Pythium is a group of water molds in the oomycete genus Pythium that cause root rot, damping-off, and stem collapse in many garden and houseplants. Although often called fungi, oomycetes are a separate group of fungus-like organisms that thrive in wet, poorly aerated conditions.
In seedlings, Pythium commonly causes damping-off, where stems thin at the soil line and young plants topple. In established plants it damages roots, reducing water uptake and causing wilting, yellowing, stunting, and decline even when the growing medium is moist.
Outbreaks are favored by overwatering, contaminated tools or media, crowded propagation trays, and stagnant water systems. Management relies on sanitation, well-drained media, controlled irrigation, and removal of infected plants.
See Also
