| two invasive herbivores on a shared host: patterns and consequences of phytohormone induction. | herbivore-induced changes in host quality mediate indirect interactions between herbivores. the nature of these indirect interactions can vary depending on the identity of herbivores involved, species-specific induction of defense-signaling pathways, and sequence of attack. however, our understanding of the role of these signaling pathways in the success of multiple exotic herbivores is less known. eastern hemlock (tsuga canadensis) is attacked by two invasive herbivores [elongate hemlock scale ... | 2018 | 29362885 |
| self-regulation in populations of the elongate hemlock scale, fiorinia externa (homoptera: diaspididae). | the presence of numerical self-restraints in populations of the elongate hemlock scale, fiorinia externa ferris (homoptera: diaspididae), was investigated by determining the effects of scale density on development rate, fecundity, mortality, and dispersal. evidence indicates that populations are, to some extent, numerically self-regulated on eastern hemlock, tsuga canadensis (l) carr. development rate, fecundity and survival for two consecutive years were all negatively correlated with scale den ... | 1979 | 28309375 |
| foliar terpenoids in tsuga species and the fecundity of scale insects. | the relationship between the reproductive success of two japanese scale insects, fiorinia externa ferris and nuculaspis tsugae (marlatt) (homoptera: diaspididae) and the concentrations of 15 terpenoids in needles of tsuga sieboldii, the japanese host, and t. canadensis, the north american host, was investigated during 1981 and 1982 in a field plot of 8-year-old trees in new haven, ct, usa. both scales produced significantly more eggs per female on t. sieboldii than on t. canadensis. stepwise mul ... | 1984 | 28311012 |
| insect guild structure associated with eastern hemlock in the southern appalachians. | an assessment of the insect guild structure associated with immature and mature eastern hemlock, tsuga canadensis (l.) carrière, at high and low elevations was made before the invasion by the hemlock woolly adelgid, adelges tsugae (annand), and elongate hemlock scale, fiorinia externa ferris. guild dynamics were determined among 243 insect species associated with eastern hemlock in the southern appalachians. detritivore, hematophage, herbivore, fungivore, parasitoid, predator, scavenger, and tra ... | 2007 | 18284768 |
| effects of hemlock woolly adelgid and elongate hemlock scale on eastern hemlock growth and foliar chemistry. | in the eastern united states, two invasive specialist insects share a native host plant, eastern hemlock, tsuga canadensis. in recent years, much research has focused on the impacts of the hemlock woolly adelgid (adelges tsugae) because of the detrimental effects it has on hemlock growth and survival. in contrast, the invasive elongate hemlock scale (fiorinia externa) is thought to have only minor impacts on hemlock. we infested hemlock saplings with each insect and compared them with control (i ... | 2010 | 20388282 |
| optimizing a basal bark spray of dinotefuran to manage armored scales (hemiptera: diaspididae) in christmas tree plantations. | the armored scales fiorinia externa ferris and aspidiotus cryptomeriae kuwana (hemiptera: diaspididae) are increasingly damaging to christmas tree plantings in southern new england. the systemic insecticide dinotefuran was investigated for selectively suppressing armored scale populations relative to their natural enemies in cooperating growers' fields in 2008 and 2009. banded soil application of dinotefuran resulted in poor control. however, a dinotefuran spray applied to the basal 25 cm of tru ... | 2010 | 21061974 |
| variation in plant defense against invasive herbivores: evidence for a hypersensitive response in eastern hemlocks (tsuga canadensis). | herbivores can trigger a wide array of morphological and chemical changes in their host plants. feeding by some insects induces a defensive hypersensitive response, a defense mechanism consisting of elevated h(2)o(2) levels and tissue death at the site of herbivore feeding. the invasive hemlock woolly adelgid adelges tsugae ('hwa') and elongate hemlock scale fiorinia externa ('ehs') feed on eastern hemlocks; although both are sessile sap feeders, hwa causes more damage than ehs. the rapid rate o ... | 2011 | 21573865 |
| entomopathogenic fungi associated with exotic invasive insect pests in northeastern forests of the usa. | mycopathogens of economically important exotic invasive insects in forests of northeastern usa have been the subject of research at the entomology research laboratory, university of vermont, for the last 20 years. elongate hemlock scale, european fruit lecanium, hemlock woolly adelgid and pear thrips were analyzed for the presence of mycopathogens, in order to consider the potential for managing these pests with biological control. fungal cultures isolated from insects with signs of fungal infec ... | 2013 | 26462527 |
