera: Adelgidae), threatens the health and sustainability of the native eastern North American Hemlocks, Tsuga canadensis (L.) Carriere and T. caroliniana Engelman. The lineage of HWA that was introduced to the eastern United States came from Japan sometime prior to 1951, and did not co-evolve with eastern North American forest ecosystems (Havill et al. 2006). As a result, eastern Hemlock species cannot adequately resist or tolerate the impacts of Adelgid feeding, and the native community of natural enemies in eastern North America is not capable of maintaining HWA populations below damaging levels. This results in widespread death of Hemlock trees, which is having serious consequences for biodiversity, ecosystem functions, and ornamental and urban resources.
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Research and development program on host plant resistance to Hemlock Woolly Adelgid
2009Co-Authors: Michael E. Montgomery, Kurt W. GottschalkAbstract:Adelges tsugae Annand, the Hemlock Woolly Adelgid (HWA), is a serious pest of Hemlocks in the eastern United States. Hemlocks native to western North America and Asia are not damaged by this sucking insect. Recent phylogenetic research (Havill et al. 2006) determined that HWA is native to western North America and Asia and that the population in the eastern U.S. is non-native and came from Japan. It is hypothesized that in the areas where HWA is native, a combination of host resistance and natural enemies maintains HWA populations below damaging levels.
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Hemlock Woolly Adelgid population genetics
2009Co-Authors: Nathan P. Havill, Melody A. Keena, Michael E. Montgomery, Ashley Lamb, Shigehiko Shiyake, Adalgisa CacconeAbstract:The Hemlock Woolly Adelgid, Adelges tsugae (Hemiptera: Adelgidae), was first reported in eastern North America over 50 years ago. Efforts to control the impacts of the Adelgids are focusing on classical biological control and tree resistance. The success of these strategies relies on knowledge of the ecological and evolutionary context uniting the pest, its host plants, and its natural enemies.
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Low temperature in the Hemlock Woolly Adelgid system
2008Co-Authors: Scott D. Costa, Michael E. Montgomery, Robert T. Trotter, Michael. FortneyAbstract:Hemlock Woolly Adelgid (HWA) vary in their susceptibility to temperatures considerably below freezing. Many individuals may die by -20°C (-4°F), but more cold-tolerant individuals will allow populations to persist. Managers wanting to gauge temperature impacts on future Adelgid pressure to Hemlock forests may benefit from using available daily records of minimum low temperatures. More robust data on Adelgid temperature response will enhance development of models/tools to assist in their forecasts. Exotic predators being released to suppress Adelgid populations (Sasajiscymnus tsugae, Scymnus sinuanodulus, Scymnus ningshanensis, and Laricobius nigrinus) may be slightly less cold-tolerant than the Adelgid, but the cold-tolerance does not appear to be affected by feeding. These predators are able to feed at near 0oC temperatures. In areas with relatively cold climates, the low winter temperature and the four predators tested could work together to regulate HWA populations.
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Recovery of Hemlock Woolly Adelgid predators in the high country of northwestern North Carolina, 2004-2008
2008Co-Authors: Richard Mcdonald, S M Salom, Michael E. Montgomery, D. L. Mausel, Loke Kok, Gina Luker, Stan Steury, Gene Spears, Stewart Skeate, James GrahamAbstract:Three species of predatory beetles have been released to combat infestations of the Hemlock Woolly Adelgid in the High Country region of northwestern North Carolina. They are the spring/summer predators Sasajiscymnus tsugae Sasaji (St), Scymnus sinuanodulus Yu and Yao (Ss), and the winter/fall predator Laricobius nigrinus Fender (Ln). A total of 890 adults of St have been released at three sites and adults were recovered from two of the three sites; one site was two years old. We also recovered St from a site where no releases were made by this group (Lees McRae Field Site).
Nathan P. Havill - One of the best experts on this subject based on the ideXlab platform.
