The beetle was introduced in 1943 as an attempt to control the weed, and is a classic case of successful biological control (Huffaker, 1959; Van Driesche et al., 2010).
J. K. Holloway of the USDA and H. S. … The success of the chrysomelid beetles, Chrysolina hyperici (Forster) and C. quadrigemina (Suffrian), used widely for biological control of St John's wort (Hypericum perforatum) seems to depend on the synchronization of their phenologies with climate. Montana biological Weed Control Coordination Project (MTBCP) is a grassroots effort created to provide the leadership, coordination, and education necessary to enable land managers across Montana to successfully incorporate biological weed control into their noxious weed management programs. The U.K. fauna includes 19 species, some of which are recent introductions, and it seems likely that more will be recorded. In 1944 the introduction of several insect species from Australia was made to California for specificity testing and release during 1945-46 for the biological control of St. Johnswort, which became known as Klamath weed. For example, the leaf beetle, Chrysolina hyperici (Förster) was transferred from Australia to New Zealand in 1943 for the biological control of St. Johnswort. In addition to directly consuming the plant, the beetle also acts as a vector for the pathenogenic fungus Colletotrichum gloeosporioides , which may additionally help to control the exotic H. perforatum ( Morrison, Reekie & Jensen, 1998 ). They are among the largest and most striking of our leaf beetles and although some seem to have declined in recent decades there are several common species that …