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- Adelges tsugae (3)
- Fiorinia externa (2)
- Biological control (1)
- Chemical ecology (1)
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- Density-dependence (1)
- Entomology (1)
- Evolution (1)
- Hemlock woolly adelgid (1)
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- Massachusetts (1)
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Articles 1 - 4 of 4
Full-Text Articles in Life Sciences
Regional Comparison Of Overwintering Mortality, Fecundity, And Virulence In The Hemlock Woolly Adelgid, Artemis Demas Roehrig
Regional Comparison Of Overwintering Mortality, Fecundity, And Virulence In The Hemlock Woolly Adelgid, Artemis Demas Roehrig
Masters Theses 1911 - February 2014
Throughout the eastern United States, the spread of the hemlock woolly adelgid, Adelges tsugae Annand, has caused high mortality of eastern hemlocks Tsuga canadensis (L.). We recorded overwintering survival and fecundity of A. tsugae, and tree new growth at sites in the northeastern and southeastern United States and in a common garden experiment in Massachusetts.
Overwintering mortality of A. tsugae was much higher in the north (87%) than the south (37%) in 2009, and showed significantly positive density-dependence in the north only. In 2010, overwintering mortality decreased in both regions but remained higher in the north (54%) than the …
Resin Volatiles Of Eastern Hemlock Induced By Its Non-Native Herbivores, Joshua D. Pezet
Resin Volatiles Of Eastern Hemlock Induced By Its Non-Native Herbivores, Joshua D. Pezet
Masters Theses 1911 - February 2014
Eastern hemlock (Tsuga canadensis) is in decline because of infestation by the invasive hemlock woolly adelgid (Adelges tsugae; ‘HWA’) and, to a lesser extent, the elongate hemlock scale (Fiorinia externa; ‘EHS’). Many conifers respond to insect herbivory by inducing oleoresin-based defenses, however it is unknown whether eastern hemlock is capable of this inducible response. We conducted a plantation setting study of artificially infested saplings to determine if feeding by HWA or EHS induces changes in the tree’s volatile chemistry. The induced changes in volatiles we found were unlike the terpenoid-based defenses of related conifers. Only HWA feeding …
Interactions Between Pieris Oleracea And Pieris Rapae (Lepidoptera: Pieridae) Butterflies, And The Biological Control Agents Cotesia Glomerata And Cotesia Rubecula (Hymenoptera: Braconidae)., Megan V. Herlihy
Masters Theses 1911 - February 2014
Pieris oleracea, formerly Pieries napi, was once a widespread pierid butterfly in New England until the introduction of a biological control agent, Cotesia glomerata. It has been suggested that C. glomerata is responsible for the range reduction of P. oleracea. There are been several introductions of a second more specialized biological control agent, Cotesia rubecula, to the United States since the 1960’s. My first goal was to determine the current distribution and status of P. rapae parasitoids and the effectiveness of C. rubecula as a biological control agent since its release. The findings of a survey …
Density-Dependent Survival Of Hemlock Woolly Adelgid Life Stages, Elizabeth M. Sussky
Density-Dependent Survival Of Hemlock Woolly Adelgid Life Stages, Elizabeth M. Sussky
Masters Theses 1911 - February 2014
To investigate the density-dependent factors that may be partly responsible for the apparent stability of hemlock woolly adelgid (HWA; Adelges tsugae Annand) populations in central New England, we infested 64 eastern hemlock (Tsuga canadensis Carrière) trees with varying densities of HWA sistens ovisacs in a typical eastern hemlock forest in western Massachusetts. We subsequently documented HWA density, fecundity, and the amount of new growth on experimental trees over two consecutive years. We used a 2 x 2 randomized block design using previously and newly infested hemlocks divided into 1 m tall saplings and branches of mature trees. There was …