Thesis (Ph. D.) -- Lincoln University, 2008. / Includes case study of Argentine ant in New Zealand. Also available via the World Wide Web.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 115-118). Also available on the World Wide Web.

Thesis (M.C.M.) -- Lincoln University, 2010. / Also available via the World Wide Web.

MSc., Faculty of Science, University of the Witwatersrand, 2011 / Both indigenous “Tamarix usneoides” and alien T. ramosissima co-occur in South Africa. Tamarix usneoides is potentially a metal and salt phytoremediation species. However, hybridisation is occurring between the two species and hybrids growth characteristics are deemed to be invasive. This study was undertaken at two sites on one Highveld gold mine, characterised by different soil types, where plant growth, reproductive potential and insect abundance and diversity were measured. This aims to establish the growth of T. usneoides in two site-species trials, and to identify differences between Tamarix taxa that are consistent across different environmental conditions and can be used for identification. This study also set out to establish if higher reproductive effort and enemy release are promoting the invasiveness of T. ramosissima. Trees in one site (a water logged, clayey “Glenrosa” soil) displayed significantly greater percentage survival, growth and reproductive effort than trees in the other site (a well drained, sandy “Hutton” soil). Extensive hybridisation between T. usneoides and T. ramosissima was observed with two hybrid states, morphologically similar to each parent species. The reproductive effort is consistently greater in T. ramosissima and T. ramosissima hybrid than T. usneoides and T. usneoides hybrid. After sampling 217 trees in this study, the three characteristics of (1) insertion of filaments into the nectar disc, (2) petal shape and (3) presence of salt glands on leaves most accurately distinguished between T. usneoides and T. ramosissima taxa. Three insect species have been identified from this study as potentially damaging agents on Tamarix spp. Insects can discern between the Tamarix tree taxa and T. ramosissima is being released from insect herbivore pressure, as very few insects and a lower diversity were recorded on T. ramosissima and its hybrids (T. ramosissima hybrids > T. ramosissima). To achieve phytoremediation objectives, careful tree identification and selection of genetically pure individuals for cloning is recommended. Additionally the removal of existing alien and hybrid plants, and further research to find a suitable host specific insect biological agent to control alien Tamarix is necessary.

The commercial forest industry in South Africa is predominantly dependent on large tracts of exotic monoculture plantations. While this simplifies management practice, there is always the inherent danger posed by introduced pests and diseases. Classical biological control is usually the most effective control method against introduced exotic pests. Climatic factors and seasonal differences may negatively affect the ability of the natural enemies to establish successfully at the new location. Successful establishment of the natural enemies usually results in control over the pest within four years. Sirex noctilio naturally occurs in the mediterranean countries of Europe and North Africa. It is the only member of the Siricid family capable of killing living pine trees. Sirex noctilio was accidentally introduced into New Zealand from Europe during the early 1900s. It has since been found in Australia, Brazil, Argentina South Africa and Chile. Initial biological control in New Zealand and Tasmania was through the release of Siricid specific parasitoid wasps from Europe and North America. The discovery of the accidental introduction of the entomophagous nematode Beddingia siricidicola and its subsequent artificial culturing for release provided the platform for the biological control methodology, which brought the Sirex woodwasp under control. The methods and natural enemies used in New Zealand and Australia were introduced by the South American countries and in the Western Cape of South Africa. Successful biological control was achieved in the Western Cape within two years after the initial introduction of the nematode B. siricidicola. The migration of S. noctilio into the summer rainfall regions of South Africa occurred in the absence of the associated natural enemies. This resulted in rapid population growth of the pest and substantial damage was caused to plantations of Pinus patula in the Eastern Cape and KwaZulu-Natal. Initial attempts at introducing B. siricidicola during 2004 were not very successful. This study contributes to the understanding and adaptation of the biological control methods to the summer rainfall climate. The key finding was that in the summer rainfall climate, only the bottom third of nematode inoculated S. noctilio infested trees produced parasitized adults during the emergence period. A comparative study was done on log samples from S. noctilio infested trees collected in the Western Cape and KwaZulu-Natal. iv An adapted nematode inoculation technique for pulpwood plantations in the summer rainfall regions was developed and implemented in mass inoculations with B. siricidicola during 2007 and 2008. Locally available herbicides were tested for suitability of use in the establishment of trap trees, which would attract ovipositing S. noctilio females in situations where low numbers of the woodwasp occur. Determination of the levels of natural B. siricidicola parasitism in S. noctilio adults during the 2008 emergence period indicate successful establishment of the nematode in KwaZulu-Natal. Successful introduction of the parasitoid wasp Ibalia leucospoides into the summer rainfall regions has also been achieved.

