Control Method for Invasive Aquatic Species introduced via Ballast Water: Effects of Carbon Dioxide Supersaturation on Survivorship of Digesia tigrina (Planaria: Maculata) and Lirceus brachyurus (Isopoda: Crustacea) Survivorship of an aquatic species of planaria (Digesia tigrina) and isopods (Lirceus barchyurus) to elevated levels of carbon dioxide (CO₂) was determined. Both planaria and isopods were exposed to levels of freshwater supersaturated with carbon dioxide, and percent mortality was calculated for various exposure durations, and at various pressure levels. The data collected were graphically analyzed to determine the time necessary to produce mortality in 50% (LT50) of any given sample of specimens tested at a certain pressure level. At 38.6 kPa, 103.4 kPa and 172.4 kPa, the LT50 for planaria was calculated to be 150.3 ± 10.1, 58.6 ± 11.1, and 27.8 ± 6.2 minutes, respectively. At 38.6 kPa, 103.4 kPa and 172.4 kPa , the LT50 for isopods was calculated to be 181.1 ± 52.5, 79.7 ± 21.9, and 40.5 ± 17.0 minutes, respectively. These results suggest that CO₂ supersaturation may be an easily applied, efficient method that would end the unwanted introduction of nonnative aquatic species to habitats via ballast water released from shipping vessels. Effect of High Hydrostatic Pressure Processing on Freely Suspended and Shellfish Associated T7 Bacteriophage The effectiveness of hydrostatic pressure processing (HPP) for inactivating viruses has only been evaluated in a limited number of studies and most of the work has been performed with freely suspended viruses. In this work, the inactivation of freely suspended, as well as shellfish associated bacteriophage T7, by HPP was studied. T7 was selected in hopes that it could potentially serve as a model for animal virus behavior. Both clams (Mercenaria mercenaria) and oysters (Crassostrea virginica) were homogeneously blended separately and inoculated with bacteriophage T7. The inoculated shellfish meat, as well as freely suspended virus samples, were subjected to HPP under the following conditions: 2, 4 and 6 min durations; 241.3, 275.8 and 344.7 Megapascals (MPa) pressure levels; and temperature ranges of 29.4 – 35, 37.8 – 43.3 and 46.1 – 51.7Ë C. Plaque forming unit (PFU) reductions of 7.8 log10 (100% inactivation) were achieved for freely suspended T7 at 344.7 MPa, 2 min and 37.8 – 43.3Ë C. At 46.1 – 51.7Ë C, T7 associated with either clams or oysters was inactivated at nearly 100% (> 4 log10) at all pressure levels and durations tested. The results indicated that T7 is readily inactivated by HPP under the proper conditions, may be protected or made more susceptible by shellfish meat, and may serve as a viable model for the response of several animal viruses to HPP. / Master of Science

