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The adelgids (Adelgidae) are a small family of sap-feeding insects, which, together with true aphids (Aphididae) and phylloxerans (Phylloxeridae), make up the infraorder Aphidomorpha. Some adelgid species are highly destructive to forest ecosystems such as Adelges tsugae , Adelges piceae , Adelges laricis , Pineus pini , and Pineus boerneri. Despite this, there are no high-quality genomic resources for adelgids, hindering advanced genomic analyses within Adelgidae and among Aphidomorpha. Here, we used PacBio continuous long-read and Illumina RNA-sequencing to construct a high-quality draft genome assembly for the Cooley spruce gall adelgid, Adelges cooleyi (Gillette), a gall-forming species endemic to North America. The assembled genome is 270.2 Mb in total size and has scaffold and contig N50 statistics of 14.87 and 7.18 Mb, respectively. There are 24,967 predicted coding sequences, and the assembly completeness is estimated at 98.1 and 99.6% with core BUSCO gene sets of Arthropoda and Hemiptera, respectively. Phylogenomic analysis using the A. cooleyi genome, 3 publicly available adelgid transcriptomes, 4 phylloxera transcriptomes, the Daktulosphaira vitifoliae (grape phylloxera) genome, 4 aphid genomes, and 2 outgroup coccoid genomes fully resolves adelgids and phylloxerans as sister taxa. The mitochondrial genome is 24 kb, among the largest in insects sampled to date, with 39.4% composed of noncoding regions. This genome assembly is currently the only genome-scale, annotated assembly for adelgids and will be a valuable resource for understanding the ecology and evolution of Aphidomorpha. [ABSTRACT FROM AUTHOR]

The paper elaborates theoretical basis of the origin of aphid cyclical parthenogenesis in view of the original life of these insects in strobiloid galls on Picea spp. The period of gall opening is greatly extended in time, which prevents normal panmixia and creates a selective advantage for parthenogenetic reproduction. Migration of aphids to secondary host plants, on which closed galls never form, parthenogenetic reproduction on these plants, and the subsequent simultaneous return of "remigrants" to the main host plant make it possible to synchronize the development of the bisexual generation and achieve mass panmixia at the end of the life cycle only; it coincides with the end of summer growth shoots or the autumn end of the vegetation period as a whole. The evolutionary transition of aphids from conifers to angiosperms in the Cretaceous period in parallel meant the possibility of development in more spacious galls accommodating several consecutive parthenogenetic generations, the transition to viviparity and telescopic embryonization, significantly accelerating the propagation. [ABSTRACT FROM AUTHOR]

Moericke traps are commonly used to monitor pests in agriculture and at the same time, they have gradually been applied in forestry. Therefore, four Moericke traps were placed in two fir stands (Valšovice, Czech Republic) to investigate the spectrum and intensity of aphidomorphic insects between 2019 and 2021. The traps were consistently positioned at a height of two meters in the monitored stands throughout the monitoring period. Each stand was evaluated separately, and their distribution differences were compared to the nearest Johnson-Taylor suction trap in the locality called Věrovany. A total of 400 samples were collected over three years, out of which 1,674 specimens belonging to 111 species or genera, classified into three families (Aphididae, Adelgidae, and Phylloxeridae), were analyzed. The eudominant species found in these stands was Phyllaphis fagi, while the dominant species was Mindarus abietinus. Additionally, 11 species or genera were identified as subdominant, 5 species as recedents, and the remaining species fell under the category of subrecessive. It means that the majority of the captured specimens was not from fir trees but from undergrowth, adjacent stands, or other woody species. [ABSTRACT FROM AUTHOR]