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Spring bird migration as a dispersal mechanism for the Hemlock Woolly Adelgid
Biological Invasions, 2019Co-Authors: Nicholas J. Russo, Nathan P. Havill, Chris S. Elphick, Morgan W. TingleyAbstract:In eastern North America, the invasive Hemlock Woolly Adelgid (Adelges tsugae Annand), has expanded northward at a pace that exceeds predictions from mechanistic models, suggesting successful long-distance dispersal despite the only viable dispersive phase being a flightless nymph, or “crawler.” We hypothesize that migrating birds may contribute to long-distance dispersal of crawlers by passively transporting them in their plumage during northward migration. We collected Hemlock Woolly Adelgid crawlers from the plumage of wild birds in Connecticut Hemlock forests in spring and summer 2016–2017 and evaluated the factors that influence crawler loads on wild birds. Of 456 birds examined, 40 individuals of 22 species carried Adelgid crawlers. Crawler loads varied strongly over time, showing a mid-spring peak that mirrored the phenological pattern in crawler abundance. However, crawler load was not affected by either local crawler abundance at capture sites or the degree of bird species association with Hemlock forests. To test whether dispersed crawlers could start new invasions, we experimentally simulated avian-assisted dispersal of Adelgids onto uninfested nursery Hemlocks. Although rare, crawlers placed on birds did settle successfully on experimental branches during the Adelgid’s summer generation. Our study confirms that birds carry Hemlock Woolly Adelgid crawlers most often during the period of peak spring songbird migration, and that crawlers can move off bird plumage to settle on Hemlock foliage. Bird-mediated, long-distance dispersal of crawlers likely has played a key role in Hemlock Woolly Adelgid spread, and with warming temperatures, this mechanism may continue to be important for future range expansion.
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Cryptic east-west divergence and molecular diagnostics for two species of silver flies (Diptera: Chamaemyiidae: Leucopis ) from North America being evaluated for biological control of Hemlock Woolly Adelgid
Biological Control, 2018Co-Authors: Nathan P. Havill, Stephen D. Gaimari, Adalgisa CacconeAbstract:Abstract Exploring genetic diversity within species of biological control agents can expose previously overlooked beneficial genotypes. This may be the case for two species of silver flies, Leucopis argenticollis and L. piniperda, predators of the Hemlock Woolly Adelgid (Adelges tsugae) in the Pacific Northwest of North America. The same Leucopis species occur in eastern North America, where they feed on other Adelgid species, but not on Hemlock Woolly Adelgid, which became a pest in the region after its introduction from Japan earlier this century. We collected DNA sequence data from one mitochondrial and two nuclear genes for 606 Leucopis individuals to examine variation correlated with geographic origin and prey association. Specimens of L. argenticollis and L. piniperda collected from Adelgids on Hemlock and spruce in the West are phylogenetically divergent from conspecifics collected from Adelgids on pine and spruce in the East. These results suggest that within each species, there are distinct lineages that specialize on different Adelgid prey on different hosts in western versus eastern North America. The western lineages appear to be strong candidates for enhancing biological control of Japanese Hemlock Woolly Adelgid in the eastern United States, given their widespread occurrence on western Hemlock Woolly Adelgid in the Pacific Northwest, and the absence of these genotypes in the East. We also developed a PCR-RFLP assay based on the mitochondrial COI gene as an inexpensive and reliable way to distinguish the four genetic groups to document establishment and impact following release.
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Assessment of the potential for hybridisation between Laricobius nigrinus (Coleoptera: Derodontidae) and Laricobius osakensis, predators of the Hemlock Woolly Adelgid (Hemiptera: Adelgidae)
Biocontrol Science and Technology, 2015Co-Authors: Melissa J. Fischer, S M Salom, Nathan P. Havill, Carlyle C. Brewster, Loke T. KokAbstract:In 2003, Laricobius nigrinus Fender was introduced into the eastern United States as a biological control agent of the Hemlock Woolly Adelgid (Adelges tsugae Annand). Following its release, it was discovered that L. nigrinus was hybridising and producing viable progeny with Laricobius rubidus LeConte, a species native to eastern North America. Recently, Laricobius osakensis Montgomery and Shiyake was imported from Japan into the USA as a potential biological control agent of Hemlock Woolly Adelgid. Hybridisation between L. nigrinus and L. rubidus led to interest in the outcome of interactions between L. osakensis and the other two Laricobius spp. The purpose of this study was to determine if L. osakensis could mate with L. nigrinus, if they could produce hybrid progeny, and whether mating interferes with reproductive output. Laricobius spp. were observed mating directly following emergence and found to be capable of producing sterile eggs in the absence of a mating event. Laboratory and confined field stu...
