Lygus Hahn (Hemiptera: Miridae) are serious pests of economically important field, fruit, vegetable, and greenhouse crops in Canada. The release of European Peristenus Förster (Hymenoptera: Braconidae) in the USA has resulted in significant suppression of this pest and has renewed interest in the release of European Peristenus spp. in Canada. Prior to the release of exotic Peristenus spp., ecological host range studies need to be conducted to define their habitat and host associations. <p>These associations can be difficult to study using conventional methods. Morphological similarity of related parasitoids prevents species-level identification by dissection. Host rearing is time-consuming and can result in high levels of host and parasitoid mortality. To facilitate identification of immature Peristenus spp. in their hosts, a multiplex PCR assay was developed. This assay provided a specific and sensitive tool to screen individual insects for three parasitoid species simultaneously. <p>To validate the utility of the multiplex PCR assay in ecological host range studies, parasitism and parasitoid species composition obtained using conventional and molecular techniques were compared. Molecular methods compared favorably with conventional methods; however, more complete species composition information was available with the multiplex assay. To improve the quality of risk assessment studies and extract the most accurate ecological host range data, molecular methods were used to evaluate host-parasitoid associations in mirid populations collected in two ecoregions. Several new host-parasitoid associations were recorded for <i>P. digoneutis</i> and <i>P. relictus</i>, but parasitism of non-target mirids was low. <p>Parasitism of the target host collected from different plant species was evaluated to help clarify Peristenus host-plant associations. Despite the investigation of three different host plant species, no difference was observed in the parasitism level or parasitoid species composition in <i>L. rugulipennis</i>.
The post-release utility of the multiplex assay was investigated in Canada, where Lygus parasitoids may have dispersed following release in the USA. To confirm establishment, samples were analyzed using the multiplex PCR assay, and P. digoneutis was detected for the first time in southern Ontario.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-04132007-115125 |
| Date | 24 April 2007 |
| Creators | Gariepy, Tara Dawne |
| Contributors | Kuhlmann, Ulrich, Gillott, Cedric, Erlandson, Martin, Davis, Arthur R., Messier, François |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-04132007-115125/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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