The hemlock woolly adelgid (Adelges tsugae (Annand)) is a serious invasive pest of hemlock trees in eastern North America. Multiple biological control agents have been the focus of research aimed at pest management and conserving hemlock communities. Three promising A. tsugae specialist predators are the beetle Laricobius nigrinus (Fender) (Coleoptera: Derodontidae) and flies in the genus Leucotaraxis (Diptera: Chamaemyiidae), Leucotaraxis argenticollis (Zetterstedt), and Leucotaraxis piniperda (Malloch). However, these flies are vulnerable to parasitism by wasps in the genera Pachyneuron (Walker) (Hymenoptera: Pteromalidae) and Melanips (Walker) (Hymenoptera: Figitidae). This study explores parasitoid wasp interactions with these Leucotaraxis species in their native western North American range and potential impacts on the biological control program in the East. Leucotaraxis , La. nigrinus , and parasitoid emergences were observed from adelgid-infested foliage collected from Washington State and British Columbia in 2018, 2019, and 2020. Undescribed species of Pachyneuron and Melanips emerged from puparia as solitary parasitoids. Parasitoid emergence was positively correlated with Leucotaraxis emergence. Percent parasitism increased between February and July, with the months of June and July experiencing higher parasitoid emergence than Leucotaraxis. Differences in emergence patterns suggest that Pachyneuron may be more closely associated with Le. argenticollis as a host, and that Melanips may be associated with Le. piniperda. High parasitism in Leucotaraxis had no effect on La. nigrinus larval abundance, whereas the combined emergence of parasitoids and Leucotaraxis was positively correlated with La. nigrinus. This suggests that there is limited competition among these predators. [ABSTRACT FROM AUTHOR]

Partial sequences of COI and EF-1α of nine aphid species of the family Adelgidae and partial sequences of 16S rRNA of their endosymbiotic bacteria were used to reveal co-evolutionary relationships between endosymbiotic bacteria and their aphid hosts in Lithuania. In addition to currently recognized taxa of gamma- and beta-proteobacterial endosymbionts ("Candidatus Vallotia", "Candidatus Profftia", "Candidatus Annandia", "Candidatus Hartigia", "Candidatus Ecksteinia", "Candidatus Steffania" and "Candidatus Gillettellia") of Adelgidae, new gamma-proteobacterial (Sodalis-allied) endosymbionts were detected in Adelges (Aphrastasia) pectinatae and Pineus cembrae. Cophylogenetic analyses based on aphid partial COI and EF-1α sequences and 16S rRNA gene fragment of their endosymbiotic bacteriae showed reliable cophylogenetic events confirming the importance of host aphid species relatedness in structuring symbiont communities of adelgid aphid species. Molecular aphid species delimitation analyses based on Bayesian phylogenies of aphid COI and EF-1α and bacterial 16S rRNA fragments indicate adelgid species complexes Adelges (Adelges) laricis - Adelges (Adelges) tardus, Adelges (Gilleteella) cooleyi - Adelges (Gilleteella) coweni, Adelges (Dreyfusia) nordmannianae - Adelges (Dreyfusia) piceae, Adelges (Sacchiphantes) abietis - Adelges (Sacchiphantes) viridis and Pineus pini - Pineus orientalis representing single species each. [ABSTRACT FROM AUTHOR]

Laricobius nigrinus Fender (Coleoptera: Derodontidae), a predatory beetle native to western North America, has been released since 2003 for management of hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae), a non-native pest killing hemlocks in eastern North America. Over 420,000 L. nigrinus have been released in the eastern USA from field and lab-reared sources, 14,000 of which were deployed in the Commonwealth of Virginia, USA. In order to determine the establishment rates of L. nigrinus in Virginia, surveys were conducted in 2017 and 2018 at all release sites within this state. During the study, stand-level HWA densities were estimated, and hemlock tree health and predator–prey ratios were quantified. The identification of Laricobius spp. recoveries were made using microsatellite analysis. During the period of the study, L. nigrinus were found to have established at 82% of Virginia release sites and were the primary species recovered (80%). Both Laricobius rubidus (18%) and hybrids (2%) were also recovered. Stand-level HWA densities varied greatly over sites and years but showed a general decline in year two of the study. Establishment at such a high percentage of release sites suggests that the climate in Virginia is suitable for the predator and the insect is adaptable to the wide variety of site conditions where hemlocks typically grow. [ABSTRACT FROM AUTHOR]

