Damping off disease is a common and troubling plant condition that causes sections of seedlings’ stock, stem, or trunk to grow thin and weak in the early stages of growth. It also commonly occurs when seeds are planted in cold, wet soils with poor soil drainage.
This fungal disease results in the plant’s inability to stand up or transport sufficient nutrients and water to its leaves and branches.
There is no treatment for the infected plant, which should be removed and destroyed. Therefore, the soil surface must be cleaned or replaced, and growing conditions must be improved.
Damping off disease can be caused by a wide range of pathogens. But it is most often caused by a form of mold or fungi.
The most common cause is either the Pythium or Rhizoctonia fungus species, but there are several other fungi and mold that can cause it.
Spotting Damping Off Disease
The primary symptom is thin, dedicated stem sections. Coloration may or may not become dark, black, brown, or reddish brown.
The thinning of the stem of diseased plants is often abrupt, appearing as if an outside force pinched the stem.
In most cases, the thinning starts at the ground level before the plant emerges from its seed. But the abrupt wasting of the stem can start and stop at any point. The type of damping off disease present is determined by where the “pinching” effect begins.
The thinning of the stem can be so intense that it cuts off the rest of the plant completely, or it can be mild so that the plant is simply weakened.
Either way, the plant is contaminated with one of several known fungi and should be removed and destroyed.
The full list of fungi and mold known to cause the disease is as follows:
- Arthrinium sacchari
- Aphanomyces cochlioides
- Botrytis cinerea
- Fusarium commune
- Macrophomina phaseoli
- Pythium torulosum
- Phytophthora capsica
- Rhizoctonia solani or R. Solani
- Sclerotium rolfsii
Biocontrol agents (Trichoderma viride and Bacillus megaterium) and chemical inducers (salicylic acid [SA] and hydrogen peroxide) individually or in combination were examined for biological control of damping-off and root rot/wilt and growth promoting of faba bean plants in vitro and in vivo.
Although these mold and fungus species are known to cause damping off disease, it is believed that many more pathogens can also cause the condition.
Failure to separate the affected plant from the garden will result in the spread of the disease to other plants.
Types of Damping Off Disease
There are two forms of this disease, and they are defined by the point in the development of the young plant at which symptoms emerge.
The difference is determined by whether active infection begins before or after the seedling emerges from the soil. The two forms of the disease are called Pre-emergence infection and Post-emergence infection.
With Pre-Emergence, the wasting section of the stem will start beneath the surface of the soil and become visible as the plant emerges from the ground.
When a Pre-Emergence infection occurs, the culprit is usually the Pythium or Phytophthora species of fungus.
In Post-Emergence cases, the stem will emerge from the soil’s surface with its full width and strength. Then a section of the thin, wasting stem will suddenly form. This is what causes the pinched appearance so common to this disease.
Post-Emergence infection is usually caused by the Rhizoctonia fungus.
Symptoms Of Damping Off Disease
Here are some noticeable symptoms of damping off disease:
- Thinning or wasting of the stem in sections
- Discoloration of the wasting sections
- Rotting seeds before germination
- Rotting seedlings at the crown
- Softening of stem tissue
- Root rot or crown rot in mature plants
- Infected plants fail to emerge from seeds
- Seedlings typically collapse and die soon after germination.
Visible signs of infection generally appear within 7 to 10 days after the seedling has emerged.
Treating Damping Off Disease
Plants that are affected by these forms of infection cannot be saved. Attempting to fix, heal, or repair an infected plant will spread the pathogen in the soil to other nearby plants.
There is no treatment for the infected plant. The only effective responses will address the presence of pathogens in the soil and are preventative and hygienic in nature.
Any plant found with this or similar infectious diseases should be removed from the soil and burned.
In addition, biocontrol products and chemical inducers like hydrogen peroxide are examples of biological control of damping-off or fungal growth, especially on the seeds of the host plants.
After handling infected plants, you should wash your hands and change your outerwear before tending to other plants.
The soil where infected plants have emerged should be treated with biological fungicide. You may also use chemical fungicides, and several applications may be necessary.
These examples of chemical fungicides should be used:
- One broad spectrum fungicide (captan or ferbam)
- Two specific fungicides (benomyl plus, etridiazole, or metalaxyl)
- A prepared combination of fungicides (etridiazole + thiophanate methyl)
Potting soil can also be sterilized in an oven. Be sure to follow best practices when sterilizing soil in this way. After sterilization, high-quality soil should be installed, preferably from another location.
In addition, you can provide seed treatments to control the pre-emergence form of damping-off. Fungicide-treated seeds will help promote good plant establishment and control this disease.
Proper Growing Conditions
Plants should be grown in favorable conditions and cared for in a way that best suits them. The plant and the soil should be of high quality with adequate drainage. Standing water should be prevented, and an optimal amount of sunlight should be provided.
And since damping off disease is caused by a fungus or mold that thrives in cool, wet conditions, it’s best to have the optimal temperature and environmental conditions for germination before planting outdoors.
Ensure that your soil temperatures do not become low before germination, about 68° degrees Fahrenheit, because this condition greatly favors this disease.
Moreover, you can also easily prevent the problem of damping-off fungi by providing good air circulation.
Optimal Planting Practices
Plants should be spaced out properly, so that root systems do not interfere with each other unduly.
Optimal Plant Care Practices
Every plant you care for should be researched and cared for appropriately to prevent these kinds of plant diseases.
You should know the region of the globe from which the plant originates. You should attempt to emulate the climate and favorable conditions in which the plant species have evolved.
Preventing Damping Off Disease
Any successful response to damping off disease will begin with prevention. Providing optimal growing conditions is key.
Plants under greenhouse conditions should have the ideal amount of water and sunlight. Other helpful options include ensuring the potting soil is healthy, nutrient-dense, and drains well.
Any manifestation of damping off disease indicates the presence of an infectious pathogen on a healthy host plant. Therefore, affected plants should be removed and destroyed. The garden soil where infected plants appear should be sterilized and replaced with quality soil. Doing so will help in the biocontrol of plant pathogens from spreading further.
Seed treatments may also be done to help control the emergence of this fungal disease. Treating seeds with fungicides prevents the disease’s onset beneath the soil surface.
The best fungicide to use in chemical seed treatment is metalaxyl-M, which will help control the damping-off’s pre-emergence form. You may also use foliar spray with captan 31.8% or metalaxyl-M 75%.
Moreover, another technique you can do to prevent this fungal growth from infecting crops is to make your own seed raising mix before sowing seeds.
Conditions should be adversarial to mold and fungus. Standing water should be avoided. Soil should be properly aerated or with good air circulation. Moreover, plants should not be bunched up, and soil should drain effectively.
Growing conditions optimal for the plants in your garden should be provided. Plants should be given the amount of light and water optimal for the species. Healthy seedlings should not be overwatered or watered at the wrong time of day.
Once any infectious disease becomes apparent in your garden, the best response is to remove the plant, followed by the hygienic cleansing of the area. Short of this, damping off disease will spread and persist even on healthy plants.