Date of Award


Document Type



Environmental and Forest Biology

Thesis Advisor

Thomas Horton


Invasive insects pose serious threats to native host tree species as well as the habitat they invade. Intense and sometimes irreversible ecological situations are created with establishment of invasive insect species. Hemlock woolly adelgid (HWA, Adelges trugae Annand) is an invasive insect that has caused widespread mortality of eastern hemlock, Tsuga canadensis, (L.) Carr. Ectomycorrhizal (EM) fungi form mutualistic relationships with eastern hemlock and symbiotic species are threatened by HWA. The purpose of this study was to investigate impacts from hemlock woolly adelgid on EM fungi by counting ectomycorrhizal root tips as well as using molecular techniques for fungal identification. Soil samples were gathered at four different sites, two infested sites and two healthy (control) sites. Results obtained indicate a slightly statistically significant reduction in the abundance of ectomycorrhizal root tips produced in infested sites. Molecular techniques identified a diverse array of fungal species from all sites with five ectomycorrhizal species and one non-mycorrhizal species identified. The genus Russula was present in both treatments, but most likely were different species. Reduction of ectomycorrhizal root tips is evident; however, some species still persist with intense infestation of HWA.