Based on the original research of 2017–2018, also reference data, four aphid species and five species complexes of the family Adelgidae listed for Lithuanian fauna. Pineus (Pineus) strobi (Hartig, 1839) is a new species for the fauna of Lithuania. Summarized information on the distribution and host specificity of adelgid species in Lithuania is presented. The most common species recorded from all geographical regions of Lithuania were the ones belonging to the species complexes Adelges laricis – A. tardus, Pineus orientalis – P. pini, Sacchiphantes viridis – S. abietis and Gilletteella cooleyi – G. coweni. Six species of Adelgidae inhabit host plants of the genus Picea, three live on Larix, three – on Pinus, two – on Abies, one – on Pseudotsuga. Partial sequences of mitochondrial (COI) and nuclear (EF-1α) DNA of Lithuanian samples were analysed in comparison with available data from GeneBank representing samples from Central Europe. Pairwise distances of COI and EF-1α fragments between samples belonging to species complexes Adelges laricis – A. tardus, Dreyfusia nordmannianae – D. piceae, Sacchiphantes viridis – S. abietis, Gilletteella cooleyi – G. coweni and Pineus orientalis – P. pini suggest each species complex being a single species. [ABSTRACT FROM AUTHOR]

The article discusses the article ‘‘Media representation of hemlock woolly adelgid (HWA) management risks: a case study of sciencecommunication and invasive species control,'' by Leppanen et al. in the September 18, 2018 issue and mentions limitations to media reporting of science. Topics discussed include biological control of HWA, potential non-target impacts of HWA biological control agents, and efficency of biological control agents.

Eastern U.S. forests are witnessing an ecologically disruptive decline in one of the region's distinctive foundation tree species, the eastern hemlock (Tsuga canadenis). The exotic insect pests hemlock woolly adelgid (Adelges tsugae, HWA) and elongate hemlock scale (Fiorinia externa) have greatly altered many forest ecosystems previously dominated by this important evergreen conifer. The consequences for ecosystem processes are far reaching because hemlock is often replaced by deciduous tree species, such as black birch (Betula lenta), which have strongly divergent effects on forest floor microenvironments and nutrient cycling. We took advantage of an accidental experiment initiated by patch-level timber harvesting ~30 yr ago to investigate how the removal of hemlock, and its replacement by deciduous trees, has affected leaf litter characteristics, soil organic layer mass, C:N content, and soil respiration rates. We also contrasted these areas to nearby forest plots where deciduous B. lenta has been dominant for almost a century. The inclusion of healthy, intact hemlock stands in the design, and the close proximity of plots, allowed for a powerful space-for-time approach to detect ecosystem changes that are likely to occur across the broader landscape with HWA-induced hemlock loss in coming years. Three years of data collection from a series of plots in hemlock, young birch, and mature birch stands revealed dramatic differences in soil carbon pools and cycling. Between forests dominated by hemlock vs. mature birch, we saw a significant decrease in soil organic layer mass and in the C:N of the remaining organic material. Although hemlock and young birch stands showed no significant differences in soil respiration rates, mature birch stands had significantly higher soil respiration rates throughout the entire growing season, regardless of wet or dry years. Our results suggest that the carbon pool in the forest floor is likely to mobilize through greater decomposition with a 6.89 decline in soil organic layer C storage as hemlocks are replaced by deciduous trees, leading to a potential net release of ~4.5 tons C per hectare. We conclude that the ramifications of this change for carbon storage could be extensive, but may take decades to manifest. [ABSTRACT FROM AUTHOR]

Nutritional bacterial symbionts enhance the diets of sap-feeding insects with amino acids and vitamins missing from their diets. In many lineages, an ancestral senior symbiont is joined by a younger junior symbiont. To date, an emergent pattern is that senior symbionts supply a majority of amino acids, and junior symbionts supply a minority. Similar to other hemipterans, adelgids harbor obligate symbionts, but have higher diversity of bacterial associates, suggesting a history of symbiont turnover. The metabolic roles of dual symbionts in adelgids and their contributions to the consortium are largely unexplored. Here, we investigate the symbionts of Adelges tsugae, the hemlock woolly adelgid (HWA), an invasive species introduced from Japan to the eastern United States, where it kills hemlock trees. The response of hemlocks to HWA feeding has aspects of a defensive reaction against pathogens, and some have speculated that symbionts may be involved. We sequenced the genomes of "Ca. Annandia adelgestsuga" and "Ca. Pseudomonas adelgestsugas" symbionts to detail their metabolic capabilities, infer ages of relationship, and search for effectors of plant defenses. We also tested the relationship of "Ca. Annandia" to symbionts of other insects. We find that both symbionts provide nutrients, but in more balanced proportions than dual symbionts of other hemipterans. The lesser contributions of the senior "Ca. Annandia" support our hypothesis for symbiont replacements in adelgids. Phylogenomic results were ambiguous regarding the position of "Ca. Annandia". We found no obvious effectors of plant defenses related to insect virulence, but hypothetical proteins in symbionts are unknown players. [ABSTRACT FROM AUTHOR]

