Thesis (Ph. D.)--University of Tennessee, Knoxville, 2009. / Title from title page screen (viewed on Nov. 12, 2009). Thesis advisor: Scott E. Schlarbaum. Vita. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains ix, 122 p. : ill. (some col.), col. maps. Vita. Includes abstract. Includes bibliographical references.

Thesis (M.S.)--Ohio University, March, 2008. / Title from PDF t.p. Includes bibliographical references.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 2002. / Title from PDF t.p. (viewed on Dec. 10, 2005). Vita. Includes bibliographical references (p. 70-78).

Thesis (M.S.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains ix, 173 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references.

No description available.

Significant mortality of the invasive tree of heaven (TOH), Ailanthus altissima (Mill.) Swingle, was first observed in Pennsylvania in 2002 to be caused by an apparently host-specific strain of Verticillium albo-atrum Reinke & Berthold, a soil-borne, vascular wilt fungus. A limited survey conducted in Virginia revealed two sites where TOH stands were infected with V. albo-atrum. A virulence test confirmed that fungal isolates from both states were found to be highly pathogenic on TOH, killing all inoculated seedlings in 9 weeks. After overwintering, 11% (n = 37) of TOH root sections tested positive for V. albo-atrum, although the origin of the colonies was not identified. The pathogenicity of this pathogen suggests that it could be used together with host-specific insects for the biological control of TOH. A host-specific herbivorous weevil from China, Eucryptorrhynchus brandti Harold (Coleoptera: Curculionidae) that has been extensively studied as another potential biological control agent for TOH is currently pending quarantine release. Quarantine experiments were conducted to test different forms of transmission with E. brandti and V. albo-atrum simultaneously. In one experiment, 75% (n = 32) of adult E. brandti transmitted V. albo-atrum to TOH seedlings after walking on an actively growing culture and feeding on infected plant material. In another study after feeding on infected TOH stems for 24, 48 and 72 h, respectively, 16.7% (n = 120), 15.0% and 12.5% of adult E. brandti ingested and passed viable V. albo-atrum propagules into feces. Surviving weevils (83%, n = 20) overwintering in infested potting mix carried viable V. albo-atrum propagules externally. In addition, all weevil progeny that emerged from infected TOH billets appeared to be as healthy as weevils reared from non-infected billets and wild parents from China. Results from these laboratory studies indicate E. brandti has the ability to spread V. albo-atrum from tree to tree in a laboratory setting. / Master of Science in Life Sciences

The spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae), is a new invasive insect from Asia that is currently spreading in the Mid-Atlantic region of the US, where it has become a pest of economic concern for many industries in their invaded range. The purpose of this research was to document L. delicatula phenology in Virginia, their feeding impact to trees, and to test a rearing protocol in quarantine laboratory conditions. First, using field plots and weekly observational surveys, L. delicatula phenology was documented in 2019 and 2020 in Winchester, Virginia. I showed that L. delicatula were active from late April into November for each sampling year, and that the timing of life stage events varied only slightly between years. I also calculated cumulative average growing degree days for each life stage event using a lower developmental threshold of 10°C. Additionally, I confirmed that the host range of L. delicatula narrows as they progress through development. These results will help growers and land managers develop integrated pest management plans targeting L. delicatula. Second, dendrochronological methods were used to quantify L. delicatula feeding injury to Ailanthus altissima (Miller) Swingle (Sapindales: Simaroubaceae), Juglans nigra L. (Fagales: Juglandaceae), and Liriodendron tulipifera L. (Magnoliales: Magnoliaceae). Two sites in Pennsylvania that have experienced high populations and heavy feeding pressure from L. delicatula since 2016 were used to collect tree cores for analysis. I found evidence suggesting L. delicatula is capable of reducing the growth of A. altissima, but did not find the same evidence in the wood of the other tree species tested. Additionally, I found evidence that systemic insecticide treatments may reduce or prevent damage to A. altissima fed on by L. delicatula. Additional dendrochronological studies on the damage inflicted by L. delicatula feeding could shed light on the long-term impact of this new invasive tree pest. Lastly, a protocol for rearing L. delicatula was tested inside Virginia Tech's Insect Quarantine Laboratory. Three different cuttings of A. altissima (apical meristems, epicormic shoots, and field collected foliage) were tested to determine the best food source for L. delicatula in quarantine laboratory conditions. Overall, I did not find a significant difference between food treatments, however a greater proportion of third instars developed into fourth instars in the apical meristem treatment. I suggest future L. delicatula rearing research include the use of potted plants and/or multiple species. Though I had low success in rearing adult L. delicatula to produce egg masses, this method may prove useful for rearing early instars from eggs or sustaining field collected specimens for short durations. Research expanding our knowledge of L. delicatula will help us reach our goal of more effectively managing this pest species in the future. / Master of Science in Life Sciences / The spotted lanternfly, Lycorma delicatula (White), is a new invasive pest species impacting the eastern and northeastern regions of the United States. This insect uses its straw-like mouth parts to feed on the sap of many different plants including fruit trees, grapes, and several important ornamental and timber trees. Though they do not bite or sting, feeding can result in wilting, the growth of sooty mold, and sometimes plant mortality, making them an economic and nuisance pest in their invaded range. This research primarily focused on studying the timing of the spotted lanternfly's life cycle, feeding impact to trees, and a method for raising them in the laboratory for research purposes. The life-cycle of the spotted lanternfly was documented over two growing seasons in Winchester, VA and the timing of each life stage was shown to be similar between years. Additionally, it was confirmed that the spotted lanternfly feeds on fewer host species as it develops into an adult. Tree-ring analysis was used to identify spotted lanternfly feeding injury to tree-of-heaven, black walnut, and tulip poplar. I found evidence suggesting spotted lanternfly feeding can cause reduced growth in tree-of-heaven, but did not find similar evidence in the other species tested. A laboratory colony of spotted lanternflies would prove beneficial for additional research on this insect. I tested three different types of branches cut from the tree-of-heaven to identify the best food source for spotted lanternfly in laboratory conditions. The findings of this research will help develop pest management strategies to reduce the impact of this new pest in the US.

No description available.

Ailanthus altissima (Mill.) Swingle is a tree native to Asia that was intentionally introduced into the United States in the late eighteenth century. Ailanthus altissima has become an invasive species that has spread throughout most of North America. Lack of effective management tactics for suppression of A. altissima has lead to alternate control methods. Investigations into using biological control with the weevil Eucryptorrhynchus brandti were initiated in 2004. Studies were conducted to understand the general biology of E. brandti, rearing efficacy, and host specificity. Eucryptorrhynchus brandti is univoltine, has a life cycle similar to the closely related species Cryptorhynchus lapathi (L.), with 6 instars, and completes development in 126 ± 6.5 d at 25°C. Efficient egg to adult rearing was accomplished by caging 12 m and 12 f for 7 days on 23 – 92 cm long billets. Males and females can be differentiated by the structure of the metathoracic sternite and 1st abdominal segment. Host specificity experiments show that E. brandti preferentially feeds on North American A. altissima when tested against 29 species from 14 families. Larval development in the rare species Leitneria floridana Chapm. was apparent. Additional studies show that A. altissima does not occur across L. floridana distribution but may have the potential to invade L. floridana sites. / Ph. D.