Damping-off

   Fungal organisms which cause damping-off include Pythium spp., Rhizoctonia solani, Thielaviopsis basicola, Fusarium equiseti, and others. Affected seedlings fail to emerge or collapse shortly after emergence. Emerged seedlings affected by Pythium turn a light green color and the cotyledons collapse. Water soaked lesions also appear on the seedlings at the soil level. Lesions caused by Thielaviopsis are grey to reddish but turn to a coal black color. A red to brown rot is more characteristic in infections caused by Fusarium. Humid conditions caused by close planting, poor drainage, or by rainfall are conducive for damping-off. Control for damping-off in the greenhouse include proper soil sterilization and strict sanitation practices. In the field cultural practices which improve drainage and wider planting distances are recommended. High quality seed is recommended but resistance to damping-off is not available.