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Dissertations / Theses on the topic 'Aquatic weed'

Author: Grafiati

Published: 4 June 2021

Last updated: 26 July 2025

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1

Castro, Rodrigo Martinez [UNESP]. "Estudo comparativo das perdas d'água em mesocosmos colonizados ou não por Aguapé (Eichhornia crassipes (Mart.) Solms-Laubach." Universidade Estadual Paulista (UNESP), 2008. http://hdl.handle.net/11449/86352.

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Made available in DSpace on 2014-06-11T19:22:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-01-18Bitstream added on 2014-06-13T19:48:23Z : No. of bitstreams: 1 castro_rm_me_botfca.pdf: 7107653 bytes, checksum: 61a50230ec66c506c741fa342395e15d (MD5)<br>Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)<br>Clicar acesso eletrônico abaixo.

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Castro, Rodrigo Martinez. "Estudo comparativo das perdas d'água em mesocosmos colonizados ou não por Aguapé (Eichhornia crassipes (Mart.) Solms-Laubach /." Botucatu : [s.n.], 2008. http://hdl.handle.net/11449/86352.

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Resumo: Clicar acesso eletrônico abaixo.<br>Orientador: Edivaldo Domingues Velini<br>Coorientador: Fernando Tadeu de Carvalho<br>Banca: Luis Fernando Nicolosi Bravin<br>Banca: Robinson Antonio Pitelli<br>Mestre

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3

Wakelin, Sarah Catherine. "A quantitative and qualitative assessment of stormwater retention basisns, relationships in nature and response to three aquatic weed control methods." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0014/MQ41645.pdf.

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4

Clements, Daniel. "Optimising the management of invasive aquatic plants targeted for extirpation from catchments and waterways : Utilising alligator weed (Alternanthera philoxeroides (Mart.) Griseb.) as a target species." Thesis, Federation University Australia, 2017. http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/157567.

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Aquatic plants are integral components of freshwater ecosystems and provide essential ecosystem services. However, when invasive species establish in new aquatic environments, there are few natural checks and balances to inhibit their growth and spread. Overabundant aquatic vegetation can harm aquatic systems if left unchecked and negatively impact on agricultural productivity, social amenity and biodiversity values. Prevention and early intervention are recognised as the most cost effective means to manage invasive species that pose a biosecurity risk. This thesis contributes to the developme

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Martins, André Trevizoli [UNESP]. "Diquat no manejo de aguapé Eichhornia crassipes (Mart.) Solms e seu impacto sobre fatores limnológicos." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/99920.

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Made available in DSpace on 2014-06-11T19:30:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-08Bitstream added on 2014-06-13T19:39:59Z : No. of bitstreams: 1 martins_at_dr_botfca.pdf: 1083872 bytes, checksum: a814be883a3e40cb442935dc71aaa611 (MD5)<br>Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)<br>As macrófitas, apesar da enorme importância na dinâmica do ambiente aquático, quando formam extensas e densas colonizações promovem uma série de prejuízos ao ambiente e aos usos múltiplos dos reservatórios. Nestas situações, há a necessidade de redução de seu ta

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Martins, André Trevizoli 1975. "Diquat no manejo de aguapé Eichhornia crassipes (Mart.) Solms e seu impacto sobre fatores limnológicos /." Botucatu : [s.n.], 2009. http://hdl.handle.net/11449/99920.

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Resumo: As macrófitas, apesar da enorme importância na dinâmica do ambiente aquático, quando formam extensas e densas colonizações promovem uma série de prejuízos ao ambiente e aos usos múltiplos dos reservatórios. Nestas situações, há a necessidade de redução de seu tamanho populacional, seja reduzindo as condições favoráveis ao crescimento, seja por meio do controle direto das plantas. Dentre as macrófitas aquáticas que proporcionam estes tipos de problemas, o aguapé (Eichhornia crassipes (Mart.) Solms) é considerada como a mais importante. O diquat tem sido muito utilizado para o controle d

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Thomas, Caitlin B. "Survival and Growth Responses of Lithobates Pipiens Tadpoles to anHerbicide and an Algaecide used to Control Aquatic Invasive Plants." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1435688702.