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Biology and Control of Hemlock Woolly Adelgid
2014Co-Authors: Nathan P. Havill, Ligia C. Vieira, S M SalomAbstract:This publication is a substantial revision of FHTET 2001-03, Hemlock Woolly Adelgid, which was published in 2001. This publication contains information on the native range of Hemlock and range of Hemlock Woolly Adelgid, the importance of Hemlocks in eastern forest ecosystems, and on hosts, life cycle, control, and population trends of the Hemlock Woolly Adelgid.
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Hemlock Woolly Adelgid: a threat to eastern forests
2014Co-Authors: Nathan P. Havill, Ligia C. Vieira, S M SalomAbstract:The Hemlock Woolly Adelgid (HWA) (Adelges tsugae Annand) is a destructive, non-native pest of forest and ornamental Hemlock trees in eastern North America. It was first collected in the eastern United States in 1951 in Richmond, Virginia, arriving sometime earlier directly from southern Japan, probably on live plant material. Other than its new association with eastern and Carolina Hemlock, HWA has been historically associated with Hemlock species in western North America and Asia. The geographic range of eastern Hemlock extends from the Canadian Maritime Provinces, west to the Great Lakes region, and as far south as northern Georgia and Alabama, with many separated populations to the south and west of its main range.
Joseph S. Elkinton - One of the best experts on this subject based on the ideXlab platform.
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Density-Dependent Recruitment and Diapause in the Spring-Feeding Generation of Hemlock Woolly Adelgid (Hemiptera: Adelgidae) in Western North America.
Environmental Entomology, 2016Co-Authors: Aaron S. Weed, Joseph S. Elkinton, Nina K. LanyAbstract:Insect populations are affected by density-dependent and density-independent factors, and knowing how these factors affect long-term population growth is critical to pest management. In this study, we experimentally manipulated densities of the Hemlock Woolly Adelgid on eastern and western Hemlock trees in the western USA to evaluate the effects of density and host species on Hemlock Woolly Adelgid crawler colonization. We then followed development of Hemlock Woolly Adelgid on each Hemlock species. Settlement of crawlers was strongly density-dependent and consistent between host species. In addition, a period of hot days that coincided with the settlement of Hemlock Woolly Adelgid crawlers put our experimental and naturally occurring populations into diapause during April. Diapause resulted in one generation that yr in our experimental population. Analyses of long-term air temperature records indicated that diapause-inducing temperatures in April similar to those observed in our experiment have occurred rarely since 1909 and the frequency of these events has not changed over time. Prior work suggests that Hemlock Woolly Adelgid completes two generations per yr in the western USA with a diapause occurring in the summer. This typical life history reflects the long-term influence of regional average seasonal temperature patterns on development and the timing of diapause-inducing temperatures. However, the timing of unseasonal weather, such as the hot days observed in our experiment, occasionally changes life history trajectories from this normal pattern. Our results show that density-dependent and density-independent factors have strong effects on generational mortality and life history of Hemlock Woolly Adelgid that are important to its population dynamics and management.
