St. John’s wort (Hypericum perforatum), a member of the Guttiferae family (syn. Hypericaceae, Clusiaceae), has been used for its medical properties throughout the ages. It is currently recommended in plant therapy for its antiviral, vulnerary and antidepressive properties, and this ability to fight depression is naturally attracting the pharmaceutical industry’s interest. H. perforatum based formulations are used for light or mild depression.

In Switzerland, the H. perforatum fields were attacked by the Colletotrichum gloeosporioides fungus, causing anthracnose starting in 1995. Most of the 20 hectares of H. perforatum fields planted in this country are currently managed with a biological specification. Anthracnose can destroy those perennial cultures from the first year, mainly in heavy soil and damp regions. Since the specification does not allow the use of fungicides, those cultures usually are irretrievably lost. Hollow lesions circling the stems are noted in infected plants. (Mediplant, Conthey)