What is Root Rot Disease

Root rot is a common disease in plants. Upon infection, the roots of the plant rot and decay. If the infections are severe, the plants may die with no chance of recovery. This disease is usually caused by waterlogging or pathogens in the soil.

This article focuses on Root rot disease, its causes, symptoms and treatment

Root rot disease infects both indoor plants and outdoor plants. However, it is most commonly found infecting the indoor plants. This disease also has a tendency to spread infecting the neighboring plants.

Causes of Root Rot

There are two main causes of Root Rot. They are Water logging and pathogens.

causes of Root Rot

Water Logging

Typically, poor drainage of soils and excess watering leads to water logging. Blocking the aeration of roots, waterlogging causes low oxygenation and decay.

In fact, densely packed garden soils may also block the aeration. This disease also develops due to other factors like poor or excess lighting conditions, improper fertilization, inadequate air flow, water stress and weak root systems.


Pathogens like genus Phytophthora, species P. cinnamomic in particular, causes root rot. In moist conditions, the spores contaminate the plants readily. Usually, the garden soils contain these pathogen spores. So, avoid using it as potting medium for any type of indoor plants.

Common Pathogens


Fusarium fungus is a common soil-borne fungus. This fungus takes over the dying or dead tissues. Hence, it infects the roots readily in moist conditions. It also infects the roots underneath especially at lesions or cuts.


In fact, Pythium is parasitic bacteria. It feeds on decaying plant matter. Under moist conditions, this bacterium feeds on the plant roots casing them to decay. Most commonly, the fungus gnats transport these bacteria across the plants in the garden.


Rhizoctonia solani causes many commercially crucial plant diseases. Typically, these soilborne pathogens produce basidiocarps on plant detritus and dead stems. Having unlimited host range, these pathogens are opportunistic. They also have cosmopolitan (worldwide) distribution.

Other common Pathogens include Armillaria, Rosellinia necatrix, Rhododendron, and Scytinostroma galactinum.

Symptoms of Root Rot

Symptoms of root rot

Photo by Bjornwireen (Wikimedia Commons) (CC BY-SA 3.0)

The roots usually grow underground. Hence, the initial symptoms appearing on roots are not visible. Upon infection, the roots become soft and turn black or dark brown. They lose their strength and become weak. Hence, most infected plants can be pulled out of the earth with less effort than usual.

When the infection enters into advanced stages, the weak roots almost lose their ability to absorb water and essential nutrients from the soil. As the result, the foliage wilts and decolors. The infected plants may also have stunted growth. With time, they may develop cankers or ooze out the sap liquids.

You can cure this lethal disease in the initial stages. But when the disease enters advances stages, the host plants will die with no recovery chances. In some cases, the infected plants die within a short span of 10 days or so.

Dispose of the infected/dead plants immediately. This helps prevent the disease from spreading to other plants.

Treating Root Rot

If the disease is in the initial stages, you can treat the plant. But if the infection is intensive, just remove and dispose of the plant.

1) Uproot the infected plants and wash the root ball thoroughly in running water.

2) Examine the extent of infection. If it is minimal, trim off the infection portion with sterilized garden shears.

3) Prune the foliage in the same ratio as you have trimmed the roots. In fact, this reduces the pressure on trimmed roots to absorb more nutrients and provides time to regrow.

4) Select a disease-free new location that has well-draining soil for transplanting. Amend the soil with organic manure or recommended fertilizer.

5) Dig a hole twice as deep as and as wide as the root ball. Keep the plant in the hole in upright position and backfill the soil.

6) To prevent the progression or recurrence of the disease, reduce the water frequency. Allow the soil to dry in between watering.

For indoor plants, sterilize the used pots with bleach. Use fresh potting soil to regrow the plants.



If the plant is infected mildly, trim the infected portion and transplant the plant to a new location with good drainage. To limit the progression of the disease, you can treat the plants with pathogen specific fungicides. Some best fungicides include chloropicrin, methyl bromide or cinnamon.

However, If the infection is high, destroy the plants immediately and dispose them of. Otherwise, the disease may spread to other healthy plants.

Watering and Aeration

Avoid excessive watering so as to cause water logging. Allow the soil to dry up in between watering. It is also recommended to keep the soil as dry as possible around the plants. For proper aeration, pry back the soil periodically.


At the end of the season, pull out the annuals and prune the perennials. Rake the debris immediately and dispose it off. Otherwise, the soil fungus may feed on the debris and spread through.

Rotation of Crops

Generally, crop rotation prevents or delays the infection to a large extent. Grow crops resistant to specific pathogens in your soil. If your garden is small, you can just leave it without planting for a couple of years. However, you can use containers to grow your veggies in this scenario.


Photo by Makampanda (CC BY-SA 4.0)

Modern commercial growers use Aeroponics to avoid root rot and other diseases. In Aeroponics, the plants are grown in an airy or misty environment without soil. In fact, the plants grow suspended in a semi-closed or closed environment. An automized sprayer sprays nutrient-rich water solution on the lower stems and roots to feed the plant.

Ideally, the plants grow in a pest and disease-free, controlled environment. Hence, the plants tend to grow more quickly and healthily. However, most of the aeroponic environments are not perfectly sealed from the outer atmosphere. Therefore, there is a chance for pest and disease infections. But it is very minimal compared to soil grown plants.

In this program, there is very minimal plant to plant contact. Hence, even if a plant is infected, the chances of disease transmission are very less.

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