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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Identification and Syntheses of Semiochemicals Affecting Mnesampela privata and Trioza apicalis

Nilsson, Anna January 2009 (has links)
<p>The Autumn gum moth, <em>Mnesampela privata </em>(Lepidoptera: Geometridae) is an endemic Australian moth whose larvae feed upon species of <em>Eucalyptus.</em> The moths favorite host plants are <em>E. globulus </em>and<em> E. nitens</em> which are the most important species used in commercial plantations of the Australian pulpwood industry. The autumn gum moth has become one of the most significant outbreak insects of eucalyptus plantations throughout Australia. As a consequence great financial losses to the forest industry occur. Today insecticides such as pyrethroids are used for control of eucalyptus defoliators as <em>M. privata</em>.</p><p>The carrot psyllid, <em>Trioza apicalis </em>(Homoptera: Psylloidea), is one of the major pests of carrot (<em>Daucus carota</em>) in northern Europe. The psyllid causes curling of the carrot leafs and reduction of plant growth. Today the carrot crops are protected with the pyrethroid insecticide cypermethrin, which is toxic to aquatic organisms and is, from 2010, prohibited for use in Sweden by the Swedish Chemicals Inspectorate.</p><p>An alternative to insecticides is to protect the seedlings with semiochemicals, a chemical substance or mixture of them that carries a message. This thesis describes the identification and the syntheses of semiochemicals from the above mentioned insect species.</p><p>From analysis of abdominal tip extracts of <em>M. privata</em> females from Tasmania a blend of (3<em>Z</em>,6<em>Z</em>,9<em>Z</em>)-3,6,9-nonadecatriene and (3<em>Z,6Z,9Z</em>)-3,6,9-heneicosatriene was identified as the sex pheromone of this species. The identification of the C<sub>19</sub>- and C<sub>21</sub>-trienes was confirmed by synthesis.</p><p>In the analysis of carrot leaf extracts we found a compound, α-<em>cis</em>-bergamotene, that induces antennal response in the carrot psyllid. This is just the beginning of the studies of trying to manipulate this psyllid with semiochemicals instead of insecticides.</p>
2

Identification and Syntheses of Semiochemicals Affecting Mnesampela privata and Trioza apicalis

Nilsson, Anna January 2009 (has links)
The Autumn gum moth, Mnesampela privata (Lepidoptera: Geometridae) is an endemic Australian moth whose larvae feed upon species of Eucalyptus. The moths favorite host plants are E. globulus and E. nitens which are the most important species used in commercial plantations of the Australian pulpwood industry. The autumn gum moth has become one of the most significant outbreak insects of eucalyptus plantations throughout Australia. As a consequence great financial losses to the forest industry occur. Today insecticides such as pyrethroids are used for control of eucalyptus defoliators as M. privata. The carrot psyllid, Trioza apicalis (Homoptera: Psylloidea), is one of the major pests of carrot (Daucus carota) in northern Europe. The psyllid causes curling of the carrot leafs and reduction of plant growth. Today the carrot crops are protected with the pyrethroid insecticide cypermethrin, which is toxic to aquatic organisms and is, from 2010, prohibited for use in Sweden by the Swedish Chemicals Inspectorate. An alternative to insecticides is to protect the seedlings with semiochemicals, a chemical substance or mixture of them that carries a message. This thesis describes the identification and the syntheses of semiochemicals from the above mentioned insect species. From analysis of abdominal tip extracts of M. privata females from Tasmania a blend of (3Z,6Z,9Z)-3,6,9-nonadecatriene and (3Z,6Z,9Z)-3,6,9-heneicosatriene was identified as the sex pheromone of this species. The identification of the C19- and C21-trienes was confirmed by synthesis. In the analysis of carrot leaf extracts we found a compound, α-cis-bergamotene, that induces antennal response in the carrot psyllid. This is just the beginning of the studies of trying to manipulate this psyllid with semiochemicals instead of insecticides.
3

Využití komprehensivní dvoudimenzionální plynové chromatografie s hmotnostně spektrometrickou detekcí pro metabolomickou analýzu houby Gloeophyllum trabeum / Use of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection for metabolomic analysis of Gloeophyllum trabeum fungus

Kuchler, Ondřej January 2019 (has links)
Fungus Gloeophyllum trabeum (Agaricomytes: Gloeophyllates) is a brown rot wood-decay fungus which produces a vast spectrum of volatile secondary metabolites. Scientific publications state, that one of the metabolites produced by G. trabeum, can be the substance (3Z,6Z,8E)-dodecatrien-1-ol. This chemical substance is also the main component of trail-following pheromone of Rhinotermitidae termite family. In this diploma thesis, I was trying to verify whether various species of G. trabeum are in fact capable of producing the substance (3Z,6Z,8E)-dodecatrien-1-ol. I was also focusing on the effects of saccharides, present in nutrient solutions, on quantitative and qualitative change in composition of volatile secondary metabolites produced by G. trabeum. The saccharides I used for my research were - maltose, fructose, sucrose, xylose, and mannose. The analysis was made by using comprehensive two-dimensional gas chromatography separation technique with time-of-flight mass spectrometric detection (GC×GC-TOFMS). During my research I discovered that one of obtained species of G. trabeum can produce substance (3Z,6Z,8E)-dodecatrien-1-ol, but only under specific conditions. It is produced when cultivating on Petri dishes on agar - cellulose growth media. The measurement was further validated by...

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