| host plant associations of an entomopathogenic variety of the fungus, colletotrichum acutatum, recovered from the elongate hemlock scale, fiorinia externa. | a fungal epizootic has been detected in populations of the scale fiorinia externa ferris (hemiptera: diaspididae) in the eastern hemlock, tsuga canadensis (l.) carrière (pinales: pinaceae), of several northeastern states. colletotrichum acutatum simmonds var. fioriniae marcelino and gouli var. nov. inedit (phyllachorales: phyllachoraceae), a well-known plant pathogen, was the most commonly recovered fungus from these infected scales. this is the second report of a colletotrichum sp. infecting sc ... | 2009 | 19613851 |
| entomopathogenic activity of a variety of the fungus, colletotrichum acutatum, recovered from the elongate hemlock scale, fiorinia externa. | a fungal epizootic in populations of fiorinia externa ferris (hemiptera: diaspididae) infesting hemlock trees, tsuga canadensis (l.) carrière (pinales: pinaceae) in forests of the northeastern us has been recently detected. the current known distribution of the epizootic spans 36 sites in new york, pennsylvania, new jersey and connecticut. colletotrichum acutatum simmonds var. fioriniae marcelino and gouli var. nov. inedit. (phyllachorales: phyllachoraceae) was the most prevalent fungus recovere ... | 2009 | 19613442 |
| exploitative competition between invasive herbivores benefits a native host plant. | although biological invasions are of considerable concern to ecologists, relatively little attention has been paid to the potential for and consequences of indirect interactions between invasive species. such interactions are generally thought to enhance invasives' spread and impact (i.e., the "invasional meltdown" hypothesis); however, exotic species might also act indirectly to slow the spread or blunt the impact of other invasives. on the east coast of the united states, the invasive hemlock ... | 2008 | 18959304 |
| metarhiziopsis microspora gen. et sp. nov. associated with the elongate hemlock scale. | a sporodochial fungus collected from the elongate hemlock scale, fiorinia externa (ferris) in coventry, connecticut, is described. this fungus has characteristics of both metarhizium and myrothecium but develops setae surrounding white to buff sporodochia and dry conidia in chains, a combination of characters found in neither genus. phylogenetic analyses of the complete small subunit ribosomal dna (ssu), partial ef1-alpha, and complete 5.8s ribosomal dna and internal transcribed spacers (its) 1 ... | 2008 | 18751553 |
| colletotrichum acutatum var. fioriniae (teleomorph: glomerella acutata var. fioriniae var. nov.) infection of a scale insect. | an epizootic has been reported in fiorinia externa populations in new york, connecticut, pennsylvania and newjersey. infected insects have profuse sclerotial masses enclosing their bodies. the most commonly isolated microorganism from infected f. externa was colletotrichum sp. a morphological and molecular characterization of this fungus indicated that it is closely related to phytopathogenic c. acutatum isolates. isolates of colletotrichum sp. from f. externa in areas of the epizootic were simi ... | 2008 | 18751543 |
| exotic herbivores on a shared native host: tissue quality after individual, simultaneous, and sequential attack. | plants in nature are often attacked by multiple enemies whose effect on the plant cannot always be predicted based on the outcome of individual attacks. we investigated how two invasive herbivores, the hemlock woolly adelgid (adelges tsugae) (hwa) and the elongate hemlock scale (fiorinia externa) (ehs), alter host plant quality (measured as amino acid concentration and composition) when feeding individually or jointly on eastern hemlock (tsuga canadensis), an important long-lived forest tree tha ... | 2012 | 22311255 |
| false ring formation in eastern hemlock branches: impacts of hemlock woolly adelgid and elongate hemlock scale. | herbivores can alter plant physiology through the induction of abnormal wood formation. feeding by some insects induces the formation of false rings, a band of thick-walled latewood cells within the earlywood portion of the tree ring that reduces water transport. hemlock woolly adelgid (adelges tsugae annand) and elongate hemlock scale (fiorinia externa ferris) are invasive insects that both feed on eastern hemlock [tsuga canadensis (l.) carrière]. adelges tsugae has a greater effect on tree hea ... | 2012 | 22732610 |
| hemlock woolly adelgid and elongate hemlock scale induce changes in foliar and twig volatiles of eastern hemlock. | eastern hemlock (tsuga canadensis) is in rapid decline because of infestation by the invasive hemlock woolly adelgid (adelges tsugae; 'hwa') and, to a lesser extent, the invasive elongate hemlock scale (fiorinia externa; 'ehs'). for many conifers, induced oleoresin-based defenses play a central role in their response to herbivorous insects; however, it is unknown whether eastern hemlock mobilizes these inducible defenses. we conducted a study to determine if feeding by hwa or ehs induced changes ... | 2013 | 23900803 |