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<p dir="ltr">In this era of changing global climate and globalization, the intricate relationships between non-native organisms and their impacts on forest health are of paramount concern. Bark and ambrosia beetles are diverse groups of insects that are among the most intercepted insects at international ports of entry. Once established, these insects can vector pathogens and disrupt functional forest dynamics. Bark and ambrosia beetles are known to attack various tree species, including black walnut (<i>Juglans nigra</i>), a valuable timer and nut-producing tree native to Eastern North America. Non-native woodboring beetles provide unique opportunities for ecological studies and pest management. This research investigates the chemical ecology and microbial dynamics in black walnut ecosystems to fill critical knowledge gaps and address the pressing issues surrounding forest health and sustainable management.</p><p dir="ltr">In Chapter 1, I review the current literature describing the use of semiochemicals in bark and ambrosia beetle management, non-native scolytines as vectors of phytopathogens, and the use of nematodes as natural antagonists of fungal pathogens in trees.</p><p dir="ltr">In Chapter 2, I aim to identify attractant and repellent semiochemicals for the ambrosia beetle <i>Anisandrus maiche</i>, which is a first step in developing effective management strategies for this species. I found that conophthorin and verbenone are strong repellents and that this beetle is attracted to ethanol in a dose-dependent manner.</p><p dir="ltr">In Chapter 3, I tested the hypothesis that <i>Anisandrus maiche </i>will be influenced by volatiles of its nutritional fungal symbiont, <i>Ambrosiella cleistominuta,</i> and that these compounds may synergize with ethanol. I identified seven unique compounds from the fungus and two fungal alcohols in the field. I found isobutyl alcohol to repel <i>A. maiche </i>while isoamyl alcohol has seasonal effects on <i>A. maiche </i>capture when paired with ethanol.</p><p dir="ltr">In Chapter 4, I aimed to characterize the assemblage of microorganisms residing on two non-native ambrosia beetles across diverse forest types. I tested the hypothesis that forest stand diversity and management regimes would affect the assemblage of microorganisms of ambrosia beetles. I found forest type influences the abundance of fungi and bacteria on <i>A. maiche </i>and <i>Xylosandrus crassiusculus</i> and that both beetle species transport genera of pathogenic fungi.</p><p dir="ltr">In Chapter 5, I test the hypothesis that inoculation with <i>Geosmithia morbida </i>alters the volatile profile of black walnut. I found one isolate of <i>G. morbida </i>induced changes in the volatile profile of black walnut bark and identified the compounds that changed relative to the control trees.</p><p dir="ltr">In Chapter 6, I tested the hypothesis that free-living fungivorous nematodes can modulate Thousand Cankers Disease severity. I found two genera of nematodes <i>Panagrolaimus </i>and <i>Aphelenchoides </i>to orient towards agents of the TCD system in Y-tube bioassays. <i>Aphelenchoides </i>sp. that were exposed to <i>G. morbida </i>grown on agar media augmented with black walnut bark extract significantly reduced <i>G. morbida </i>cankers in black walnut seedlings. This research has important implications for the management of TCD.</p><p dir="ltr">In Chapter 7, I summarize results from each of research chapter and discuss future research needs and directions to continue development of the knowledge surrounding chemical ecology and microbial dynamics of non-native scolytine beetles.</p>

京都大学 / 新制・論文博士 / 博士(農学) / 乙第13547号 / 論農博第2912号 / 新制||農||1101(附属図書館) / 学位論文||R5||N5428(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 大村 和香子, 教授 井鷺 裕司, 教授 今井 友也 / 学位規則第4条第2項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

<p> Chameleon plant (<em>Houttuynia cordata</em> Thunb.) is native to Southern and Southeastern Asia. It can reproduce sexually through seeds and asexually through rhizomes and is invasive in multiple countries including the U.S. There has been much research on <em>H. cordata</em> as a medicinal species, and its potential as an invasive species is well documented. However, its herbicidal resistance has not previously been quantified. The objective of this study is to assess <em>H. cordata’s </em>resistance to herbicides. This study consisted of two rounds of tests to examine the resistance of <em>H. cordata</em> plants to three commonly used herbicides: SpeedZone, Weed-B-Gon, and Roundup. Two concentrations of each herbicide were used during each trial in the study: the recommended concentration and twice the recommended concentration. Herbicide treatments were applied outside the greenhouse. Herbicides were sprayed uniformly on the plants until the herbicide was dripping off the leaves. The growth of the treated plants was then monitored in the greenhouse. The herbicides generally reduced growth of the plants temporarily. However, plant extermination was not achieved. Plant samples from all herbicidal treatments regrew from rhizomes after all herbicide treatments. Results from the study showed that <em>H. cordata </em>could not be controlled by the recommended concentrations of herbicides commercially available for horticultural uses in the U.S. Doubling the recommended herbicide concentration was also ineffective in exterminating <em>H. cordata </em>plants. This research clearly showed that <em>H. cordata</em> has the potential to become a highly invasive species with the potential to negatively affect the ecological integrity of many communities in the U.S.</p>

