What Is Damping Off Its Causes Symptoms and Prevention
Damping off is a disease or condition that occurs in horticultural plants. This condition damages or weakens the seedlings during the process of germination. It is caused by different pathogens and is mostly found in wet and cool conditions. Damping-off is caused by several seed-borne and soil-borne fungi including Rhizoctonia solani and Aphanomyces cochlioides. It is also caused by oomycetes and different fungal species which include Pythium, Fusarium, Phytophthora, Botrytis, Cylindrocladium, Diplodia, Phoma, and Alternaria. Damping off caused by these pathogens has a severe impact on the plant species and can cause great loss to economically important food crops.
Here, we will discuss damping off treatments and causes. One can also refer to this page to know about the common damping off symptoms.
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There are mainly two types of damping off processes, i.e., preemergence damping off and post-emergence damping off. It is caused by the fungus Fusarium equiseti which results in a dry, reddish-brown rot on the hypocotyl. This fungus is the main cause behind both pre-and post-emergence damping-off. Thus, damping off is a serious condition caused to the seeds and must be treated well.
Damping Off Symptoms
Some of the common damping off symptoms that occur in various plant species are given below:
Rotting of seeds before the process of germination causing the seedlings to die before emerging is the first symptom of damping off. This process is also regarded as Pre-emergence damping-off.
Rotting of young seedlings around the crown region, resulting in softening of tissue, wilting, and falling over of plants is another common symptom known as Post-emergence damping-off.
In most cases, the seedlings turn to form a dull green colour along with the drooping of cotyledons. This is mainly caused by Pythium spp. which also causes the development of water-soaked lesions on the hypocotyls at the soil line resulting in seedlings wilt and collapse.
The occurrence of depressed tan to reddish-brown dry on elder seedlings is caused by Rhizoctonia solani, thus infecting seeds and affecting germination. These symptoms are similar to those caused by the Pythium species.
The infection caused by Acremonium spp. tends to develop symptoms usually between 7–10 days after seedling emergence. The infection can be found around the seed coat rand hypocotyl, which turns into a light yellow-brown colour. It develops into a dry red-brown rot within two to three days leading to seedling death.
Development of grey to reddish lesions which later turn coal black in colour. While in wet soil, a frosty coating may cover parts of the black lesion. This symptom is caused by Thielaviopsis basicola.
Damping Off Treatment
Although there is no specific damping off treatment, still use of various precautionary measures can definitely reduce the damping off caused by several pathogens.
We can easily prevent this issue with seedlings by providing good air circulation by use of a small fan. It can also be done by using a cracked lid or germination tray to allow the passing of fresh air. Other steps for preventing damping off include the following:
Use of biological fungicide Mycostop as a seed treatment to prevent seed or soil-borne diseases.
Usage of organic and good quality potting soil
To practise sterilizing your own potting soil in an oven.
To use light and fast-draining seed starter mix.
Planting seedlings in such a manner so that the soil surface is near the top of the container, thus allowing proper air circulation.
Prevent overcrowding of seeds by sowing them in a thin manner. Overcrowding may lead to humid and moist conditions.
Usage of seedling trays that provide water from below. Also, avoid watering the seeds past noon to allow the soil surface and the plants to be dry by evening.
Avoid overwatering of tender seedlings.
FAQs on Damping Off Disease in Plants Explained for Students
1. What is damping off in plants?
Damping off is a fungal disease that causes seeds and young seedlings to rot and collapse, usually at the soil line. It mainly affects plants during early germination and seedling stages.
- Caused by soil-borne pathogens like Pythium, Rhizoctonia, and Fusarium
- Leads to poor seed germination
- Common in nurseries, seed trays, and greenhouse conditions
2. What causes damping off disease?
Damping off is caused by soil-borne fungi and oomycetes that attack seeds and young seedlings under moist conditions. These pathogens thrive in warm, wet, and poorly ventilated environments.
- Overwatering and poor drainage
- High humidity and overcrowding
- Contaminated soil or infected tools
3. What are the symptoms of damping off?
The main symptom of damping off is the sudden collapse of young seedlings due to stem rot at the soil surface. Symptoms vary depending on the stage of infection.
- Pre-emergence damping off: Seeds rot before sprouting
- Post-emergence damping off: Seedlings fall over after emergence
- Water-soaked, thin, or constricted stems near soil line
4. What is the difference between pre-emergence and post-emergence damping off?
Pre-emergence damping off kills seeds before they emerge, while post-emergence damping off destroys seedlings after they sprout. The difference lies in the stage of plant development affected.
- Pre-emergence: Seed decays underground, poor germination observed
- Post-emergence: Visible seedlings collapse at the stem base
5. How does damping off spread?
Damping off spreads through contaminated soil, water, tools, and infected plant debris. The pathogens survive in soil and infect nearby seedlings under favorable conditions.
- Spread by irrigation water splash
- Movement of contaminated soil or trays
- Persistence of fungal spores in soil
6. How can damping off be prevented?
Damping off can be prevented by maintaining clean, well-drained, and properly ventilated growing conditions. Good cultural practices reduce fungal growth.
- Use sterilized or disease-free soil
- Avoid overwatering
- Ensure proper spacing between seedlings
- Disinfect pots and tools before use
7. Which organisms commonly cause damping off?
The most common organisms causing damping off are Pythium spp., Rhizoctonia solani, and Fusarium spp.. These are soil-inhabiting pathogens that infect tender plant tissues.
- Pythium: An oomycete thriving in wet soils
- Rhizoctonia: A true fungus causing stem lesions
- Fusarium: Produces spores that survive long in soil
8. Why are seedlings more vulnerable to damping off?
Seedlings are more vulnerable to damping off because their young tissues are soft, thin, and lack fully developed protective structures. Their immature defense systems make them easy targets for pathogens.
- Thin cuticle and weak stem tissues
- Underdeveloped root system
- High moisture requirement for germination
9. Can damping off affect all types of plants?
Yes, damping off can affect most vegetable, ornamental, and crop plants during their early growth stages. It is especially common in densely planted nursery seedlings.
- Vegetables like tomato, cabbage, and cucumber
- Ornamental flowering plants
- Field crops during early sowing
10. How is damping off controlled in agriculture?
Damping off is controlled through a combination of cultural, biological, and chemical management methods. Integrated disease management reduces pathogen load in soil.
- Soil sterilization or solarization
- Use of biocontrol agents like Trichoderma
- Seed treatment with appropriate fungicides
- Improved drainage and aeration
