AbstractScentless chamomile, Matricaria perforata Mérat [= Matricaria maritima var. agrestis (Knaf) Wilmot], is a widely distributed, rapidly spreading and aggressive weed, especially in the three Prairie Provinces. The seed-feeding weevil, Apion hookeri Kirby (Coleoptera: Curculionidae), is widespread and common in its native range in the Palaearctic. It occurs in such differing climates as the Mediterranean in northern Africa and the boreal climate of western Siberia. The weevil was screened for its host specificity. In the laboratory, females oviposited into the flowers of species in six genera of the tribe Anthemideae, and one species in the tribe Astereae. However, the larvae developed only in Matricaria species, and one adult emerged from stinking mayweed, Anthemis cotula L. In a choice test, ovipositing A. hookeri preferred scentless chamomile 93:1 over stinking mayweed. These results confirm host records in the European literature. It is concluded that A. hookeri is a host-specific and promising agent for the biological control of scentless chamomile.