Keys and diagnoses of North European aphids (Hemiptera, Aphidoidea) feeding on conifers are given, including species from nearby areas of Central and Western Europe, based on live and freeze-dried material. Externally visible informative characters, such as body shape, colours, wax coating, and pigmentation pattern are utilized, in addition to characters traditionally used in the literature. Rich illustrations with photographs of live colonies and freeze-dried specimens, supported by drawings where needed, are presented. The combination of colour images and diagnoses, utilizing easily observed characters, allows the identification of a large number of species already in the field, and many more at home with the aid of a stereo microscope. Host plant relationships and aphid-ant associations are presented.

In the eastern United States, hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae) is considered an invasive pest of eastern hemlocks; an ecologically foundational tree species. Current management of HWA focuses on chemical and biological controls, with recent research suggesting that these two tactics could be integrated successfully. The approach is to protect a subset of hemlocks with systemic insecticides while releasing predatory insects onto adjacent, unprotected trees. The goal of this study was to assess the effects of chemical and biological control tactics, alone and in combination, on hemlock health and HWA densities at three southern Appalachian sites (KY, WV, and TN) from 2010 to 2016. Although insecticide applications were effective at protecting individual trees, none of the overall treatments (chemical, biological, or combined) had a significant effect on tree health or HWA population index values relative to untreated plots. Tree health generally declined at all sites over time. HWA populations were highly variable over time and were likely more strongly influenced by extremely low, winter temperatures than by the treatments. Cross-correlation analysis of tree health and HWA population indicated a time-lag effect. At two of the three sites, recovery of tree health lagged 0 – 3 years behind decline in HWA population, and decline in HWA populations lagged approximately 0 – 1 years behind decline in tree health. The predatory beetle, Laricobius nigrinus , was recovered two-years, post-release at the KY and WV sites in 2012 and 2013, but was not recovered from the TN site. The lack of sustained recovery of L. nigrinus may be attributable to the occurrence of extremely low, winter temperatures in 2014 and 2015, which produced subsequent crashes in the HWA populations. In TN, the L. nigrinus population may have been unrecoverable due to a decline in the HWA population shortly after initial release. [ABSTRACT FROM AUTHOR]

The pine bark adelgid, Pineus strobi Hartig (Hemiptera: Adelgidae), is a native herbivore of eastern white pine, Pinus strobus L. (Pinales: Pinaceae), in eastern North America. P. strobi does not appear to have any dominant overwintering lifestage in southwest Virginia, as it does in its northern range. Eggs can be found consistently from late March through early December and may be produced sporadically later throughout the winter during warm periods. Two distinct generations were observed in the spring, after which life stage frequencies overlapped. Adult body size varied seasonally and was greatest in the spring. The present study constitutes the first recording of phenological details of the P. strobi in its southern range, informing biological control efforts aimed at closely related invasive pests. The phenological plasticity observed between northern and southern P. strobi populations provides insight into the potential effects of climate on the population dymanics of this and related species. [ABSTRACT FROM AUTHOR]

We explore and expand on the morphological term digitule. The term was originally proposed for toe-like setae on a species of Phylloxera Boyer de Fonscolombe, 1834 (Hemiptera, Sternorrhyncha, Aphidomorpha) by Henry Shimer, an American naturalist. While it is standard terminology in scale systematics (Hemiptera, Sternorrhyncha, Coccidomorpha), the term digitule was ignored by aphid specialists despite being the original taxon for which the term was described. Similar setae occur on many arthropod groups, so the homology is poorly understood even within any superfamily of Hemiptera. We provide the etymology of the term, a proposed explanation for why it was used among scale taxonomists and not aphid taxonomists, and discuss briefly options to progress beyond the confusion between terminology for morphology and homology in Sternorrhyncha. [ABSTRACT FROM AUTHOR]

