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Revealing The Native Status Of Conyza Bonariensis: Specialization Of Insect Herbivores Associated With Conyza And Erigeron Spp. (Asteraceae) In Louisiana, Texas, And Mississippi, Carlos Wiggins
LSU Master's Theses
Flaxleaf fleabane [Conyza bonariensis (L.) Cronquist] (Asterales: Asteraceae) is an annual herb which grows up to 1.0 m in height and is native to South America. Due to introduction and subsequent development of herbicide resistance, C. bonariensis has become a major agricultural weed in Australia. The purpose of this study was to catalog herbivorous insects associated with local populations of C. bonariensis in Louisiana, Texas and Mississippi in order to establish comparisons with the Australian fauna and identify potential biological control agents. Leaves, roots, stems, and flowers of C. bonariensis were inspected for signs of insects and pathogens. Results …
Evaluation Of Winter Management Methods To Enhance Survival Of The Giant Salvinia Weevil, Cyrtobagous Salviniae, Lori Robyn Moshman
Evaluation Of Winter Management Methods To Enhance Survival Of The Giant Salvinia Weevil, Cyrtobagous Salviniae, Lori Robyn Moshman
LSU Master's Theses
Giant salvinia (Salvinia molesta Mitchell) is a noxious aquatic weed in the southeastern United States. Dense plant mats create ecological and economic consequences by displacing native species and impacting freshwater industries. Biological control programs using the salvinia weevil (Cyrtobagous salviniae Calder and Sands, Coleoptera: Curculionidae) have limited efficacy in giant salvinia’s northernmost range due to the weevil’s low cold tolerance and long-term establishment rates. Spunbonded polypropylene (SBP) fabrics and manipulation of plant density were evaluated as two strategies for managing giant salvinia mats during winter. Greenhouse, laboratory, and field experiments were conducted to determine the suitability of these …
Cold Tolerance And Overwintering Physiology Of The Salvinia Weevil (Cyrtobagous Salviniae): Improving The Biological Control Of Giant Salvinia In Temperate Louisiana, Alana D. Russell
LSU Master's Theses
Cyrtobagous salviniae is widely used for biological control of Salvinia molesta. Despite success in tropical and subtropical regions, the effectiveness of C. salviniae on S. molesta is inconsistent in temperate regions, indicating the need for a better understanding of the thermal biology of this agent. The objectives of this study were to compare cold tolerance of C. salviniae populations from the temperate native range and Louisiana, and characterize the overwintering physiology and population dynamics of C. salviniae in Louisiana. Surveys of the Lower Paraná-Uruguay Delta resulted in the first record of C. salviniae in Uruguay, and revealed the most southern …
Integrated Multiple-Tactic Management Of The Redbanded Stink Bug On Soybeans In Louisiana, Miyanda Nzala Moonga
Integrated Multiple-Tactic Management Of The Redbanded Stink Bug On Soybeans In Louisiana, Miyanda Nzala Moonga
LSU Doctoral Dissertations
Stink bugs (Hemiptera: Pentatomidae) are major pests of soybeans in Louisiana and heavy infestations often lead to economic losses. The stink bug species complex has changed in the past decade with the prevalence of the invasive redbanded stink bug, Piezodorus guildinii (Westwood), which causes greater damage than other stink bug species. Moreover, control of the redbanded stink bug has been faced with challenges because it is less sensitive to recommended insecticides. Therefore, studies were conducted to evaluate different control options for P. guildinii. Among the studies conducted was the current status of egg parasitoids of stink bugs in Louisiana. Telenomus …
Research In Biological Control Of The Formosan Subterranean Termite, Cai Wang
Research In Biological Control Of The Formosan Subterranean Termite, Cai Wang
LSU Doctoral Dissertations
The Formosan subterranean termite, Coptotermes formosanus Shiraki, is a worldwide distributed pest of wooden structures and living plants that causes huge economic losses. Compared to chemical pesticides, biological control may provide a more environmentally friendly and persistent method for the control of C. formosanus. In this research, a series of studies were conducted to understand the termite-pathogen interaction and to develop a feasible biological control strategy. In the first part of the research, the toxicity of Bt toxins expressed by genetically modified maize to termites was tested. Plant tissues or extracts of three commercially planted Bt maize and two non-Bt …
