Damping Off
|
Damping Off  Damping-off generally refers to sudden plant death in the seedling stage due to the attack of fungi. These fungi are soilborne and are stimulated to grow and infect the seed or seedling by nutrients released from a germinating seed. However, seedlings may be injured or killed by something other than fungi, for example, toxic materials in the soil, excess or deficient soil moisture, seed defects, temperature extremes, toxic gases in the air, etc. A correct diagnosis is the key to effective control measures. Susceptible Plants- Seeds, Seedlings, cuttings, roots, and vegetable parts at or below soil level, such as carrots or celery. Symptoms- When seeds are planted in infested soils, damping-off fungi may attack them at any stage. The damping-off fungi may attack the seed prior to germination, or they may attack after the seed has germinated but before the seedling has emerged above the soil line. Infected seed becomes soft and mushy turning a brown to black color, and it eventually disintegrates. Seeds that have germinated and become infected develop water-soaked spots that enlarge and turn brown. The infected tissue collapses, resulting in death of the seedling. Penetration and death of seeds before they emerge is termed pre emergence damping-off. Seedlings that have emerged are usually attacked at or below the soil line. The organism can easily penetrate the young soft stem tissue.
The infected stem portion becomes discolored and begins to shrink. As this occurs, the supportive strength of the stem's invaded portion is lost, and the seedling topples over. The fungi continue to invade the remaining portion of the seedling, resulting in death.
This phase of the disease is termed post emergence damping-off. Older established plants also can be attacked by damping-off fungi. Usually the new developing rootlets are infected, resulting in root rot. Infected plants show symptoms of wilting and poor growth.used to better control the environment when starting seeds indoors. Sow when soil has warmed well in the spring. See also Phytophthora root and stem rot to control damping off disorder. . Biological Fungicide Control - PlantShield® HC - Biological Fungicide - Foliar and Root Fungicide OMRI Listed, approved under the Washington State Department of Agriculture's Organic Food Program and complies with the USDA National Organic Program. Prevents Damping Off and other common wilts and rots! PlantShield® HC Biological Fungicide is a formulation of the beneficial fungus Trichoderma harzianum strain T-22.
It is used for the preventative control of many root infecting pathogens such as Pythium, Rhizoctonia, Fusarium, Cylindrocladium and Thielaviopsis. It can be applied in powder form to seeds, transplants or cuttings or as a drench.
|
|
