by: Jorge Cervantes
Damping-off attacks rooting cuttings at the soil line if present in growing medium. As the fungi invade stem tissue it loses girth at the soil line, weakens, then discolors with a brown watery soft rot, and finally fluid circulation is cut, killing the seedling or cutting. It prevents newly sprouted seeds from emerging, and attacks seedlings causing them to rot at the soil line, yellows foliage and rots older plants at soil line.
Pythium is often the cause of damping-off. Cleanliness is the best way to avoid damping-off.
Damping-off is caused by different fungal species, including Botrytis, Pythium, and Fusarium are present in the air, growing medium plant or seed. This disease breeds in wet, poorly aerated over-watered growing mediums, humid conditions and attacks weak plants.
This marijuana clone rotted in the soil due to damping-off disease.
Coat seeds with protective dust for insurance. Seed disinfection is used to kill organisms of anthracnose and other species diseases carried on seed. Damping off organisms are in the soil, not on the seed. The coating is intended to kill or inhibit fungi in the soil immediately surrounding the seed and so provide temporary protection during germination.
Cuttings are less susceptible to damping-off and love a humidity tent to promote rooting. Keep germination temperatures between 70-85°F (21-29°C). Be very attentive to soil moisture and overall clone health.
Control damping-off biologically in seeds with Polygangron® (Pythiumoligandrum) granules to soil and seed. Bak Pak® or Intercept® are applied to the soil and Deny® or Dagger®–forms of the bacterium Burkholderiacepacia–are put on the seeds. Epic®, Kodiac®, Quantum 4000®, Rhizo-Plus®, System 3®, and Seranade® also suppress many causes of damping- off.
Chemical controls include dusting with Captan®. Avoid benomyl fungicide soil drench because it kills beneficial organisms.