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8

Nelson, Kristen Marie. "EVALUATING THE MYTH OF ALLELOPATHY IN CALIFORNIA BLUE GUM PLANTATIONS." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1643.

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It is widely accepted that allelopathy is not only significant, but more or less singular, in the inhibition of understory vegetation in California Eucalyptus globulus (blue gum) plantations. However, there is no published documentation of allelopathy by blue gums against California native species. Here, we present evidence that germination and early seedling growth of five California native species are not inhibited by chemical extracts of blue gum foliage, either at naturally-occurring or artificially concentrated levels. In the greenhouse, seeds were germinated in field-collected soil from

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9

Zawawi, Mouafaq Abbas. "Biology of Phragmites australis (Cav.) Trin. ex Steudel." Thesis, Bangor University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315009.

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10

Janes, Rachel Ann. "The biology and control of Azolla filiculoides Lam. and Lemna minuta Kunth." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260362.

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The aim of this study was to improve our understanding of the biology of two alien, invasive, free-floating species, the Water Fern Azollafiliculoides and the Least Duckweed Lemna minUla, which cause severe weed problems in Britain. Hence, control practices, which had been based upon anecdotal information, could be given a scientific foundation. An appraisal of the known distributions of the two species in Britain was undertaken. From an analysis of spread to date, it can be predicted that L. minUla will be present in 150 and A.filiculoides in 500, 10 x 10 km grid squares by the year 2000. Nei

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11

Weidow, Elliot D. "Genetic Diversity in an Invasive Clonal Plant? A Historical and Contemporary Perspective." ScholarWorks@UNO, 2018. https://scholarworks.uno.edu/td/2522.

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Introduced populations of Eichhornia crassipes (Pontederiaceae) possess extremely low levels of genetic diversity due to severe bottleneck events and clonal reproduction. While populations elsewhere have been well studied, North American populations of E. crassipes remain understudied. We used Amplified Fragment Length Polymorphism markers to assess genetic diversity and population structure in North American E. crassipes populations. Patterns of diversity over the past fifty years were analyzed using herbarium specimens. Furthermore, we sampled populations across the Gulf Coast of the United

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12

Diop, Ousseynou. "Management of invasive aquatic weeds with emphasis on biological control in Senegal." Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1005414.

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In 1985 the Diama Dam was built near the mouth of the Senegal River to regulate flows during the rainy season and prevent the intrusion of seawater during the dry season. This created ideal conditions upstream of the dam wall for invasion by two highly invasive aquatic weeds, first by water lettuce Pistia stratiotes Linnaeus (Araceae) in 1993, and then by salvinia Salvinia molesta D.S. Mitchell (Salviniaceae) in 1999. This study was focused on the management of P. stratiotes and S. molesta. Following successes that were achieved elsewhere in the world, biological control programmes involving t

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Filizadeh, Yousef. "The management ecology of aquatic weeds which cause problems in Iranian freshwater systems." Thesis, University of Glasgow, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318119.

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14

Archibald, Sally. "Investigating the Aquatic weeds on the Westlake Wetland: Detrimental effects and management options." Bachelor's thesis, University of Cape Town, 1998. http://hdl.handle.net/11427/24395.

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The aquatic weeds on the Westlake wetland at Zandvlei (Cape Town, South Africa) were investigated in terms of their detrimental effects, and the biotic and abiotic conditions associated with their nuisance growth. Eichhornia crassipes was the most problematic of the weeds, both from a human perspective and in its effect on the system, and it appears to out-compete the initially more abundant Ceratophyllum demersum and Azolla filiculoides after disturbances such as clearing and flooding. Temperature, current strength and inter-species interactions were controlling the distribution and growth of

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15

Shaffer, Joseph D. "The effects of a six-week land-based and aquatic-based plyometric training program on power, peak torque, agility, and muscle soreness." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5161.

