Kendall, Deborah M. 1996. Biocontrol Pest Management for Thistles in Wind Cave National Park. Annual and Semiannual Reports; Proj. No.: WICA-R92-0200; Coop Agreement:CA 1268-1-9016; Work Order: FLC-5, FLC-8, FLC-10, FLC-14, FLC-19; 1992-1996.

Abstract

Biological control of Canada thistle, Cirsium arvense L. in Wind Cave National Park focused on the release and subsequent monitoring of the following insects: the thistle gall fly, Urophora cardui; and the seedhead weevil, Larunius planus. Two additional insect species were also monitored, but not released; the painted lady butterfly, Vanessa cardui, a migratory herbivore of thistles and Rhincoyllus conicus, a seedhead weevil that has entered Wind Cave National Park from surrounding areas. Assessment of damage by these biocontrol agents on native Cirsuim species was also conducted. Results indicated that all insect biocontrol agents were established in three study sites in Wind Cave National Park. Seedhead analysis also indicated no colonization of native thistles by biocontrol species.