Sap-sucking insects typically engage in obligate relationships with symbiotic bacteria that play nutritional roles in synthesizing nutrients unavailable or in scarce supply from the plant-sap diets of their hosts. Adelgids are sap-sucking insects with complex life cycles that involve alternation between conifer tree species. While all adelgid species feed on spruce during the sexual phase of their life cycle, each adelgid species belongs to a major lineage that feeds on a distinct genus of conifers as their alternate host. Previous work on adelgid symbionts had discovered pairs of symbionts within each host species, and unusual diversity across the insect family, but left several open questions regarding the status of bacterial associates. Here, we explored the consistency of symbionts within and across adelgid lineages, and sought evidence for facultative vs. obligate symbiont status. Representative species were surveyed for symbionts using 16S ribosomal DNA gene sequencing, confirming that different symbiont pairs were consistently present within each major adelgid lineage. Several approaches were used to establish whether symbionts exhibited characteristics of long-term, obligate mutualists. Patterns of symbiont presence across adelgid species and diversification with host insects suggested obligate relationships. Fluorescent in situ hybridization and electron microscopy localized symbionts to bacteriocyte cells within the bacteriome of each species (with one previously known exception), and detection of symbionts in eggs indicated their vertical transmission. Common characteristics of long-term obligate symbionts, such as nucleotide compositional bias and pleomorphic symbiont cell shape were also observed. Superimposing microbial symbionts on the adelgid phylogeny revealed a dynamic pattern of symbiont gains and losses over a relatively short period of time compared to other symbionts associated with sap-sucking insects, with each adelgid species possessing an older, "senior" symbiont and a younger "junior"symbiont.A hypothesis relating adelgid life cycles to relaxed constraints on symbionts is proposed, with the degradation of senior symbionts and repeated acquisition of more junior symbionts creating opportunities for repeated colonization of new alternate-conifer hosts by adelgids. [ABSTRACT FROM AUTHOR]

To determine if key attributes for a successful biological control agent are possessed by the predator, Laricobius nigrinus Fender, field studies were conducted in its native range of Seattle, WA. The relationship between adult and immature L. nigrinus abundance to different densities of its prey, Adelges tsugae Annand, were determined. In a second study, predator and prey densities, and survivorship of each sistens A. tsugae stage were determined to gauge the impact of predation. The predator strongly aggregated and increased its reproduction when prey density increased, the two mechanisms of a numerical response. Immature predator-prey ratios were high and average prey density was low in comparison with invaded areas of the eastern United States. Survivorship of aestivating first-instar sistens A. tsugae was low and survivorship of each instar (second, third, and fourth) and adults was high and increased with each stage. When pooled, however, the survivorship of sistens second instar-ovisac stages was low primarily owing to L. nigrinus larval consumption of ovisacs. In its native range, L. nigrinus has key attributes of a successful biological control agent, such as a strong numerical response, high predator-prey ratios, and an important larval impact on A. tsugae populations. Demographic data could serve as important benchmarks for future studies to determine if L. nigrinus and other predators can regulate densities of A. tsugae below eastern hemlock's physiological damage threshold in the eastern United States. [ABSTRACT FROM AUTHOR]

The sequence diversity in the mitochondrial cytochrome-c oxidase I (COI) gene was evaluated as a tool for resolving differences among species of European adelgids collected from several localities across the Czech Republic. Members of 7 genera and 16 species were examined, and as outgroups, two species of Phylloxeridae were used. Sequence divergences within species were on average less than 0.15%, whereas divergences between species ranged from 0.0 to 4.12% for congeneric and to 13.24% for intergeneric comparisons. It is concluded that DNA barcoding of Adelgidae is a powerful tool for identifying genera, but at the species level it works only in those cases where there are no species complexes. Nevertheless, it can be used as a complement to traditional, morphological taxonomy.

As a measure of cold hardiness, we tested the supercooling points or freezing temperatures of individual hemlock woolly adelgids (Adelges tsugae Annand) collected from 15 locations across the north to south range of the adelgid in eastern North America at different times during two winters. Adelgids from the northern interior locations with USDA hardiness zones of 5B-6B had lower supercooling points than adelgids from more southern or more coastal locations (zones 7A and 6B), where minimum winter temperatures were higher. Supercooling points reached a minimum in February in northern but not in southern locations. Laboratory experiments demonstrated that adelgids exposed to colder temperatures (-12 °C) had lower supercooling points after 3 d and adelgids held at 10 °C had higher supercooling points than did adelgids held at 2 °C for the same period. Extending these periods to 7 d produced no further change in supercooling points. Adelgids at northern sites had much lower supercooling points in February 2015 following at least 10 d of much colder weather than adelgids from those same sites in February 2016 following much warmer weather. The induction of cold hardiness produced much year-to-year variation in cold hardiness, especially in northern sites, in addition to concurrently and previously demonstrated genetic differences in cold hardiness between northern and southern adelgid populations. Consequently, the cold temperatures required to kill hemlock woolly adelgids will vary year to year and week to week based on exposure to prior temperatures. [ABSTRACT FROM AUTHOR]

