Damping-off Fungus

Definition - What does Damping-off Fungus mean?

Damping-off fungus is a disease that attacks seedlings and cuttings. It is caused by several soil-borne types of fungus-like organisms and fungi such as phytophthora, pythium, and rhizoctonia and fusarium.

The disease is a prevalent problem among seedlings grown indoors or within the confines of a greenhouse.

Afflicted seedlings often fail to emerge from the soil or they decay and collapse shortly after emerging. Growers frequently notice a pile of white fungus around the sick seedling and on the soil’s surface.

Many growers refer to damping-off fungus simply as 'damping off'.

MaximumYield explains Damping-off Fungus

The damping-off fungus is common in locations with high humidity, poor air circulation, and when the seeds are not adequately spaced when sown. Germinated seedlings that aren't properly 'hardened off' before being transplanted outdoors in the early spring are also more susceptible to the condition.

Growers often suffer the most severe losses from damping-off fungus during the spring months when both the light level and the temperature are low because the seedlings grow slowly in such conditions which make them more vulnerable to fungus infections. However, if the conditions are right, damping-off fungus can occur at any time of year.

Growers can take many steps to prevent their seedlings and cuttings from becoming victim to the fungus such as growing only in soil that is free of fungi. New pots and trays should always be used when sowing fresh seeds. Spread the seeds thinly to prevent overcrowding. Ideally, the greenhouse should be well-ventilated with humidity controls.

Finally, avoiding over-watering seedlings and cuttings also helps prevent damping-off fungus. Old seeds also appear to be more susceptible to the damping-off fungus.

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