Hypericum-perforatum
Guides
Agrilus hyperici
St. John's wort root borer
Agrilus hyperici is a jewel beetle (family Buprestidae) used as a biological control agent against the invasive weed Hypericum perforatum (common St. John's wort). Native to Europe, it was first introduced to the United States in 1950 and is now established in the northwestern United States and Australia. The species is notable for its root-boring larval stage that typically kills host plants.
Chrysolina hyperici
Saint John's Wort Beetle, St. Johnswort Beetle, Klamathweed Beetle
Chrysolina hyperici is a leaf-feeding chrysomelid beetle native to Europe and Asia, widely introduced as a biological control agent for invasive St. John's wort (Hypericum perforatum). The species has been established in North America, Australia, and other regions where its host plant has become problematic. Populations are often transient and alone do not provide sustained weed suppression, though the beetle can mechanically vector a host-specific fungal pathogen that enhances control effectiveness.