Canada thistle biological control agents on two South Dakota wildlife refuges

Catherine C. Reed, Diane L. Larson, Jennifer L. Larson

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)47-52
Number of pages6
JournalNatural Areas Journal
Issue number1
StatePublished - Jan 2006


  • Biocontrol
  • Canada thistle
  • Ceutorhynchus litura
  • Cirsium arvense
  • Rhinocyllus conicus


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