Cirsium arvense (L.) Scop. (Canada thistle) is a persistent perennial pasture weed in Eastern Canada. Single control measures such as cultural, chemical, and biological methods are not effective in long term reduction of the weed population. The objectives of this research project were to evaluate the efficacy of various traditional control methods and to attempt to integrate them. / The effectiveness of Urophora cardui L. as a biological control agent is limited due to a lack of synchrony between the agent and the weed. This can be improved through integration with herbicides or mowing in time or space. Other biological control agents such as Orellia ruficauda Fab., Cassida rubiginosa Muell., and Puccinia punctiformis (Str.) Rhol. resulted in limited suppression of the weed population. Mowing was not effective in sustaining weed reductions for longer than one year. Application of clopyralid or 2,4-D/dicamba effectively reduced the weed population. The application of 3.37 kg a.i. ha$ sp{-1}$ 2,4-D/dicamba or 0.3 kg a.i. ha$ sp{-1}$ clopyralid with the spring and summer mowings were the most effective mowing/herbicide combinations over the two-year period.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.61205 |
| Date | January 1991 |
| Creators | Diamond, Juanita F. (Juanita Florence) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Plant Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001276598, proquestno: AAIMM74890, Theses scanned by UMI/ProQuest. |
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