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Survival and Near Extinction of Hemlock Woolly Adelgid (Hemiptera: Adelgidae) During Summer Aestivation in a Hemlock Plantation
Environmental Entomology, 2015Co-Authors: Elizabeth M. Sussky, Joseph S. ElkintonAbstract:Varying densities of the spring generation of the Hemlock Woolly Adelgid were manipulated on 16 previously uninfested eastern Hemlocks in an open-field plantation in Massachusetts. In contrast to experimentally created Hemlock Woolly Adelgid populations in a forest, as reported previously, there was no evidence of density-dependent survival on a tree-wide basis in the plantation in the spring (progrediens) generation. There was, however, comparable density-dependent survival of settled crawlers and sexupara production when samples of the population were examined from branches with high density. Plantation Hemlocks had 9.3 times more foliage and 10 times lower Adelgid densities per cm than the forest Hemlocks. These results show that density-dependent processes in the progrediens generation may only be evident when Hemlock Woolly Adelgid density reaches a critical threshold. In the sistens generation that begins in midsummer, we counted a mean of 126 settled crawlers on marked branch on all 16 trees, but none of these Adelgids survived the mid-summer aestivation phase, perhaps due to higher temperatures that were recorded in the plantation compared with a nearby Hemlock forest, where 16% of the Adelgids survived the aestivation phase. Whole tree counts of overwintering Adelgids revealed that the Adelgid populations had gone extinct on 13 out of the 16 trees. Mortality in the midsummer aestivation phase often exceeds overwintering mortality that has been widely thought to be the main factor that limits Adelgid population growth and spread, particularly in northern states.
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Hemlock Woolly Adelgid (Hemiptera: Adelgidae) Induces Twig Volatiles of Eastern Hemlock in a Forest Setting
Environmental Entomology, 2014Co-Authors: Joshua Pezet, Joseph S. ElkintonAbstract:The Hemlock Woolly Adelgid (Adelges tsugae Annand) is an invasive species causing high mortality of eastern Hemlock (Tsuga canadensis (L) Carriere) in the forests of eastern North America. Recent findings revealed that sapling eastern Hemlocks artificially infested with Hemlock Woolly Adelgid in a plantation setting responded to the insect with an array of induced resin volatile changes. Here we determine if eastern Hemlocks growing beneath a forest canopy respond to Hemlock Woolly Adelgid infestation with the same patterns of constitutive and inducible volatile resin production as those plantation specimens. We inoculated previously uninfested branches of mature and immature Hemlocks in a central New England forest with Hemlock Woolly Adelgid. We then sampled twig tissue of infested and uninfested trees in late spring, early summer, and mid-autumn, after known intervals of Adelgid activity when an induced response might be expected. We identified and quantified resin volatiles by gas chromatography-mass spectrometry. Constitutive levels of total monoterpenoids, sesquiterpenoids, and combined resin volatiles were all several-fold more abundant in forest trees than those previously measured in a plantation setting, pointing to further study of the influence of site factors on Hemlock volatile production. Hemlock Woolly Adelgid infestation induced an array of changes in eastern Hemlock's volatile profile, including many-fold increases in benzyl alcohol and methyl salicylate accumulation. Despite differences in constitutive concentrations of volatiles between the two sites, our findings verify that Hemlock Woolly Adelgid elicits patterns of resin volatile induction in forest-grown eastern Hemlocks quite similar to those previously observed in plantation grown trees.
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Density-Dependent Survival and Fecundity of Hemlock Woolly Adelgid (Hemiptera: Adelgidae)
Environmental Entomology, 2014Co-Authors: Elizabeth M. Sussky, Joseph S. ElkintonAbstract:ABSTRACT The Hemlock Woolly Adelgid (Adelges tsugae Annand) has decimated eastern Hemlocks (Tsuga canadensis Carriere) in forests throughout the eastern United Sates, but its densities in central NewEngland appear to have stabilized. To find out why, we infested 64 eastern Hemlocks with varying densities of Adelgid ovisacs in a typical eastern Hemlock forest in western Massachusetts. We subsequently documented Adelgid density, fecundity, and the amount of new growth on experimental trees over two consecutive years. We used a 2 by 2 randomized block design using previously and newly infested Hemlocks that were either 1-m tall saplings or branches of mature trees. There was a density-dependent decline in the survival and fecundity of Adelgid in both the spring and winter generations. This response was a function of both previous infestation by Adelgid and current year's crawler density in the spring generation. Additionally, the production of sexuparae in the spring generation played a key role in the overa...