Introduction And Establishment Of Cyrtobagous Salviniae Calder And Sands (Coleoptera: Curculionidae) For The Control Of Salvinia Minima Baker (Salviniaceae), And Interspecies Interactions Possibly Limiting Successful Control In Louisiana, Katherine A. Parys
LSU Doctoral Dissertations
Common salvinia, Salvinia minima Baker, is a floating aquatic invasive macrophyte that obstructs waterways and causes problems in wetlands across Louisiana and Texas. The salvinia weevil, Cyrtobagous salviniae Calder and Sands, has been released in over 14 countries around the world for the biological control of Salvinia spp. We successfully monitored the introduction and establishment of C. salviniae on S. minima in southern Louisiana between 2006 and 2010. Cyrtobagous salviniae significantly lowered the biomass of S. minima and increased the number of terminal buds damaged but had no significant impact on pH, dissolved oxygen, conductivity, surface temperature, percent of surface …
Population Ecology Of Pseudacteon Tricuspis Borgmeier (Diptera: Phoridae), An Introduced Parasitoid Of The Red Imported Fire Ant Solenopsis Invicta Buren (Hymenoptera: Formicidae) In Louisiana, Donald Charles Henne
Population Ecology Of Pseudacteon Tricuspis Borgmeier (Diptera: Phoridae), An Introduced Parasitoid Of The Red Imported Fire Ant Solenopsis Invicta Buren (Hymenoptera: Formicidae) In Louisiana, Donald Charles Henne
LSU Doctoral Dissertations
Aspects of the population ecology of a parasitoid (Pseudacteon tricuspis) of the red imported fire ant (Solenopsis invicta) in Louisiana were studied. The spatio-temporal abundance patterns, dispersal, population spread, aggregation, direct mutual interference and functional response characteristics of this parasitoid were studied to address deficiencies in our knowledge about phorid flies, particularly Pseudacteon parasitoids. This endoparasitoid was discovered to manipulate host ant behavior in ways that benefit its own survival. Laboratory experiments to gain insights into behavioral and functional responses revealed that fly aggregations were density-dependent and interference was not significant when 1-3 females were simultaneously confined with hosts, although …
Evaluation Of Beauveria Bassiana And Host Plant Resistance For The Management Of Rice Stink Bug In Rice Agro-Ecosystem, Dilipkumar Thakorbhai Patel
Evaluation Of Beauveria Bassiana And Host Plant Resistance For The Management Of Rice Stink Bug In Rice Agro-Ecosystem, Dilipkumar Thakorbhai Patel
LSU Master's Theses
Isolates of Beauveria bassiana (Balsamo) Vuillemin were tested for biological control of rice stink bug, Oebalus pugnax (Fab.), in the laboratory, in small-plot field experiments compared with conventional insecticides, and in a large-plot experiment to determine the spread and persistence of the fungus. The soil-derived isolate LRC28 was more virulent to O. pugnax adults than the rice stink bug-derived isolate RSB in a laboratory experiment. The fungal isolates did not differ from one another in reducing insect numbers or in infecting rice stink bugs in the small-plot experiments. A single application of B. bassiana reduced rice stink bug nymphs on …
Screening And Characterization Of Pathogenic Fungi For Possible Control Of Coptotermes Formosanus, Jianzhong Sun
Screening And Characterization Of Pathogenic Fungi For Possible Control Of Coptotermes Formosanus, Jianzhong Sun
LSU Doctoral Dissertations
Coptotermes formosanus was used as “bait” to isolate pathogenic fungi from soil. Fifteen pathogenic fungal isolates were obtained, all either Metarhizium anisopliae (six isolates) or Beauveria bassiana (nine isolates). There were no differences in numbers of fungal isolates from the three sampling locations. However, significantly more isolates were found in woodlands (eleven) than in pastures (four). Median lethal doses (LD50s) of these fungal species to C. formosanus were interspersed, indicating that fungal isolates rather than species had the greatest effect on virulence. In vitro growth characteristics were significantly correlated with virulence against termites, suggesting that fungal virulence might be predicted …