Systemic imidacloprid is the most widely used insecticide to control the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), an exotic pest of eastern hemlock, Tsuga canadensis (L.) Carriére in the United States. This study was conducted to 1) determine the effect of treatment timing (spring vs. fall) and application method (trunk injection vs. soil injection) on the spatial and temporal distribution of imidacloprid within the crown of A. tsugae-free eastern hemlock using a competitive enzyme-linked immunosorbent assay (ELISA), 2) compare ELISA to gas chromatography-mass spectrometry (GC/MS) for the detection of imidacloprid in xylem fluid, and 3) determine the concentration of imidacloprid in leaf tissue using high performance liquid chromatography with tandem mass spectrometric (LC/MS/MS) detection methods. Xylem fluid concentrations of imidacloprid were found to be significantly higher for spring applications than for fall applications and for trunk injections than soil injections in the first year posttreatment. A total of 69% of samples analyzed by ELISA gave 1.8 times higher concentrations of imidacloprid than those found by GC/MS, leading to evidence of a matrix effect and overestimation of imidacloprid in xylem fluid by ELISA. A comparison of the presence of imidacloprid with xylem fluid and in leaf tissue on the same branch showed significant differences, suggesting that imidacloprid moved intermittently within the crown of eastern hemlock. [ABSTRACT FROM AUTHOR]

Stand thinning is being tested as a means to limit the impacts of the invasive hemlock woolly adelgid (HWA; Adelges tsugae Annand) on eastern hemlock ( Tsuga canadensis (L.) Carriere). The efficacy of this strategy may be reduced if thinning increases hemlock foliar nutrients because HWA densities are correlated with foliar concentrations of N, P, K, Ca, and Mn. We determined foliar N, P, K, Ca, and Mn concentrations in 1-year-old and all other (older) needles prior to and for 4 years after thinning in northwestern Pennsylvania stands of eastern hemlock without HWA. Average foliar concentrations in 1-year-old needles were 1.30-1.80 g N·100 g−1, 1300-1700 mg P·kg−1, 4200-6300 mg K·kg−1, 2500-5200 mg Ca·kg−1, and 2393 μg Mn·g−1. N, P, and K decreased, Ca increased, and Mn first increased and then stabilized. Thinning by itself did not affect the tested foliar nutrients. The interaction between treatment and year was significant and evident in temporal trajectories of foliar N and K. However, the differences between thinned and unthinned plots within years averaged only 0.03 g N·100 g−1 and 340 mg K·kg−1. We concluded that even though thinning changed the temporal trajectories of foliar N and K, the nutritional shifts were minimal, brief, and unlikely to affect the efficacy of thinning in limiting the impacts of HWA. [ABSTRACT FROM AUTHOR]

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The hemlock woolly adelgid, Adelges tsugae Annand is an invasive insect that frequently causes hemlock ( Tsuga spp.) mortality in the eastern United States. Studies have shown that once healthy hemlocks become infested by the adelgid, nutrients are depleted from the tree, leading to both tree decline and a reduction of the adelgid population. Since A. tsugae is dependent on hemlock for nutrients, feeding on trees in poor health may affect the ability of the insect to obtain necessary nutrients and may consequently affect their physiological and population health. Trees were categorized as lightly or moderately impacted by A. tsugae based on quantitative and qualitative tree health measurements. Population health of A. tsugae on each tree was determined by measuring insect density and peak mean fecundity; A. tsugae physiological health was determined by measuring insect biomass, total carbon, carbohydrate, total nitrogen, and amino nitrogen levels. Adelges tsugae from moderately impacted trees exhibited significantly greater fecundity than from lightly impacted trees. However, A. tsugae from lightly impacted hemlocks contained significantly greater levels of carbohydrates, total nitrogen, and amino nitrogen. While the results of the physiological analysis generally support our hypothesis that A. tsugae on lightly impacted trees are healthier than those on moderately impacted trees, this was not reflected in the population health measurements. Adelges tsugae egg health in response to tree health should be verified. This study provides the first examination of A. tsugae physiological health in relation to standard A. tsugae population health measures on hemlocks of different health levels. [ABSTRACT FROM AUTHOR]