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Thesis (M.S.)--West Virginia University, 2007.<br>Title from document title page. Document formatted into pages; contains xi, 137 p. : ill. (some col.). Includes abstract. Includes bibliographical references.

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Hong, Jason Christopher. "Detection of Ralstonia solanacearum in irrigation ponds and semi-aquatic weeds, and its chemical treatment in water." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011874.

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17

Larson, Daniel. "Non-indigenous freshwater plants : patterns, processes and risk evaluation /." Uppsala : Dept. of Environmental Assessment, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/200715.pdf.

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18

Langa, Sílvia da Fátima. "The impact and control of waterweeds in the Southern Mozambique Basin rivers." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1001905.

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In Mozambique, establishment of aquatic weeds has been enhanced through the increased enrichment of water bodies by nutrient runoffs from human and agricultural wastes that lead to an increase in nitrate and phosphate in the water. The aquatic weeds, water hyacinth (Eichhornia crassipes), red water fern ( Azolla microphylla), water lettuce (Pistia stratiotes) and salvinia (Salvinia molesta) were found in most watercourses in Mozambique and are becoming aggressive in some watercourses, especially in the Umbeluzi and Incomati rivers. Farmers and people living along the rivers are aware of the ne

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King, Kimberly L. P. "Effects of exposure to Eurasian Milfoil (Myriophyllum spicatum) on the growth and development of Xenopus laevis and the Columbia spotted frog (Rana Lutriventris)." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/K_King_112607.pdf.

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Stafford, Martha Louise. "Biological control as an integrated control method in the management of aquatic weeds in an urban environmental and socio-political landscape : case study : Cape Town Metropolitan Area." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1013015.

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Aquatic weeds transform and degrade the ecosystems which they invade, impacting various aspects of their surroundings ranging from the community level to disrupting important processes affecting ecosystem services. All of the major aquatic weeds of South Africa are found in the Cape Town Metropolitan Area. Landowners, whether private or public, are legally obliged to manage the listed invasive species through applying environmentally acceptable methodologies. This thesis provides an overview of the strategic management options, prevention, early detection, rapid response and eradication of new

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21

Lenz, Jennifer Marie. "A Physiological Age-Grading System for Female Hydrellia pakistanae Deonier (Diptera: Ephydridae)." Thesis, University of North Texas, 2002. https://digital.library.unt.edu/ark:/67531/metadc3280/.

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Conflicting opinions about the effectiveness of H. pakistanae as a biological control agent for hydrilla prompt researchers to find a method for assessing the fly's success. Developing a physiological age-grading system for the fly using ovarian morphology to detect changes in reproductive activity is useful for evaluating reproductive status of the fly in field populations. Changes in the appearance of follicular relics in ovaries with oviposition provide a reliable method to estimate fecundity. Characteristics of follicular relics were used to develop a system with eight physiological

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Bickel, Ken (Kenneth E. ). "Assessment of Changes in Aquatic Macrophyte Occurrence Following Introduction of Triploid Grass Carp in a North Texas Reservoir." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc332827/.

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The objectives of this project were to measure changes in frequency of occurrence of submerged macrophytes over the first two growing seasons following stocking with triploid grass carp at two fish per acre and to measure differences in macrophyte biomass between areas excluded from herbivory and adjacent control sites after 16 months following establishment of exclosures. The project also seeks to measure concentrations of fluridone following the herbicide treatment, and to compare two methods of aquatic vegetation sampling.

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23

Dye, Jeremiah M. "An evaluation of two strains of Cyrtobagous salviniae Calder and Sands as natural enemies of the aquatic weeds salvinia molesta Mitchell and Salvinia minima Baker." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3331.

