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Trends In Borrelia Spp. Prevalence In Ixodes Spp. Ticks From The Southeastern Coastal United States, Lauren Paul Maestas

Masters Theses

The Lyme borreliosis (LB) cycle, involving Ixodes scapularis and Borrelia burgdorferi sensu stricto (Bbss), is well documented in the northeastern US, where LB is becoming increasingly prevalent. In coastal North Carolina, I. affinis has been shown to have a higher incidence of Bbss than I. scapularis. My objectives were, to assess changes in prevalence of Bbss in Ixodes spp. along a transect from Virginia to Florida, and to assess the value of dogs and mesomammals as sentinels for spread of Borrelia burgdorferi sensu lato.

Ixodes spp. were collected at sites from 37.4^o N to 30.0^{o …}

Identification And Characterization Of Peak Activity, Environmental Variables, And Bacterial Pathogens In A. Americanum L. At Ames Plantation, West Tennessee, Brian Hendricks

Masters Theses

The status of tick-borne diseases (TBD) in the southeastern United States is uncertain due to a number of factors including, but not limited to emerging pathogens, misdiagnoses, and modifications to landscapes. Ehrlichiosis and rickettiosis are two of the most common TBDs; these are caused by Ehrlichia and Rickettsia bacteria that can be transmitted by a number of different tick species. The objectives of this study were to identify Amblyomma americanum (the Lone Star tick) peak activity and habitat preferences and characterize the potential role of A. americanum in tick-borne disease cycles in southwestern Tennessee. Using vegetation drags and CO_{2 …}

Intra- And Inter-Ear Compensation For Insect Injury To Field Corn, Zea Mays L., Sandra Jean Steckel

Masters Theses

Research was done in 2010 and 2011 at the West Tennessee Research and Education Center in Jackson, TN to investigate how southwestern corn borer, Diatraea grandiosella Dyar, (Lepidoptera: Crambidae), when infested at different densities and growth stages, affected the yield of infested, non-Bt corn plants and neighboring Bt plants. Infesting non-Bt corn plants with southwestern corn borer larvae caused significant injury. The number of larvae infested on plants and the timing of these infestations were factors that affected the amount of yield loss. There was little compensation by Bt plants that were adjacent to infested plants.

Other studies were done …

Molecular Systematics Of The Subfamily Phasiinae (Diptera: Tachinidae), Jeremy Daniel Blaschke

Masters Theses

The subfamily Phasiinae (Diptera: Tachinidae) is composed of obligate endoparasitoid flies that attack heteropteran insects, many of which are important agricultural pests. To lay a foundation for future studies in phasiine life history and their potential for use as biological control agents, the phylogenetic relationships within Phasiinae were explored using nucleotide sequences of two genes, CAD and LGL. A total of 63 taxa for CAD and 73 taxa for LGL were included in the analyses, representing 58 genera. Maximum likelihood inference methods were employed to reconstruct phylogenetic relationships in separate analyses of each gene and in a combined dataset. Phylogenetic …

Assessment Of Factors Affecting Establishment Of Biological Control Agents Of Hemlock Woolly Adelgid On Eastern Hemlock In The Great Smoky Mountains National Park, Abdul Hakeem

Doctoral Dissertations

Eastern hemlock in the Great Smoky Mountains National Park (GRSM) is threatened by hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae). To manage this invasive pest in GRSM, ca. 550,000 Sasajiscymnus tsugae (Sasaji and McClure) (Coleoptera: Coccinellidae) and 7,857 Laricobius nigrinus Fender (Coleoptera: Derodontidae) have been released. Limited information is available on their establishment in GRSM. To fill this gap, a study was initiated to assess establishment of these predators and their impact on hemlock health. To determine factors affecting establishment of these predators, 65 release sites were sampled from 2008 to 2012. Several factors were evaluated for their …

Characterization Of Field Evolved Resistance To Transgenic Cry1fa Maize In Spodoptera Frugiperda (J. E. Smith), Siva Rama Krishna Jakka

Doctoral Dissertations

Transgenic Bt crops expressing Cry and Vip toxins from Bacillus thuringiensis (Bt) have been increasingly planted to manage insect pest damage on agricultural crops. The high adoption of Bt-based insecticidal technologies suggests an increase selection pressure for the evolution of resistance in insect populations. So far, nine insect species have developed field evolved resistance to Bt crops, yet the mechanisms involved in field evolved resistance are unknown. In the present study, the resistance mechanism in field evolved resistance to maize producing Cry1Fa in Spodoptera frugiperda collected in fields from Puerto Rico was characterized. High levels of resistance to …

Ant Community Dynamics And The Effects Of Global Warming, Katharine Lisa Stuble

Doctoral Dissertations

This dissertation seeks to provide an understanding of how species coexist and, further, how climate change may alter communities by acting on the mechanisms that promote coexistence. Specifically, I examined coexistence among ant species in eastern deciduous forests and the effects that warming may have on foraging activity. Through a series of field observations, I sought evidence for the importance of four of the most commonly cited mechanisms for coexistence among ant species: the dominance – discovery tradeoff, the dominance – thermal tolerance tradeoff, spatial segregation, and niche partitioning. In this system, I did not find evidence for any of …

The Life History And Control Of Pityophthorus Juglandis Blackman On Juglans Nigra L. In Eastern Tennessee, Katheryne Avery Nix

Masters Theses

In the last decade, western states have experienced an increasing mortality rate in Juglans nigra L., black walnut, as a result of the fungal species Geosmithia morbida Kolařík et al. that results in numerous cankers that girdle the branches, resulting in dieback and tree mortality. The only known vector of G. morbida is the walnut twig beetle (WTB), Pityophthorus juglandis Blackman. This newly recognized disease/insect complex has been named Thousand Cankers Disease (TCD) due to the quantity of cankers produced by G. morbida.

Recently, TCD was discovered in the eastern U.S. To limit the spread of TCD in eastern …