This disease is a rotting of the roots and the base of the stem so that the seedling falls over and dies. Damping-off is caused by a number of different fungi which live in the soil and may attack seedlings of almost any crop. The disease is favored by high soil moisture and cool temperatures. To avoid damping-off, start seedlings in pasteurized soil or use soilless potting mix, give them only enough water to keep the plants growing normally, and ventilate the growing space during the day. Once plants are beyond the seedling stage, they are not susceptible to damping-off.
Symptoms appear as wilting and a slow or rapid collapse of the plant.
The roots can appear brown and water-soaked instead of white. A water-soaked lesion can often appear at the base of the stem. Control can be achieved by using sterile potting media, clean pots, and fungicide-treated seed. Affected transplants should be rogued out and discarded. Control in the field can be achieved by using a two-year rotation with nonsusceptible plants, such as corn, to prevent the buildup of pathogenic organisms.