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The floating aquatic weeds common salvinia (Salvinia minima Baker) and giant salvinia (Salvinia molesta Mitchell) degrade aquatic systems through fast, mat forming growth. The Salvinia specialist weevil Cyrtobagous salviniae Calder and Sands has been used to reduce the severity of giant salvinia infestations and associated with reduced severity of common salvinia infestations. Genetically, morphologically and biologically distinct strains of C. salviniae exist, but their relative potential for success as biological control agents of Salvinia species has not been evaluated. This thesis (1) desc

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24

Mvandaba, Sisanda F. "The thermal physiology of Stenopelmus rufinasus and Neohydronomus affinis (Coleoptera: Curculionidae), biological control agents for the invasive alien aquatic weeds Azolla filiculoides and Pistia stratiotes respectively." Thesis, Rhodes University, 2018. http://hdl.handle.net/10962/62362.

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Water lettuce, Pistia stratiotes L. (Araceae), and red water fern, Azolla filiculoides Lam. (Azollaceae), are floating aquatic macrophytes that have become problematic invaders in numerous South African waterbodies. Two weevils, Neohydronomus affinis Hustache 1926 (Coleoptera: Curculionidae) and Stenopelmus rufinasus Gyllenhal 1936 (Coleoptera: Curculionidae), are successful biological control agents of these two species, respectively, in South Africa. However, nothing is known about the thermal physiology of these two species Therefore, the aim of this study was to investigate the thermal phy

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May, Bronwen. "Investigations into insect-induced plant responses of water hyacinth (Eichhornia crassipes (Mart.) Solms-Laub.) (Pontederiaceae)." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1018906.

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The water hyacinth (Eichhornia crassipes (Mart.) Solms-Laub (Pontederiaceae)) biological control programme makes use of tight plant-insect interactions to control the weed, by reestablishing the interactions between the plant and its natural enemies. Since the beginning of the water hyacinth biological control initiative, the impact of biological control agent herbivory on water hyacinth’s population growth and fitness have been well documented; however, very few investigations have been conducted to determine whether herbivory elicits insect-induced responses by water hyacinth. Studies were c

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Kovalenko, Katya. "Indirect effects of invasive species community effects of invasive aquatic plant control and direct and indirect effects of non-native peacock bass /." Diss., Mississippi State : Mississippi State University, 2009. http://library.msstate.edu/etd/show.asp?etd=etd-06252009-203011.

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Jones, Roy William. "The impact on biodiversity, and integrated control, of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) on the Lake Nsezi - Nseleni River system." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005397.

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Water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae), a free floating aquatic plant was discovered by C. von Martius in 1823 in Brazil. It is believed to have been introduced into South Africa, as an ornamental plant, in 1908 to the Cape Province and Natal. Since its introduction, water hyacinth has spread throughout South Africa to the detriment of all aquatic systems that it has been introduced to directly or indirectly. The weed was first positively identified on the Nseleni and Mposa rivers on the Nseleni Nature Reserve which is a protected area near Richards Bay i

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Castro, Wagner Antonio Chiba de. "Decomposição aeróbia e anaeróbia in vitro de Egeria densa Planch. e Hydrilla verticillata (L.f.) Royle de reservatórios tropicais." Universidade Federal de São Carlos, 2011. https://repositorio.ufscar.br/handle/ufscar/2036.

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Made available in DSpace on 2016-06-02T19:31:57Z (GMT). No. of bitstreams: 1 3571.pdf: 899759 bytes, checksum: 288158cbdc684b122136771cdf6c46f3 (MD5) Previous issue date: 2011-02-16<br>Universidade Federal de Minas Gerais<br>In this study it was evaluated the aerobic and anaerobic decomposition of submerged macrophytes Egeria densa Planch. and Hydrilla verticillata (L.f.) Royle, major weeds in tropical reservoirs. It was evaluated the decay of organic matter, mineralization, humification degree of the leached, fiber content, conductivity and pH of the process and activity of cellulase enzy

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Zhao, Ming. "Removal and recovery of heavy metals from synthetic solutions and electroplating effluents using yeast and the water fern Azolla filiculoides." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1004061.

