| Abstract: | We monitored populations of Canada thistle biocontrol agents Cassida rubiginosa, Ceutorhynchus litura, Larinus (= Hadroplantus) planus, Urophora cardui, Orellia (= Terellia) ruficauda, and Rhinocyllus conicus on Canada thistle (Cirsium arvense) at two national wildlife refuges in South Dakota from 1999 through 2003. C. litura, U. cardui, O. ruficauda, and R. conicus were present on both refuges. Agent populations were low except for C. litura, which was present in up to 90% of stems in some plots. C. litura infestation did not reduce thistle flowering, stem length, or over-winter survival. There was no change in thistle stem numbers over the study period and no difference in stem numbers in areas of high C. litura populations compared to areas of low C. litura populations. Our results suggest that insect biological control agents are inadequate for reduction of Canada thistle in southern South Dakota. |
| Genre: | Article |
| ProdID: | 70031152 |
| Citation Author: | Reed, C. C.; Larson, D. L.; Larson, J. L. |
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| Citation End Page: | 52 |
| Citation Issue: | 1 |
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| Citation Language: | English |
| Citation Larger Work Title: | Natural Areas Journal |
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| Citation Number Of Pages: | 6 |
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| Citation Publisher: | Natural Areas Association |
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| Citation Search Results Text: | Canada thistle biological control agents on two South Dakota wildlife refuges; 2006; Article; Journal; Natural Areas Journal; Reed, C. C.; Larson, D. L.; Larson, J. L. |
| Citation Start Page: | 47 |
| Citation Volume: | 26 |
| Citation Year: | 2006 |
| Type: | citation/reference |
| Text: | Canada thistle biological control agents on two South Dakota wildlife refuges; 2006; Article; Journal; Natural Areas Journal; Reed, C. C.; Larson, D. L.; Larson, J. L. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.3375/0885-8608(2006)26[47:CTBCAO]2.0.CO;2 |
| Date Other: | Sun, 1 Jan 2006 00:00 -0600 |
| Publisher: | Natural Areas Association |
