Life History and Host Range of Ceratapion basicorne (Coleoptera: Apionidae) with Notes on Other Weevil Associates (Apioninae) of Yellow Starthistle in Italy and Greece

Abstract

Species of Ceratapion weevils associated with yellow starthistle, Centaurea solstitialis L., in Italy and Greece were identified. The life history and laboratory host specificity of the most abundant species, Ceratapion basicorne (Illiger), were studied from 1983 to 1985 to determine the species potential as a biological control agent for yellow starthistle. This insect is probably univoltine and overwinters as an adult. Good synchronization was observed between oviposition and larval development of C. basicorne and the occurrence of rosettes and bolting plants of yellow starthistle. In the field, eggs appeared in rosettes from late March to about mid-May; larvae in roots, crowns, and basal stems during April, May, and June; and pupae in larval feeding galleries during May and June. Teneral adults first appeared in late May. An egg parasitoid, Anaphes (Patasson) sp. (Hymenoptera: Mymaridae), and a prepupal and pupal ectoparasitoid, Trichomalus sp. (Hymenoptera: Pteromalidae) of C. basicorne were discovered. Total developmental time in the laboratory (22–30°C) was 34–37 d. In laboratory host specificity tests, adults fed and oviposited on safflower in the absence of yellow starthistle, and the host range of the larvae included yellow starthistle, two other weedy thistles, and safflower.