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The aims of the project were twofold. The initial objective of the study, based on previous results, was to develop an economically viable methodology for immobilizing yeast cells for the treatment of heavy metal-laden waste water. The non-viable yeast cross-linked by 13% (w/v) formaldehyde/1N HNO₃ exhibited satisfactory mechanical strength and rigidity in a continuous-flow column operation. No apparent disruption of the biomass after repeated use was observed. The cost of immobilizing 1kg dry yeast pellets was estimated at less than US$I. Zn uptake capacity of FA-cross-linked pellets, on batc

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Fordham, Colin Justin. "A spatial and temporal analysis of the changes in alien macrophyte communities and a baseline assessment of the macroinvertebrates associated with Eurasian watermilfoil, Myriophyllum spicatum L. (Haloragaceae) in the Vaal River." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005455.

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The majority of South Africa’s fresh water (lotic and lentic), is eutrophic and this has resulted in water hyacinth, Eichhornia crassipes (C.Mart.) Solms. (Pontederiaceae) becoming South Africa’s most damaging aquatic macrophyte. Recently however, concerns have also been voiced over the presence of highly invasive submerged macrophyte species, such as Eurasian water-milfoil, Myriophyllum spicatum L. (Haloragaceae) in the Vaal River. Interaction studies between floating and submerged macrophytes have shown that floating macrophyte dominance restricts light penetration into the water column shad

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Bownes, Angela. "Evaluation of a plant-herbivore system in determining potential efficacy of a candidate biological control agent, cornops aquaticum for water hyacinth, eichhornia crassipes." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005373.

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Water hyacinth, Eichhornia crassipes Mart. Solms-Laubach (Pontederiaceae), a freefloating aquatic macrophyte of Neotropical origin, was introduced into South Africa as an ornamental aquarium plant in the early 1900’s. By the 1970’s it had reached pest proportions in dams and rivers around the country. Due to the sustainability, cost efficiency and low environmental risk associated with biological control, this has been a widely used method in an attempt to reduce infestations to below the threshold where they cause economic and ecological damage. To date, five arthropod and one pathogen biocon

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Marlin, Danica. "The role of the mite Orthogalumna terebrantis in the biological control programme for water hyacinth, Eichhornia crassipes, in South Africa." Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1005450.

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Water hyacinth (Eichhornia crassipes) is an aquatic macrophyte originating from the Amazon basin. Due to its beautiful appearance it has been introduced into numerous countries across the world as an ornamental pond plant. It was introduced into South Africa in the early 1900s and has since reached pest proportions in many of the country’s fresh water bodies, causing significant economic and ecological losses. It is now considered to be the worst aquatic weed in South Africa. Efforts to control the spread of the weed began in the early 1970s and there have been some successes. Biological contr

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33

Bertrin, Vincent. "Écologie et déterminisme physique des peuplements de macrophytes dans les lacs naturels peu profonds : application aux grands lacs du littoral aquitain de Carcans-Hourtin, Lacanau, Cazaux-Sanguinet et Parentis-Biscarrosse (Gironde, Landes)." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0389/document.

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Les écosystèmes littoraux lacustres, ou ceintures des lacs, ont une valeur écologique très importante. Zones de transition et d'échanges entre les écosystèmes terrestre et aquatique, les rives des lacs et leurs zones littorales sont reconnues pour abriter une forte biodiversité, dont des plantes aquatiques visibles à l'œil nu : les macrophytes. La structure spatiale, l'abondance et la composition spécifique de ces peuplements végétaux sont conditionnées par le caractère et le fonctionnement physiques des biotopes littoraux lacustres. Ce travail de thèse est dédié à l'acquisition de connaissanc

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Martin, Grant Douglas. "Drivers of macrophyte assemblages in South African freshwater systems." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1004127.

