<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 C₁₉- and C₂₁-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>

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.