An Annotated List of Insects Associated With Canada Thistle (Cirsium Arvense) in Canada

As part of the biological control of Canada thistle,Cirsium arvense(L.) Scop., in Canada, a survey of the insect fauna showed 80 identified or apparent phytophagous species representing 24 families and seven orders and 47 species of visitors, insect parasites, and predators representing 28 families and six orders. Thirty-eight per cent of the phytophagous insects attack economic plants. Three species,Altica carduorum,Ceutorhynchus litura, andUrophora cardui, are specific toC.arvenseand were introduced as control agents.