Bitter Rot

bitter rot, a fungal disease of ripe grapes that is active in warm, humid conditions. It is found only on damaged and almost senescent tissues, but the bitter fruit flavour can be detected in the finished wine. The cause is the fungus Greeneria uvicola and the disease is widespread in the eastern United States, Asia, Australia, and South Africa but not in France or Germany. The disease is easily controlled by most fungicides.