FIRST REPORT OF THE ESTABLISHMENT OF CYPHOCLEONUS ACHATES (FAHRAEUS) (COLEOPTERA: CURCULIONIDAE) ON SPOTTED KNAPWEED, CENTAURE A MACULOSA LAMARCK, IN THE UNITED STATES
Cyphocleonus achates (Fahaeus) is a Eurasian, root-feeding weevil introduced into North America for the biological control of spotted knapweed, Centaurea maculosa Lamarck. Stinson et al. (1994) reported that C. achates is one of the most damaging root-feeding insects on knapweed in Eurasia and should be a valuable addition to the biocontrol effort in North America. The biology, host specificity, and potential impact of the weevil were described by Stinson et al. (1994). Larvae mine into the root cortex where they induce formation of a conspicuous root gall. Feeding by older larvae causes much damage, especially to small plants or plants containing several larvae. The weevil overwinters as a larva in the root and emerges as an adult from mid-July to October. Adult weevils are large (14 mm long) and flightless, and feed on knapweed foliage. The weevil has one generation per year.