Host plant oviposition preference ofCeratapion basicorne(Coleoptera: Apionidae), a potential biological control agent of yellow starthistle

Ceratapion basicorne is a weevil native to Europe and western Asia that is being evaluated as a prospective classical biological control agent of Centaurea solstitialis (yellow starthistle) in the United States. Choice oviposition experiments were conducted under laboratory conditions to help assess host-plant specificity of the insect. Mean oviposition rates were highest on C. solstitialis (66% of eggs, on a per replicate basis) followed by Centaurea cyanus (bachelor's button 22%), Centaurea melitensis (6%), Centaurea americana (1%), Saussurea americana (3%) and Carthamus tinctorius (safflower 2%). Adult feeding damage followed a similar pattern; however, there was less oviposition relative to the amount of adult feeding on each of the non-target species than on the target host plant, C. solstitialis. Thirteen safflower varieties were tested, and oviposition occurred on eight of them, at low rates. Adult feeding occurred on all safflower varieties tested, although at rates much lower than on yel...