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Potentially damaging submerged invasive freshwater macrophytes have been identified in South African freshwater systems, but have received less attention than their floating counterparts. To ascertain the changes and effects that these species may have on macrophyte ecology, an understanding of the drivers of macrophyte assemblages is essential. The aims of this thesis were to investigate select abiotic and biotic factors driving introduction, establishment and spread of submerged macrophytes in South Africa. Surveys on the status of submerged plant species in South Africa were conducted to fi

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Mgobozi, Vuyokazi. "Heavy metal content absorption and medicinal potential of Egeria densa (Planch.) Casp." Thesis, University of Fort Hare, 2013. http://hdl.handle.net/10353/d1013121.

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The contamination of heavy metals in the environment is a looming concern worldwide. Egeria densa (Planch) (Submerged aquatic plant) from two ponds: Site A with co-ordinates (32º 48’22.04”S; 26°48’58.79” E) and Site B with co-ordinates (32°48’33.25”S; 26°48’33.25”S) in Alice (Eastern Cape) was evaluated for its ability to absorb heavy metals, phytochemical constituents, antimicrobial activity and ultra-structure using standard analytic procedures. Cadmium (Cd), copper (Cu), iron (Fe), lead (Pb), manganese (Mn), and zinc (Zn) were measured in water, sediments and plant. The concentrations of th

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Kwong, Raelene M., Linda M. Broadhurst, Brian R. Keener, Julie Coetzee, Nunzio Knerr, and Grant D. Martin. "Genetic analysis of native and introduced populations of the aquatic weed Sagittaria platyphylla – implications for biological control in Australia and South Africa." 2017. http://hdl.handle.net/10962/76991.

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Sagittaria platyphylla (Engelm.) J.G. Sm. (Alismataceae) is an emergent aquatic plant native to southern USA. Imported into Australia and South Africa as an ornamental and aquarium plant, the species is now a serious invader of shallow freshwater wetlands, slow-flowing rivers, irrigation channels, drains and along the margins of lakes and reservoirs. As a first step towards initiating a classical biological control program, a population genetic study was conducted to determine the prospects of finding compatible biological control agents and to refine the search for natural enemies to source p

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Diop, Ousseynou. "Management of invasive aquatic weeds with emphasis on biological control in Senegal /." 2006. http://eprints.ru.ac.za/877/.

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Newete, Solomon Wakshim. "Hyperspectral remote sensing to detect biotic and abiotic stress in water hyacinth, (Eichhornia crassipes) (pontederiaceae)." Thesis, 2014. http://hdl.handle.net/10539/14997.

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A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Doctor of Philosophy School of Animal, Plant and Environmental Sciences, Johannesburg, 2014<br>Water hyacinth (Eichhornia crassipes) is one of the most notorious aquatic weeds in the world. Its management, despite the release of seven biocontrol agents since 1974, remains a problem in South Africa. This is often attributed to the high level of eutrophication. However, information on the effect of heavy metals or AMD on Neochetina eichhorniae and N.

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Jadhav, Ashwini Mohan. "Integrated control of water hyacinth using a retardant dose of glyphosate herbicide." Thesis, 2012. http://hdl.handle.net/10539/11338.

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Ph.D, Faculty of Science, University of the Witwatersrand, 2011<br>Abstract Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) (water hyacinth), a neotropic noxious weed of South American origin, is counted among the “big five” aquatic weeds in South Africa. The weed causes dramatic ecological and economic losses in infested areas. Its control is facilitated by the release of biocontrol agents, mainly Neochetina eichhorniae (Warner) and Neochetina bruchi Hustache (Coleoptera: Curculionidae). Control efforts via biocontrol are hampered, mainly by the climate incompatibility of

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Du, Plessis Barend Jakobus. "The application of triploid grass carp, as biological control agent for the over-abundant growth of aquatic weeds in irrigation canal systems." Thesis, 2008. http://hdl.handle.net/10210/1018.

