Damping-off
plants that are in a sub-optimal condition or suffer from stress, caused for example by too much water, too high or low temperatures or sudden fluctuations [...] older plants, the leaves lose their turgor or the leaf tips turn yellow, for example in flower bulbs. At first, the plants recover during the night, but [...] brown. A typical symptom of a Pythium infection is the easy stripping of the skin from the root cortex with a finger nail. Life cycle and appearance of Damping-off