Nutria are semi-aquatic rodents, non-native to Oregon. They are an invasive species that damage stream banks with burrowing and cause destruction of native vegetation; activity that may cause deterioration of stream water quality. I hypothesized that my study's duration and pattern of nutria trapping along South Johnson Creek would be sufficient to lead to a significant change in turbidity, dissolved oxygen (DO), total dissolved solids (TDS), total solids (TS), and total suspended solids (TSS).

The Argentine black and white tegu, Salvator merianae, is a nonnative species that has invaded parts of Florida. The potential impacts of this species on native Florida wildlife are not yet known. This study looks at the stomach contents of 169 S. merianae captured between 2011 and 2013 in south Florida to infer potential impacts of S. merianae and spatial or seasonal shifts in diet. Analysis of 169 GI tracts showed that S. merianae is an omnivorous, terrestrial forager with a broad dietary range which includes insects, fruits, plants, snails, crayfish, carrion, birds, small mammals, turtles, snakes, lizards, frogs and eggs. S. merianae diet composition varied with capture habitat, the fattest tegus were collected from disturbed/agricultural areas and these samples contained, primarily, gastropods and insects. Tegu dietary habits threaten local endangered and state listed species such as the American crocodile, Crocodylus acutus, and the Cape Sable seaside sparrow, Ammodramus maritimus mirabilis. Dedicated funds and efforts need to be focused on this species to limit its further spread and future impact on native species. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

The Brazilian pepper tree (BP, Schinus terebinthifolius), introduced to the United States in the 1800s, has since become a category one invasive plant in Florida, aggressively spreading to 3000 km2 of prime habitat. There is a serious dearth of knowledge on whether the rhizobiome plays any roles in the displacement of native flora and the range expansion of BP. This thesis discusses the well-established plant invasion mechanisms of the BP and highlights key emerging mechanisms and gaps in (a) the current understanding of the molecular, below-ground processes of BP invasion and (b) studies on the potential role of microbial interactions in the success of BP invasion already established for other select invasive species, and the intervention of soil metagenomic studies to elucidate plant invasive mechanisms. These poorly studied mechanisms could further explain the aggressive spread and resilience of BP and contribute significantly to the development of effective and sustainable control measures, enabling appropriate strategies for restoring native plants. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

No description available.

In Quebec, the swede midge (Contarinia nasturtii), a newly invasive pest, was found for the first time in 2003. During a two year study (2004-2005) I studied the seasonal development of the swede midge, the presence of natural enemies and tested entomopathogenic nematodes for its control. Results showed that the overwintering generation of the swede midge emerged during the second half of June. Based on adult captures and abundance of larvae in the field, there were three to four overlapping generations. Late transplants were more heavily attacked by the swede midge and broccoli and cauliflower were the most susceptible crops. No parasitoids were found in the experimental sites during either year of the study and two polyphagous coccinellid predators (Harmonia axyridis and Coccinella septempunctata) were field-collected for further evaluation under laboratory conditions. Although these two coccinellid species fed on swede midge larvae in plastic containers, further experiments demonstrated that H. axyridis was not able to prey on swede midge larvae on infested broccoli plants. The susceptibility of swede midge larvae to three species of entomopathogenic nematodes (Steinernema feltiae, S. carpocapsae, and Heterorhabditis bacteriophora) was also evaluated in laboratory assays. Heterorhabditis bacteriophora was the only species that caused significant mortality to swede midge larvae and, at a concentration of 1000 IJs/larva, caused 90-100% mortality in loam, sandy loam, clay and muck soil. This is the first study describing the seasonal development of the swede midge in Quebec. In addition, the potential use of entomopathogenic nematodes as biological control agents against the swede midge is demonstrated.