BIOCONTROL OF CANADA THISTLE (CIRSIUM ARVENSE): RELEASES AND EFFECTIVENESS OF CEUTORHYNCHUS LITURA (COLEOPTERA: CURCULIONIDAE) IN CANADA

Publisher Website
Google Scholar
Abstract
Ceutorhynchus litura (F.) (Coleoptera: Curculionidae) is established since 1967 in Ontario, and is increasing slowly on nine release sites in five provinces. The weevil is not a good control agent because its reproductive capacity does not compensate for losses inflicted by cultivation and the stress resulting from larval mining is so light that it produces no noticeable reduction in the vigour of Canada thistle (Cirsium arvense (L.) Scop.). In contrast to earlier findings, it is doubtful that C. litura aids in the spread of the rust Puccinia punctiformis (Str.) Rohl. Further stress factors from other insects or pathogens are needed to control this vigorous weed.