Chrysolina is a large genus of leaf beetles in the subfamily Chrysomelinae. The species Chrysolina cerealis and C. graminis are protected in the United Kingdom. All species of Chrysolina are phytophagous, feeding on specific food plants, and some of them have been used for biological control of weeds. To control Hypericum perforatum (St John's wort), C. hyperici was successfully naturalized in Australia in the 1930s and several species, especially C. quadrigemina, were introduced to California in the late 1940s.