sclerotinia diseases occur as dry cankers, rots, blights, and damping-off on succulent plants throughout the world in the field, in transit, and in storage. They are especially significant on vegetables such as cabbage, lettuce, and beans. If dry conditions prevail after infection, which requires relative humidity in excess of 90%, then only dry brown cankers develop. If humid conditions continue after infection, the entire plant may be covered with a weft of white mycelium in which large black sclerotia are formed (Fig. 33-1). The fungus thrives under cool, moist conditions.