Eastern hemlock (Tsuga canadensis [L.] Carriére) in the United States is threatened by the invasive hemlock woolly adelgid (Adelges tsugae Annand). The native hemlock looper (Lambdina fiscellaria Guenée) also appears to have played a role in previous population declines of this conifer. Although these two insects co-occur in much of the adelgid's invaded range, their interactions remain unstudied. We assessed looper performance and preference on both uninfested and adelgid-infested foliage from adelgid-susceptible hemlocks, as well as on uninfested foliage from an eastern hemlock that is naturally adelgid-resistant. Larvae reared on uninfested foliage from adelgid-susceptible hemlocks experienced 60% mortality within the first two weeks of the experiment, and pupated at a lower weight than larvae fed adelgid-infested foliage. Despite differences in foliage source, this first look and strong pattern suggests that the hemlock looper performs better (pupates earlier, weighs more) on adelgid-infested foliage. In addition, trends suggested that larvae reared on foliage from the adelgid-resistant tree survived better, pupated earlier, and weighed more than in the other treatments. Larvae preferred adelgid-resistant over adelgid-susceptible foliage. Our results suggest that looper perform slightly better on adelgid-infested foliage and that plant resistance to xylem-feeding adelgid may increase susceptibility to foliar-feeding looper larvae. [ABSTRACT FROM AUTHOR]

Tsuga canadensis (Eastern Hemlock) and T. caroliniana (Carolina Hemlock) are important components of western North Carolina forests. The invasive Adelges tsugae (Hemlock Woolly Adelgid [HWA]) was first reported in NC in 1995, and by 2007 the entire range of hemlock in the state was infested. An examination of the Forest Inventory and Analysis (FIA) program data for FIA Unit 4 (21 mountainous counties in western North Carolina), looking at remeasured trees for the time period 1999-2013, demonstrated that diameter net growth of hemlock decreased and mortality increased with increasing duration of HWA infestation. Hemlock trees in this study had a ∼50% chance of survival after 12 years of confirmed HWA infestation in the county where they occur, and growth of surviving trees was reduced by ∼50% over the same time period. This study demonstrates the utility of FIA data for examining effects of an introduced, invasive pest on tree growth and mortality over a relatively small area. Some advantages and limitations to our approach are discussed. [ABSTRACT FROM AUTHOR]

Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae) was brought to the United States from China as a potential biological control agent for hemlock woolly adelgid (Adelges tsugae Annand) (Hemiptera: Adelgidae). Scymnus camptodromus phenology is closely synchronized with that of A. tsugae and has several characteristics of a promising biological control agent. As a prerequisite to field release, S. camptodromus was evaluated for potential nontarget impacts. In host range studies, the predator was given the choice of sympatric adelgid and nonadelgid prey items. Nontarget testing showed that S. camptodromus will feed to some degree on other adelgid species, but highly prefers A. tsugae. We also evaluated larval development of S. camptodromus on pine bark adelgid (Pineus strobi (Hartig)) (Hemiptera: Adelgidae) and larch adelgid (Adelges laricis Vallot) (Hemiptera: Adelgidae); a small proportion of predator larvae was able to develop to adulthood on P. strobi or A. laricis alone. Scymnus camptodromus showed no interest in feeding on woolly alder aphid (Paraprociphilus tessellatus Fitch) (Hemiptera: Aphididae) or woolly apple aphid (Eriosoma lanigerum (Hausmann)) (Hemiptera: Aphididae), and minimal interest in cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) in choice and no-choice experiments. Scymnus camptodromus females did not oviposit on any host material other than A. tsugae-infested hemlock. Under the circumstances of the study, S. camptodromus appears to be a specific predator of A. tsugae, with minimal risk to nontarget species. Although the predator can develop on P. strobi, the likelihood that S. camptodromus would oviposit on pine hosts of this adelgid is small. [ABSTRACT FROM AUTHOR]