Across the central and eastern United States, upland oaks are experiencing regeneration complications. This thesis comprises two studies evaluating challenges in regenerating upland oaks. One study evaluates upland Quercus spp., Carya spp., and Acer rubrum L. response to prescribed fire and impacts on seedling growth and mortality. This study found prescribed fire promoted oak growth when canopy cover was < 77%. Oaks displayed lower percent mortality and higher resprout capacity after fire compared to red maple. The second study investigates impacts of Microstegium vimineum presence on Quercus alba L., Liriodendron tulipifera L., and Acer rubrum L. seedlings under different light and moisture environments. Microstegium vimineum presence decreased growth of both sweetgum and red maple; white oak was less impacted, likely because of its conservative growth strategy and high-water use efficiency. Oaks’ conservative growth strategy may offer more resiliency compared to its competitors in response to prescribed fire and Microstegium vimineum.

This thesis investigates the use of sequential parametric projection pursuits (SPPP) for hyperspectral dimensionality reduction and invasive species target recognition. The SPPP method is implemented in a top-down fashion, where hyperspectral bands are used to form an increasing number of smaller groups, with each group being projected onto a subspace of dimensionality one. Both supervised and unsupervised potential projections are investigated for their use in the SPPP method. Fisher?s linear discriminant analysis (LDA) is used as a potential supervised projection. Average, Gaussian-weighted average, and principal component analysis (PCA) are used as potential unsupervised projections. The Bhattacharyya distance is used as the SPPP performance index. The performance of the SPPP method is compared to two other currently used dimensionality reduction techniques, namely best spectral band selection (BSBS) and best wavelet coefficient selection (BWCS). The SPPP dimensionality reduction method is combined with a nearest mean classifier to form an automated target recognition (ATR) system. The ATR system is tested on two invasive species hyperspectral datasets: a terrestrial case study of Cogongrass versus Johnsongrass and an aquatic case study of Waterhyacinth versus American Lotus. For both case studies, the SPPP approach either outperforms or performs on par with the BSBS and BWCS methods in terms of classification accuracy; however, the SPPP approach requires significantly less computational time. For the Cogongrass and Waterhyacinth applications, the SPPP method results in overall classification accuracy in the mid to upper 90?s.

The purpose of this research was to increase understanding of ecology and control of cogongrass (Imperata cylindrica (L.) Beauv.) to assist with management of this invasive grass. To address different aspects of cogongrass management, I examined factors that affect spread of cogongrass, effects of cogongrass on native plant communities, and use of three native species to suppress cogongrass. Relative susceptibility of pine-bluestem and pine-shrub vegetation associations to vegetative encroachment and seed dispersal of cogongrass were evaluated. Vegetative encroachment into burned and unburned areas of these two vegetation associations also was measured. Effects of infestation size on vegetative growth of cogongrass and relationships between military activity and establishment and growth of cogongrass on military firing points were investigated. I also compared frequency of cogongrass infestation and vegetative growth rates for unpaved roads with different levels of traffic and maintenance. Native plant richness, diversity, and abundance were compared between cogongrass infestations and in uninfested adjacent areas for longleaf pine-bluestem and ruderal, cleared areas. Morella cerifera (L.) Small, Chamaecrista fasciculata (Michx.) Greene, and Panicum virgatum L. were tested for their ability to suppress cogongrass re-growth after treatment with a herbicide. Mean vegetative encroachment of cogongrass was < 2 m/yr for both habitat types regardless of burning. Vegetative encroachment was more than double in burned plots compared to unburned plots. Spikelets of cogongrass consistently dispersed farther into pine-bluestem (x¯ =17.3 m) forests compared to pine-shrub forests (x¯ = 9.4 m). Vegetative encroachment was not affected by size of infestation for cogongrass patches on firing points (x¯ < 1 m/yr) (P > 0.643). In areas of soil disturbance from military equipment, vegetative expansion rates of 7-10 m/yr were recorded. There was a positive relationship between military troop use and cogongrass establishment for one of the 2 years of the study (P = 0.023). Growth and establishment of cogongrass did not vary for unpaved roads with differing levels of maintenance and traffic (P > 0.173). Species diversity and abundance of herbaceous vegetation was less in cogongrass infestations compared to uninfested adjacent areas. Complete suppression of cogongrass was not evident for any of three native species tested.

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