This disease is caused by any of a number of different fungi, also known as water molds, that persist indefinitely in the soil. They thrive in waterlogged, heavy soil. Some of these fungi attack the plant stems at the soil level, while others attack the roots. Infection causes the roots and stems to decay. This results in wilting, then yellowing leaves, and eventually the death of the plant. These fungi are generally spread by infested soil and transplants, contaminated equipment, and splashing or running water. Many of these organisms also cause damping-off of seedlings. For more information about damping-off, see Damping-Off.
Allow the soil around the plant to dry out. (For more information on this technique, see Water Molds.) Remove and discard severely infected plants. Avoid future root rot problems by planting in well-drained soil. (For information on improving soil drainage, see Soil Types, Soil Structure, and Groundwater.)
Plant Care for Centaurea