A taxonomic and nomenclatural Catalogue of the adelgids (Hemiptera: Adelgidae) is presented. Six family- group names are listed, five being synonyms of Adelgidae. Twenty-two genus-group names, of which nine are subjectively valid and in use, are presented with their type species, etymology, and grammatical gender. One hundred and six species-group names are listed, of which 70 are considered subjectively valid. [ABSTRACT FROM AUTHOR]

Invasive herbivores can cause widespread dieback of naïve native hosts in the invaded range. Some consume leaves, some bore through wood, whereas others, such as piercing-sucking insects, alter plant resource allocation through changes to source-sink dynamics and depletion of long-term stores. Invasive sap-sucking herbivores that target cells critical to resource transport and storage may have particularly large effects. Herbivory by two exotic hemipterans, hemlock woolly adelgid ( HWA), Adelges tsugae Annand ( Adelgidae), and elongate hemlock scale ( EHS), Fiorinia externa Ferris ( Diaspididae), have very different effects on eastern hemlock, Tsuga canadensis ( L.) Carrière ( Pinaceae). Although these insects differ in both timing and feeding site on their hemlock host, the reasons for their differential effects are poorly understood. Here, using potted seedlings in a common garden, we examined the effects of these two herbivores on resource uptake and allocation immediately after an initial attack. We labeled the plants with a single pulse of 13CO2 and a supply of 15NH415NO3 every third day to obtain a whole-plant perspective on resource uptake and allocation. After 10 weeks of controlled infestation, plants were measured and divided into tissue types (needles, branches, main stem, and roots). In each tissue we quantified biomass, 13C, 15N, total carbon (C), nitrogen (N), protein, and starch pools. Hemlock woolly adelgid feeding decreased new needle biomass by 34%, increased 13C allocation to roots and main stems by 130%, and increased 15N allocation to old foliage by 18%. Hemlock woolly adelgid infestation also resulted in increased starch storage in old branches over new needles, and marginally increased protein content plant-wide. Elongate hemlock scale infestation resulted in a different growth pattern, with a 27% increase in biomass allocation to the main stem. Elongate hemlock scale also caused a 23% increase in N allocation to roots and main stem. Increases in resource allocation to main stem and belowground may indicate herbivore-induced changes to storage patterns, or compensatory increased fine root growth to facilitate nutrient and water uptake. These resource allocation effects likely underlie the rapid and dramatic decline of hemlock in response to HWA feeding, and the considerably milder effects of EHS feeding. [ABSTRACT FROM AUTHOR]

The valid scientific name for the hemlock woolly adelgid is affirmed to be Adelges tsugae Annand. A discrepancy between the names Adelges funitectus (Dreyfus) and A. tsugae in the historical literature is investigated and resolved. The generic (or subgeneric) name Aphrastasia should not be applied to Adelges tsugae, as this species is not closely related to Adelges pectinatae (Cholodkovsky), the type species of Aphrastasia. We propose Annandina subgen. nov. for A. tsugae. [ABSTRACT FROM AUTHOR]

Adelgids (Hemiptera) in the genusPineushave been reported as introduced insect pests causing serious losses toPinusplantations worldwide. In 2008,Pineus boerneriwas recorded for the first time in Colombia, with infestations noted onPinus kesiya,P. tecunumanii,P. maximinoiandP. oocarpa. The lack of information on this insect in Colombia prompted investigations of its life cycle and infestation levels as well as host susceptibility of the mainPinusspecies planted in Colombia. In addition, the possibility of using aCeraeochrysaspecies, an already established predator of adelgids in Colombia, for biological control was considered. Results showed thatPineus boerneriin Colombia has an anholocyclic life cycle comprised of four instars with a complete duration of between 49 and 97 d. Infestations were higher in the middle and upper part of trees.Pinus kesiyaandP. maximinoihad the highest levels of susceptibility in field as well as in greenhouse trials. A survey of naturally infested trees showedP. tecunumaniito be moderately susceptible, whereasP. patulaandP. oocarpahad low levels of susceptibility in a greenhouse trial but were not susceptible in the field. Investigations considering the impact of predation ofCeraeochrysaspecies showed a high predation rate of up to 140P. boernericonsumed per day by a singleCeraeochrysaindividual. Other predators ofP. boerneriwere recorded but were not sufficiently common to warrant detailed study. [ABSTRACT FROM AUTHOR]