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The overabundant proliferation of aquatic weeds in South African water conveyance systems cause a series of operational problems. Filamentous algae, such as Cladophora glomerata and pondweeds impede flow and reduce the capacity of irrigation canals to a significant extent. In worst case scenarios, irrigation scheme managers are faced with situations where they are unable to deliver water at the downstream ends of canal systems. This situation also contributes to water losses, crop losses and structural damage to concrete-lined canals. This dissertation is the product of a research project fund

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Hill, M. P., and Julie Coetzee. "The biological control of aquatic weeds in South Africa: current status and future challenges." 2017. http://hdl.handle.net/10962/59909.

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Aquatic ecosystems in South Africa have been prone to invasion by introduced macrophytes since the late 1800s, when water hyacinth, Eichhornia crassipes (Mart.) Solms-Laub. (Pontederiaceae), was first recorded as naturalised in KwaZulu-Natal (Cilliers 1991). Several other species of freshwater aquatic plants, all notorious weeds in other parts of the world, have also become invasive in many of the rivers, man-made impoundments, lakes and wetlands of South Africa (Hill 2003). These are Pistia stratiotes L. (Araceae) (water lettuce); Salvinia molesta D.S. Mitch. (Salviniaceae) (salvinia); Myriop

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Jones, Roy William. "The impact on biodiversity, and integrated control, of water hyacinth, Eichhornia crassipes (Martius) Solms-Laubach (Pontederiaceae) on the Lake Nsezi - Nseleni River system /." 2008. http://eprints.ru.ac.za/1600/.

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Meyer, Machiel Daniel Bester. "Invloed van die plantdoders Dikwat en Terbutrin op die groei van Euglena gracilis Klebs." Thesis, 2014. http://hdl.handle.net/10210/10782.

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Oberholzer, Izak Gerhardus. "The effect of nutrient rich water on the biological control of water hyacinth." Diss., 2002. http://hdl.handle.net/2263/28536.

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Please read the abstract on p1 of the document 00dissertation<br>Dissertation (M Inst Agrar (Sustainable Insect Management))--University of Pretoria, 2007.<br>Zoology and Entomology<br>M Inst Agrar<br>unrestricted

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"Die gebruik van die Sjinese Graskarp (Tenopharyngodon idella (Val.) in die beheer van die onderwatermakrofiet Potamogeton pectinatus L. in Germistonmeer." Thesis, 2015. http://hdl.handle.net/10210/14585.

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Bokotomba, Ndongo Fyfy. "The effect of temperature on the feeding and development of Neochetina eichhorniae weevil larvae on water hyacinth (Eichhornia crassipes)." Thesis, 2017. http://hdl.handle.net/10539/23564.

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A dissertation submitted to the Faculty of Science, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science. Johannesburg, March 2017.<br>Water hyacinth (Eichhornia crassipes) is an example of an alien invasive plant, threatening ecosystems around the world. Taking into consideration all the negative impacts caused by the proliferation of water hyacinth, many control measures have been implemented to manage this weed. These include mechanical control, chemical control and biological control. But in recent years, the focus has shifted towar

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Bownes, Angela. "Evaluation of a plant-herbivore system in determining potential efficacy of a candidate biological control agent, cornops aquaticum for water hyacinth, eichhornia crassipes /." 2008. http://eprints.ru.ac.za/1567/.

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Rwizi, Lameck. "Evaluating the effects of invasive alien plants on water availability and usability of lake water in Gauteng Province." Diss., 2014. http://hdl.handle.net/10500/15419.

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The invasion of ecosystems by alien species is a growing threat to the delivery of ecosystem services. This study explored the spatial distribution of water hyacinth in the Benoni Lakes and made analysis of its impact on water availability and usability in order to understand the evolution and its propagation rates. The study used satellite imagery for lake level modelling using Remote Sensing and Geographical Information Systems for calculations of area covered by weeds in each lake from 2002 to 2012.The modelling approach illustrates the potential usefulness in projecting invasive plan

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