The Status of Biological Control of the Weed Hypericum Perforatum in British Columbia

Biological control attempts against the weed Hypericum perforatum L. in the interior of British Columbia are summarized. Three of the insects introduced, Zeuxidiplosis giardi Kieff., Agrilus hyperici (Cr.), and Chrysolina varians (Schall.), did not survive, and reasons for their failure are discussed. Two beetles, C. hyperici (Forst.) and C. quadrigemina (Suff.), are established and their population build-up in several areas is followed over a period of 15 years. The beetles reach their optimum effectiveness in different moisture zones but neither species is effective at the arid end of the H. perforatum range. A moth, Anaitis plagiata L., was released in this zone in 1967.