Spotted Knapweed Root Weevil (Cyphocleonus achates)
Introduced from Austria, Hungary, and Romania in the USA in 1988. This weevil prefers hot, dry sites with loose, well-drained, coarse soils.
Spotted Knapweed Flower Weevil (Larinus spp)
Introduced from Greece and Romania and originally released in the USA in 1991. This weevil typically prefers hot, dry sites with dense stands of knapweed in well-drained, coarse soils.