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Terpene Chemistry of Eastern Hemlocks Resistant to Hemlock Woolly Adelgid
Journal of Chemical Ecology, 2014Co-Authors: E. Alexa Mckenzie, Evan L. Preisser, Joseph S. Elkinton, Richard A. Casagrande, Mark MayerAbstract:Recent studies have identified a small number of individual eastern Hemlock trees that demonstrate relative resistance to the introduced sap-feeding insect, the Hemlock Woolly Adelgid. Using gas chromatography, we compared concentrations of twenty-two terpenoids in susceptible and relatively resistant trees, both in the forest and in propagated cuttings in a common-garden setting. Terpenoid concentrations were higher in twig tissue of resistant versus susceptible trees, across six sampling dates and at both sites. These changes may be particularly important because the Hemlock Woolly Adelgid feeds on twig tissue. Because the common-garden cuttings were free of herbivores, the higher terpenoid concentrations are interpreted as a constitutive defense. Increased levels of monoterpenes and sesquiterpenes imply an overall increase in the input of carbon precursors to both terpenoid synthesis pathways.
Rusty Rhea - One of the best experts on this subject based on the ideXlab platform.
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Influence of Hemlock Woolly Adelgid Infestation Levels on Water Stress in Eastern Hemlocks within the Great Smoky Mountains National Park, U.S.A.
Forests, 2015Co-Authors: Carla Coots, Paris L. Lambdin, Jennifer Franklin, Jerome Grant, Rusty RheaAbstract:Extensive mortality of eastern Hemlock, Tsuga canadensis (L.) Carrière, resulting from infestation by Hemlock Woolly Adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), has occurred throughout the eastern United States. Although imidacloprid treatment can reduce tree mortality, its effectiveness can be influenced by several factors including tree water stress. The relationship between water stress and infestation rates is unknown, and an understanding of these could greatly increase the efficiency of management for this invasive insect. The primary objective of this study was to assess water stress at three levels of Hemlock Woolly Adelgid infestations. Water stress was measured monthly for 13 months in eastern Hemlocks classified as <25%, 25%–75%, and >75% infested. The highest level of water stress was found in those trees with Hemlock Woolly Adelgid infestation levels greater than 75%. The lowest level of water stress was found in those trees with less than 25% Hemlock Woolly Adelgid infestation levels. Knowledge of these effects can contribute to development of more effective chemical management strategies
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Influence of Hemlock Woolly Adelgid Infestation Levels on Water Stress in Eastern Hemlocks within the Great Smoky Mountains National Park, U.S.A.
Forests, 2015Co-Authors: Carla Coots, Jerome F. Grant, Paris L. Lambdin, Jennifer A. Franklin, Rusty RheaAbstract:Extensive mortality of eastern Hemlock, Tsuga canadensis (L.) Carriere, resulting from infestation by Hemlock Woolly Adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), has occurred throughout the eastern United States. Although imidacloprid treatment can reduce tree mortality, its effectiveness can be influenced by several factors including tree water stress. The relationship between water stress and infestation rates is unknown, and an understanding of these could greatly increase the efficiency of management for this invasive insect. The primary objective of this study was to assess water stress at three levels of Hemlock Woolly Adelgid infestations. Water stress was measured monthly for 13 months in eastern Hemlocks classified as 75% infested. The highest level of water stress was found in those trees with Hemlock Woolly Adelgid infestation levels greater than 75%. The lowest level of water stress was found in those trees with less than 25% Hemlock Woolly Adelgid infestation levels. Knowledge of these effects can contribute to development of more effective chemical management strategies.
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aerial application of the insect killing fungus lecanicillium muscarium in a microfactory formulation for Hemlock Woolly Adelgid suppression
In: McManus Katherine A; Gottschalk Kurt W. eds. 2010. Proceedings. 21st U.S. Department of Agriculture interagency research forum on invasive species, 2011Co-Authors: Scott Costa, Karen Felton, Bradley Onken, Richard Reardon, Rusty RheaAbstract:Forest populations of Hemlock Woolly Adelgid (HWA) were reduced using an operational formulation of the insect-killing fungus Lecanicillium muscarium when it was supported by microfactory formulation technology.
